Text file src/cmd/compile/internal/ssa/_gen/generic.rules

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Simplifications that apply to all backend architectures. As an example, this
     6  // Go source code
     7  //
     8  // y := 0 * x
     9  //
    10  // can be translated into y := 0 without losing any information, which saves a
    11  // pointless multiplication instruction. Other .rules files in this directory
    12  // (for example AMD64.rules) contain rules specific to the architecture in the
    13  // filename. The rules here apply to every architecture.
    14  //
    15  // The code for parsing this file lives in rulegen.go; this file generates
    16  // ssa/rewritegeneric.go.
    17  
    18  // values are specified using the following format:
    19  // (op <type> [auxint] {aux} arg0 arg1 ...)
    20  // the type, aux, and auxint fields are optional
    21  // on the matching side
    22  //  - the type, aux, and auxint fields must match if they are specified.
    23  //  - the first occurrence of a variable defines that variable.  Subsequent
    24  //    uses must match (be == to) the first use.
    25  //  - v is defined to be the value matched.
    26  //  - an additional conditional can be provided after the match pattern with "&&".
    27  // on the generated side
    28  //  - the type of the top-level expression is the same as the one on the left-hand side.
    29  //  - the type of any subexpressions must be specified explicitly (or
    30  //    be specified in the op's type field).
    31  //  - auxint will be 0 if not specified.
    32  //  - aux will be nil if not specified.
    33  
    34  // blocks are specified using the following format:
    35  // (kind controlvalue succ0 succ1 ...)
    36  // controlvalue must be "nil" or a value expression
    37  // succ* fields must be variables
    38  // For now, the generated successors must be a permutation of the matched successors.
    39  
    40  // constant folding
    41  (Trunc16to8  (Const16  [c])) => (Const8   [int8(c)])
    42  (Trunc32to8  (Const32  [c])) => (Const8   [int8(c)])
    43  (Trunc32to16 (Const32  [c])) => (Const16  [int16(c)])
    44  (Trunc64to8  (Const64  [c])) => (Const8   [int8(c)])
    45  (Trunc64to16 (Const64  [c])) => (Const16  [int16(c)])
    46  (Trunc64to32 (Const64  [c])) => (Const32  [int32(c)])
    47  (Cvt64Fto32F (Const64F [c])) => (Const32F [float32(c)])
    48  (Cvt32Fto64F (Const32F [c])) => (Const64F [float64(c)])
    49  (Cvt32to32F  (Const32  [c])) => (Const32F [float32(c)])
    50  (Cvt32to64F  (Const32  [c])) => (Const64F [float64(c)])
    51  (Cvt64to32F  (Const64  [c])) => (Const32F [float32(c)])
    52  (Cvt64to64F  (Const64  [c])) => (Const64F [float64(c)])
    53  (Cvt32Fto32  (Const32F [c])) => (Const32  [int32(c)])
    54  (Cvt32Fto64  (Const32F [c])) => (Const64  [int64(c)])
    55  (Cvt64Fto32  (Const64F [c])) => (Const32  [int32(c)])
    56  (Cvt64Fto64  (Const64F [c])) => (Const64  [int64(c)])
    57  (Round32F x:(Const32F)) => x
    58  (Round64F x:(Const64F)) => x
    59  (CvtBoolToUint8 (ConstBool [false])) => (Const8 [0])
    60  (CvtBoolToUint8 (ConstBool [true])) => (Const8 [1])
    61  
    62  (Trunc16to8  (ZeroExt8to16  x)) => x
    63  (Trunc32to8  (ZeroExt8to32  x)) => x
    64  (Trunc32to16 (ZeroExt8to32  x)) => (ZeroExt8to16  x)
    65  (Trunc32to16 (ZeroExt16to32 x)) => x
    66  (Trunc64to8  (ZeroExt8to64  x)) => x
    67  (Trunc64to16 (ZeroExt8to64  x)) => (ZeroExt8to16  x)
    68  (Trunc64to16 (ZeroExt16to64 x)) => x
    69  (Trunc64to32 (ZeroExt8to64  x)) => (ZeroExt8to32  x)
    70  (Trunc64to32 (ZeroExt16to64 x)) => (ZeroExt16to32 x)
    71  (Trunc64to32 (ZeroExt32to64 x)) => x
    72  (Trunc16to8  (SignExt8to16  x)) => x
    73  (Trunc32to8  (SignExt8to32  x)) => x
    74  (Trunc32to16 (SignExt8to32  x)) => (SignExt8to16  x)
    75  (Trunc32to16 (SignExt16to32 x)) => x
    76  (Trunc64to8  (SignExt8to64  x)) => x
    77  (Trunc64to16 (SignExt8to64  x)) => (SignExt8to16  x)
    78  (Trunc64to16 (SignExt16to64 x)) => x
    79  (Trunc64to32 (SignExt8to64  x)) => (SignExt8to32  x)
    80  (Trunc64to32 (SignExt16to64 x)) => (SignExt16to32 x)
    81  (Trunc64to32 (SignExt32to64 x)) => x
    82  
    83  (ZeroExt8to16  (Const8  [c])) => (Const16 [int16( uint8(c))])
    84  (ZeroExt8to32  (Const8  [c])) => (Const32 [int32( uint8(c))])
    85  (ZeroExt8to64  (Const8  [c])) => (Const64 [int64( uint8(c))])
    86  (ZeroExt16to32 (Const16 [c])) => (Const32 [int32(uint16(c))])
    87  (ZeroExt16to64 (Const16 [c])) => (Const64 [int64(uint16(c))])
    88  (ZeroExt32to64 (Const32 [c])) => (Const64 [int64(uint32(c))])
    89  (SignExt8to16  (Const8  [c])) => (Const16 [int16(c)])
    90  (SignExt8to32  (Const8  [c])) => (Const32 [int32(c)])
    91  (SignExt8to64  (Const8  [c])) => (Const64 [int64(c)])
    92  (SignExt16to32 (Const16 [c])) => (Const32 [int32(c)])
    93  (SignExt16to64 (Const16 [c])) => (Const64 [int64(c)])
    94  (SignExt32to64 (Const32 [c])) => (Const64 [int64(c)])
    95  
    96  (Neg8   (Const8   [c])) => (Const8   [-c])
    97  (Neg16  (Const16  [c])) => (Const16  [-c])
    98  (Neg32  (Const32  [c])) => (Const32  [-c])
    99  (Neg64  (Const64  [c])) => (Const64  [-c])
   100  (Neg32F (Const32F [c])) && c != 0 => (Const32F [-c])
   101  (Neg64F (Const64F [c])) && c != 0 => (Const64F [-c])
   102  
   103  (Add8   (Const8 [c])   (Const8 [d]))   => (Const8  [c+d])
   104  (Add16  (Const16 [c])  (Const16 [d]))  => (Const16 [c+d])
   105  (Add32  (Const32 [c])  (Const32 [d]))  => (Const32 [c+d])
   106  (Add64  (Const64 [c])  (Const64 [d]))  => (Const64 [c+d])
   107  (Add32F (Const32F [c]) (Const32F [d])) && c+d == c+d => (Const32F [c+d])
   108  (Add64F (Const64F [c]) (Const64F [d])) && c+d == c+d => (Const64F [c+d])
   109  (AddPtr <t> x (Const64 [c])) => (OffPtr <t> x [c])
   110  (AddPtr <t> x (Const32 [c])) => (OffPtr <t> x [int64(c)])
   111  
   112  (Sub8   (Const8 [c]) (Const8 [d]))     => (Const8 [c-d])
   113  (Sub16  (Const16 [c]) (Const16 [d]))   => (Const16 [c-d])
   114  (Sub32  (Const32 [c]) (Const32 [d]))   => (Const32 [c-d])
   115  (Sub64  (Const64 [c]) (Const64 [d]))   => (Const64 [c-d])
   116  (Sub32F (Const32F [c]) (Const32F [d])) && c-d == c-d => (Const32F [c-d])
   117  (Sub64F (Const64F [c]) (Const64F [d])) && c-d == c-d => (Const64F [c-d])
   118  
   119  (Mul8   (Const8 [c])   (Const8 [d]))   => (Const8  [c*d])
   120  (Mul16  (Const16 [c])  (Const16 [d]))  => (Const16 [c*d])
   121  (Mul32  (Const32 [c])  (Const32 [d]))  => (Const32 [c*d])
   122  (Mul64  (Const64 [c])  (Const64 [d]))  => (Const64 [c*d])
   123  (Mul32F (Const32F [c]) (Const32F [d])) && c*d == c*d => (Const32F [c*d])
   124  (Mul64F (Const64F [c]) (Const64F [d])) && c*d == c*d => (Const64F [c*d])
   125  
   126  (And8   (Const8 [c])   (Const8 [d]))   => (Const8  [c&d])
   127  (And16  (Const16 [c])  (Const16 [d]))  => (Const16 [c&d])
   128  (And32  (Const32 [c])  (Const32 [d]))  => (Const32 [c&d])
   129  (And64  (Const64 [c])  (Const64 [d]))  => (Const64 [c&d])
   130  
   131  (Or8   (Const8 [c])   (Const8 [d]))   => (Const8  [c|d])
   132  (Or16  (Const16 [c])  (Const16 [d]))  => (Const16 [c|d])
   133  (Or32  (Const32 [c])  (Const32 [d]))  => (Const32 [c|d])
   134  (Or64  (Const64 [c])  (Const64 [d]))  => (Const64 [c|d])
   135  
   136  (Xor8   (Const8 [c])   (Const8 [d]))   => (Const8  [c^d])
   137  (Xor16  (Const16 [c])  (Const16 [d]))  => (Const16 [c^d])
   138  (Xor32  (Const32 [c])  (Const32 [d]))  => (Const32 [c^d])
   139  (Xor64  (Const64 [c])  (Const64 [d]))  => (Const64 [c^d])
   140  
   141  (Ctz64 (Const64 [c])) && config.PtrSize == 4 => (Const32 [int32(ntz64(c))])
   142  (Ctz32 (Const32 [c])) && config.PtrSize == 4 => (Const32 [int32(ntz32(c))])
   143  (Ctz16 (Const16 [c])) && config.PtrSize == 4 => (Const32 [int32(ntz16(c))])
   144  (Ctz8  (Const8  [c])) && config.PtrSize == 4 => (Const32 [int32(ntz8(c))])
   145  
   146  (Ctz64 (Const64 [c])) && config.PtrSize == 8 => (Const64 [int64(ntz64(c))])
   147  (Ctz32 (Const32 [c])) && config.PtrSize == 8 => (Const64 [int64(ntz32(c))])
   148  (Ctz16 (Const16 [c])) && config.PtrSize == 8 => (Const64 [int64(ntz16(c))])
   149  (Ctz8  (Const8  [c])) && config.PtrSize == 8 => (Const64 [int64(ntz8(c))])
   150  
   151  (Div8   (Const8  [c])  (Const8  [d])) && d != 0 => (Const8  [c/d])
   152  (Div16  (Const16 [c])  (Const16 [d])) && d != 0 => (Const16 [c/d])
   153  (Div32  (Const32 [c])  (Const32 [d])) && d != 0 => (Const32 [c/d])
   154  (Div64  (Const64 [c])  (Const64 [d])) && d != 0 => (Const64 [c/d])
   155  (Div8u  (Const8  [c])  (Const8  [d])) && d != 0 => (Const8  [int8(uint8(c)/uint8(d))])
   156  (Div16u (Const16 [c])  (Const16 [d])) && d != 0 => (Const16 [int16(uint16(c)/uint16(d))])
   157  (Div32u (Const32 [c])  (Const32 [d])) && d != 0 => (Const32 [int32(uint32(c)/uint32(d))])
   158  (Div64u (Const64 [c])  (Const64 [d])) && d != 0 => (Const64 [int64(uint64(c)/uint64(d))])
   159  (Div32F (Const32F [c]) (Const32F [d])) && c/d == c/d => (Const32F [c/d])
   160  (Div64F (Const64F [c]) (Const64F [d])) && c/d == c/d => (Const64F [c/d])
   161  (Select0 (Div128u (Const64 [0]) lo y)) => (Div64u lo y)
   162  (Select1 (Div128u (Const64 [0]) lo y)) => (Mod64u lo y)
   163  
   164  (Not (ConstBool [c])) => (ConstBool [!c])
   165  
   166  (Floor       (Const64F [c])) => (Const64F [math.Floor(c)])
   167  (Ceil        (Const64F [c])) => (Const64F [math.Ceil(c)])
   168  (Trunc       (Const64F [c])) => (Const64F [math.Trunc(c)])
   169  (RoundToEven (Const64F [c])) => (Const64F [math.RoundToEven(c)])
   170  
   171  // Convert x * 1 to x.
   172  (Mul(8|16|32|64)  (Const(8|16|32|64)  [1]) x) => x
   173  (Select0 (Mul(32|64)uover (Const(32|64) [1]) x)) => x
   174  (Select1 (Mul(32|64)uover (Const(32|64) [1]) x)) => (ConstBool [false])
   175  
   176  // Convert x * -1 to -x.
   177  (Mul(8|16|32|64)  (Const(8|16|32|64)  [-1]) x) => (Neg(8|16|32|64)  x)
   178  
   179  // DeMorgan's Laws
   180  (And(8|16|32|64) <t> (Com(8|16|32|64) x) (Com(8|16|32|64) y)) => (Com(8|16|32|64) (Or(8|16|32|64) <t> x y))
   181  (Or(8|16|32|64) <t> (Com(8|16|32|64) x) (Com(8|16|32|64) y)) => (Com(8|16|32|64) (And(8|16|32|64) <t> x y))
   182  
   183  // Convert multiplication by a power of two to a shift.
   184  (Mul8  <t> n (Const8  [c])) && isPowerOfTwo8(c) => (Lsh8x64  <t> n (Const64 <typ.UInt64> [log8(c)]))
   185  (Mul16 <t> n (Const16 [c])) && isPowerOfTwo16(c) => (Lsh16x64 <t> n (Const64 <typ.UInt64> [log16(c)]))
   186  (Mul32 <t> n (Const32 [c])) && isPowerOfTwo32(c) => (Lsh32x64 <t> n (Const64 <typ.UInt64> [log32(c)]))
   187  (Mul64 <t> n (Const64 [c])) && isPowerOfTwo64(c) => (Lsh64x64 <t> n (Const64 <typ.UInt64> [log64(c)]))
   188  (Mul8  <t> n (Const8  [c])) && t.IsSigned() && isPowerOfTwo8(-c)  => (Neg8  (Lsh8x64  <t> n (Const64 <typ.UInt64> [log8(-c)])))
   189  (Mul16 <t> n (Const16 [c])) && t.IsSigned() && isPowerOfTwo16(-c) => (Neg16 (Lsh16x64 <t> n (Const64 <typ.UInt64> [log16(-c)])))
   190  (Mul32 <t> n (Const32 [c])) && t.IsSigned() && isPowerOfTwo32(-c) => (Neg32 (Lsh32x64 <t> n (Const64 <typ.UInt64> [log32(-c)])))
   191  (Mul64 <t> n (Const64 [c])) && t.IsSigned() && isPowerOfTwo64(-c) => (Neg64 (Lsh64x64 <t> n (Const64 <typ.UInt64> [log64(-c)])))
   192  
   193  (Mod8  (Const8  [c]) (Const8  [d])) && d != 0 => (Const8  [c % d])
   194  (Mod16 (Const16 [c]) (Const16 [d])) && d != 0 => (Const16 [c % d])
   195  (Mod32 (Const32 [c]) (Const32 [d])) && d != 0 => (Const32 [c % d])
   196  (Mod64 (Const64 [c]) (Const64 [d])) && d != 0 => (Const64 [c % d])
   197  
   198  (Mod8u  (Const8 [c])  (Const8  [d])) && d != 0 => (Const8  [int8(uint8(c) % uint8(d))])
   199  (Mod16u (Const16 [c]) (Const16 [d])) && d != 0 => (Const16 [int16(uint16(c) % uint16(d))])
   200  (Mod32u (Const32 [c]) (Const32 [d])) && d != 0 => (Const32 [int32(uint32(c) % uint32(d))])
   201  (Mod64u (Const64 [c]) (Const64 [d])) && d != 0 => (Const64 [int64(uint64(c) % uint64(d))])
   202  
   203  (Lsh64x64  (Const64 [c]) (Const64 [d])) => (Const64 [c << uint64(d)])
   204  (Rsh64x64  (Const64 [c]) (Const64 [d])) => (Const64 [c >> uint64(d)])
   205  (Rsh64Ux64 (Const64 [c]) (Const64 [d])) => (Const64 [int64(uint64(c) >> uint64(d))])
   206  (Lsh32x64  (Const32 [c]) (Const64 [d])) => (Const32 [c << uint64(d)])
   207  (Rsh32x64  (Const32 [c]) (Const64 [d])) => (Const32 [c >> uint64(d)])
   208  (Rsh32Ux64 (Const32 [c]) (Const64 [d])) => (Const32 [int32(uint32(c) >> uint64(d))])
   209  (Lsh16x64  (Const16 [c]) (Const64 [d])) => (Const16 [c << uint64(d)])
   210  (Rsh16x64  (Const16 [c]) (Const64 [d])) => (Const16 [c >> uint64(d)])
   211  (Rsh16Ux64 (Const16 [c]) (Const64 [d])) => (Const16 [int16(uint16(c) >> uint64(d))])
   212  (Lsh8x64   (Const8  [c]) (Const64 [d])) => (Const8  [c << uint64(d)])
   213  (Rsh8x64   (Const8  [c]) (Const64 [d])) => (Const8  [c >> uint64(d)])
   214  (Rsh8Ux64  (Const8  [c]) (Const64 [d])) => (Const8  [int8(uint8(c) >> uint64(d))])
   215  
   216  // Fold IsInBounds when the range of the index cannot exceed the limit.
   217  (IsInBounds (ZeroExt8to32  _) (Const32 [c])) && (1 << 8)  <= c => (ConstBool [true])
   218  (IsInBounds (ZeroExt8to64  _) (Const64 [c])) && (1 << 8)  <= c => (ConstBool [true])
   219  (IsInBounds (ZeroExt16to32 _) (Const32 [c])) && (1 << 16) <= c => (ConstBool [true])
   220  (IsInBounds (ZeroExt16to64 _) (Const64 [c])) && (1 << 16) <= c => (ConstBool [true])
   221  (IsInBounds x x) => (ConstBool [false])
   222  (IsInBounds                (And8  (Const8  [c]) _)  (Const8  [d])) && 0 <= c && c < d => (ConstBool [true])
   223  (IsInBounds (ZeroExt8to16  (And8  (Const8  [c]) _)) (Const16 [d])) && 0 <= c && int16(c) < d => (ConstBool [true])
   224  (IsInBounds (ZeroExt8to32  (And8  (Const8  [c]) _)) (Const32 [d])) && 0 <= c && int32(c) < d => (ConstBool [true])
   225  (IsInBounds (ZeroExt8to64  (And8  (Const8  [c]) _)) (Const64 [d])) && 0 <= c && int64(c) < d => (ConstBool [true])
   226  (IsInBounds                (And16 (Const16 [c]) _)  (Const16 [d])) && 0 <= c && c < d => (ConstBool [true])
   227  (IsInBounds (ZeroExt16to32 (And16 (Const16 [c]) _)) (Const32 [d])) && 0 <= c && int32(c) < d => (ConstBool [true])
   228  (IsInBounds (ZeroExt16to64 (And16 (Const16 [c]) _)) (Const64 [d])) && 0 <= c && int64(c) < d => (ConstBool [true])
   229  (IsInBounds                (And32 (Const32 [c]) _)  (Const32 [d])) && 0 <= c && c < d => (ConstBool [true])
   230  (IsInBounds (ZeroExt32to64 (And32 (Const32 [c]) _)) (Const64 [d])) && 0 <= c && int64(c) < d => (ConstBool [true])
   231  (IsInBounds                (And64 (Const64 [c]) _)  (Const64 [d])) && 0 <= c && c < d => (ConstBool [true])
   232  (IsInBounds (Const32 [c]) (Const32 [d])) => (ConstBool [0 <= c && c < d])
   233  (IsInBounds (Const64 [c]) (Const64 [d])) => (ConstBool [0 <= c && c < d])
   234  // (Mod64u x y) is always between 0 (inclusive) and y (exclusive).
   235  (IsInBounds (Mod32u _ y) y) => (ConstBool [true])
   236  (IsInBounds (Mod64u _ y) y) => (ConstBool [true])
   237  // Right shifting an unsigned number limits its value.
   238  (IsInBounds (ZeroExt8to64  (Rsh8Ux64  _ (Const64 [c]))) (Const64 [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   239  (IsInBounds (ZeroExt8to32  (Rsh8Ux64  _ (Const64 [c]))) (Const32 [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   240  (IsInBounds (ZeroExt8to16  (Rsh8Ux64  _ (Const64 [c]))) (Const16 [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   241  (IsInBounds                (Rsh8Ux64  _ (Const64 [c]))  (Const64 [d])) && 0 < c && c <  8 && 1<<uint( 8-c)-1 < d => (ConstBool [true])
   242  (IsInBounds (ZeroExt16to64 (Rsh16Ux64 _ (Const64 [c]))) (Const64 [d])) && 0 < c && c < 16 && 1<<uint(16-c)-1 < d => (ConstBool [true])
   243  (IsInBounds (ZeroExt16to32 (Rsh16Ux64 _ (Const64 [c]))) (Const64 [d])) && 0 < c && c < 16 && 1<<uint(16-c)-1 < d => (ConstBool [true])
   244  (IsInBounds                (Rsh16Ux64 _ (Const64 [c]))  (Const64 [d])) && 0 < c && c < 16 && 1<<uint(16-c)-1 < d => (ConstBool [true])
   245  (IsInBounds (ZeroExt32to64 (Rsh32Ux64 _ (Const64 [c]))) (Const64 [d])) && 0 < c && c < 32 && 1<<uint(32-c)-1 < d => (ConstBool [true])
   246  (IsInBounds                (Rsh32Ux64 _ (Const64 [c]))  (Const64 [d])) && 0 < c && c < 32 && 1<<uint(32-c)-1 < d => (ConstBool [true])
   247  (IsInBounds                (Rsh64Ux64 _ (Const64 [c]))  (Const64 [d])) && 0 < c && c < 64 && 1<<uint(64-c)-1 < d => (ConstBool [true])
   248  
   249  (IsSliceInBounds x x) => (ConstBool [true])
   250  (IsSliceInBounds (And32 (Const32 [c]) _) (Const32 [d])) && 0 <= c && c <= d => (ConstBool [true])
   251  (IsSliceInBounds (And64 (Const64 [c]) _) (Const64 [d])) && 0 <= c && c <= d => (ConstBool [true])
   252  (IsSliceInBounds (Const32 [0]) _) => (ConstBool [true])
   253  (IsSliceInBounds (Const64 [0]) _) => (ConstBool [true])
   254  (IsSliceInBounds (Const32 [c]) (Const32 [d])) => (ConstBool [0 <= c && c <= d])
   255  (IsSliceInBounds (Const64 [c]) (Const64 [d])) => (ConstBool [0 <= c && c <= d])
   256  (IsSliceInBounds (SliceLen x) (SliceCap x)) => (ConstBool [true])
   257  
   258  (Eq(64|32|16|8) x x) => (ConstBool [true])
   259  (EqB (ConstBool [c]) (ConstBool [d])) => (ConstBool [c == d])
   260  (EqB (ConstBool [false]) x) => (Not x)
   261  (EqB (ConstBool [true]) x) => x
   262  
   263  (Neq(64|32|16|8) x x) => (ConstBool [false])
   264  (NeqB (ConstBool [c]) (ConstBool [d])) => (ConstBool [c != d])
   265  (NeqB (ConstBool [false]) x) => x
   266  (NeqB (ConstBool [true]) x) => (Not x)
   267  (NeqB (Not x) (Not y)) => (NeqB x y)
   268  
   269  (Eq64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Eq64 (Const64 <t> [c-d]) x)
   270  (Eq32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Eq32 (Const32 <t> [c-d]) x)
   271  (Eq16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) => (Eq16 (Const16 <t> [c-d]) x)
   272  (Eq8  (Const8  <t> [c]) (Add8  (Const8  <t> [d]) x)) => (Eq8  (Const8  <t> [c-d]) x)
   273  
   274  (Neq64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Neq64 (Const64 <t> [c-d]) x)
   275  (Neq32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Neq32 (Const32 <t> [c-d]) x)
   276  (Neq16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) => (Neq16 (Const16 <t> [c-d]) x)
   277  (Neq8  (Const8  <t> [c]) (Add8  (Const8  <t> [d]) x)) => (Neq8  (Const8  <t> [c-d]) x)
   278  
   279  // signed integer range: ( c <= x && x (<|<=) d ) -> ( unsigned(x-c) (<|<=) unsigned(d-c) )
   280  (AndB (Leq64 (Const64 [c]) x) ((Less|Leq)64 x (Const64 [d]))) && d >= c => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c])) (Const64 <x.Type> [d-c]))
   281  (AndB (Leq32 (Const32 [c]) x) ((Less|Leq)32 x (Const32 [d]))) && d >= c => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c])) (Const32 <x.Type> [d-c]))
   282  (AndB (Leq16 (Const16 [c]) x) ((Less|Leq)16 x (Const16 [d]))) && d >= c => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c])) (Const16 <x.Type> [d-c]))
   283  (AndB (Leq8  (Const8  [c]) x) ((Less|Leq)8  x (Const8  [d]))) && d >= c => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c])) (Const8  <x.Type> [d-c]))
   284  
   285  // signed integer range: ( c < x && x (<|<=) d ) -> ( unsigned(x-(c+1)) (<|<=) unsigned(d-(c+1)) )
   286  (AndB (Less64 (Const64 [c]) x) ((Less|Leq)64 x (Const64 [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c+1])) (Const64 <x.Type> [d-c-1]))
   287  (AndB (Less32 (Const32 [c]) x) ((Less|Leq)32 x (Const32 [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c+1])) (Const32 <x.Type> [d-c-1]))
   288  (AndB (Less16 (Const16 [c]) x) ((Less|Leq)16 x (Const16 [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c+1])) (Const16 <x.Type> [d-c-1]))
   289  (AndB (Less8  (Const8  [c]) x) ((Less|Leq)8  x (Const8  [d]))) && d >= c+1 && c+1 > c => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c+1])) (Const8  <x.Type> [d-c-1]))
   290  
   291  // unsigned integer range: ( c <= x && x (<|<=) d ) -> ( x-c (<|<=) d-c )
   292  (AndB (Leq64U (Const64 [c]) x) ((Less|Leq)64U x (Const64 [d]))) && uint64(d) >= uint64(c) => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c])) (Const64 <x.Type> [d-c]))
   293  (AndB (Leq32U (Const32 [c]) x) ((Less|Leq)32U x (Const32 [d]))) && uint32(d) >= uint32(c) => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c])) (Const32 <x.Type> [d-c]))
   294  (AndB (Leq16U (Const16 [c]) x) ((Less|Leq)16U x (Const16 [d]))) && uint16(d) >= uint16(c) => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c])) (Const16 <x.Type> [d-c]))
   295  (AndB (Leq8U  (Const8  [c]) x) ((Less|Leq)8U  x (Const8  [d]))) && uint8(d)  >= uint8(c)  => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c])) (Const8  <x.Type> [d-c]))
   296  
   297  // unsigned integer range: ( c < x && x (<|<=) d ) -> ( x-(c+1) (<|<=) d-(c+1) )
   298  (AndB (Less64U (Const64 [c]) x) ((Less|Leq)64U x (Const64 [d]))) && uint64(d) >= uint64(c+1) && uint64(c+1) > uint64(c) => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c+1])) (Const64 <x.Type> [d-c-1]))
   299  (AndB (Less32U (Const32 [c]) x) ((Less|Leq)32U x (Const32 [d]))) && uint32(d) >= uint32(c+1) && uint32(c+1) > uint32(c) => ((Less|Leq)32U (Sub32 <x.Type> x (Const32 <x.Type> [c+1])) (Const32 <x.Type> [d-c-1]))
   300  (AndB (Less16U (Const16 [c]) x) ((Less|Leq)16U x (Const16 [d]))) && uint16(d) >= uint16(c+1) && uint16(c+1) > uint16(c) => ((Less|Leq)16U (Sub16 <x.Type> x (Const16 <x.Type> [c+1])) (Const16 <x.Type> [d-c-1]))
   301  (AndB (Less8U  (Const8  [c]) x) ((Less|Leq)8U  x (Const8  [d]))) && uint8(d)  >= uint8(c+1)  && uint8(c+1)  > uint8(c)  => ((Less|Leq)8U  (Sub8  <x.Type> x (Const8  <x.Type> [c+1]))  (Const8  <x.Type> [d-c-1]))
   302  
   303  // signed integer range: ( c (<|<=) x || x < d ) -> ( unsigned(c-d) (<|<=) unsigned(x-d) )
   304  (OrB ((Less|Leq)64 (Const64 [c]) x) (Less64 x (Const64 [d]))) && c >= d => ((Less|Leq)64U (Const64 <x.Type> [c-d]) (Sub64 <x.Type> x (Const64 <x.Type> [d])))
   305  (OrB ((Less|Leq)32 (Const32 [c]) x) (Less32 x (Const32 [d]))) && c >= d => ((Less|Leq)32U (Const32 <x.Type> [c-d]) (Sub32 <x.Type> x (Const32 <x.Type> [d])))
   306  (OrB ((Less|Leq)16 (Const16 [c]) x) (Less16 x (Const16 [d]))) && c >= d => ((Less|Leq)16U (Const16 <x.Type> [c-d]) (Sub16 <x.Type> x (Const16 <x.Type> [d])))
   307  (OrB ((Less|Leq)8  (Const8  [c]) x) (Less8  x (Const8  [d]))) && c >= d => ((Less|Leq)8U  (Const8  <x.Type> [c-d]) (Sub8  <x.Type> x (Const8  <x.Type> [d])))
   308  
   309  // signed integer range: ( c (<|<=) x || x <= d ) -> ( unsigned(c-(d+1)) (<|<=) unsigned(x-(d+1)) )
   310  (OrB ((Less|Leq)64 (Const64 [c]) x) (Leq64 x (Const64 [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)64U (Const64 <x.Type> [c-d-1]) (Sub64 <x.Type> x (Const64 <x.Type> [d+1])))
   311  (OrB ((Less|Leq)32 (Const32 [c]) x) (Leq32 x (Const32 [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)32U (Const32 <x.Type> [c-d-1]) (Sub32 <x.Type> x (Const32 <x.Type> [d+1])))
   312  (OrB ((Less|Leq)16 (Const16 [c]) x) (Leq16 x (Const16 [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)16U (Const16 <x.Type> [c-d-1]) (Sub16 <x.Type> x (Const16 <x.Type> [d+1])))
   313  (OrB ((Less|Leq)8  (Const8  [c]) x) (Leq8  x (Const8  [d]))) && c >= d+1 && d+1 > d => ((Less|Leq)8U  (Const8  <x.Type> [c-d-1]) (Sub8  <x.Type> x (Const8  <x.Type> [d+1])))
   314  
   315  // unsigned integer range: ( c (<|<=) x || x < d ) -> ( c-d (<|<=) x-d )
   316  (OrB ((Less|Leq)64U (Const64 [c]) x) (Less64U x (Const64 [d]))) && uint64(c) >= uint64(d) => ((Less|Leq)64U (Const64 <x.Type> [c-d]) (Sub64 <x.Type> x (Const64 <x.Type> [d])))
   317  (OrB ((Less|Leq)32U (Const32 [c]) x) (Less32U x (Const32 [d]))) && uint32(c) >= uint32(d) => ((Less|Leq)32U (Const32 <x.Type> [c-d]) (Sub32 <x.Type> x (Const32 <x.Type> [d])))
   318  (OrB ((Less|Leq)16U (Const16 [c]) x) (Less16U x (Const16 [d]))) && uint16(c) >= uint16(d) => ((Less|Leq)16U (Const16 <x.Type> [c-d]) (Sub16 <x.Type> x (Const16 <x.Type> [d])))
   319  (OrB ((Less|Leq)8U  (Const8  [c]) x) (Less8U  x (Const8  [d]))) && uint8(c)  >= uint8(d)  => ((Less|Leq)8U  (Const8  <x.Type> [c-d]) (Sub8  <x.Type> x (Const8  <x.Type> [d])))
   320  
   321  // unsigned integer range: ( c (<|<=) x || x <= d ) -> ( c-(d+1) (<|<=) x-(d+1) )
   322  (OrB ((Less|Leq)64U (Const64 [c]) x) (Leq64U x (Const64 [d]))) && uint64(c) >= uint64(d+1) && uint64(d+1) > uint64(d) => ((Less|Leq)64U (Const64 <x.Type> [c-d-1]) (Sub64 <x.Type> x (Const64 <x.Type> [d+1])))
   323  (OrB ((Less|Leq)32U (Const32 [c]) x) (Leq32U x (Const32 [d]))) && uint32(c) >= uint32(d+1) && uint32(d+1) > uint32(d) => ((Less|Leq)32U (Const32 <x.Type> [c-d-1]) (Sub32 <x.Type> x (Const32 <x.Type> [d+1])))
   324  (OrB ((Less|Leq)16U (Const16 [c]) x) (Leq16U x (Const16 [d]))) && uint16(c) >= uint16(d+1) && uint16(d+1) > uint16(d) => ((Less|Leq)16U (Const16 <x.Type> [c-d-1]) (Sub16 <x.Type> x (Const16 <x.Type> [d+1])))
   325  (OrB ((Less|Leq)8U  (Const8  [c]) x) (Leq8U  x (Const8  [d]))) && uint8(c)  >= uint8(d+1)  && uint8(d+1)  > uint8(d)  => ((Less|Leq)8U  (Const8  <x.Type> [c-d-1]) (Sub8  <x.Type> x (Const8  <x.Type> [d+1])))
   326  
   327  // Canonicalize x-const to x+(-const)
   328  (Sub64 x (Const64 <t> [c])) && x.Op != OpConst64 => (Add64 (Const64 <t> [-c]) x)
   329  (Sub32 x (Const32 <t> [c])) && x.Op != OpConst32 => (Add32 (Const32 <t> [-c]) x)
   330  (Sub16 x (Const16 <t> [c])) && x.Op != OpConst16 => (Add16 (Const16 <t> [-c]) x)
   331  (Sub8  x (Const8  <t> [c])) && x.Op != OpConst8  => (Add8  (Const8  <t> [-c]) x)
   332  
   333  // fold negation into comparison operators
   334  (Not (Eq(64|32|16|8|B|Ptr|64F|32F) x y)) => (Neq(64|32|16|8|B|Ptr|64F|32F) x y)
   335  (Not (Neq(64|32|16|8|B|Ptr|64F|32F) x y)) => (Eq(64|32|16|8|B|Ptr|64F|32F) x y)
   336  
   337  (Not (Less(64|32|16|8) x y)) => (Leq(64|32|16|8) y x)
   338  (Not (Less(64|32|16|8)U x y)) => (Leq(64|32|16|8)U y x)
   339  (Not (Leq(64|32|16|8) x y)) => (Less(64|32|16|8) y x)
   340  (Not (Leq(64|32|16|8)U x y)) => (Less(64|32|16|8)U y x)
   341  
   342  // Distribute multiplication c * (d+x) -> c*d + c*x. Useful for:
   343  // a[i].b = ...; a[i+1].b = ...
   344  (Mul64 (Const64 <t> [c]) (Add64 <t> (Const64 <t> [d]) x)) =>
   345    (Add64 (Const64 <t> [c*d]) (Mul64 <t> (Const64 <t> [c]) x))
   346  (Mul32 (Const32 <t> [c]) (Add32 <t> (Const32 <t> [d]) x)) =>
   347    (Add32 (Const32 <t> [c*d]) (Mul32 <t> (Const32 <t> [c]) x))
   348  
   349  // Rewrite x*y ± x*z  to  x*(y±z)
   350  (Add(64|32|16|8) <t> (Mul(64|32|16|8) x y) (Mul(64|32|16|8) x z))
   351  	=> (Mul(64|32|16|8) x (Add(64|32|16|8) <t> y z))
   352  (Sub(64|32|16|8) <t> (Mul(64|32|16|8) x y) (Mul(64|32|16|8) x z))
   353  	=> (Mul(64|32|16|8) x (Sub(64|32|16|8) <t> y z))
   354  
   355  // rewrite shifts of 8/16/32 bit consts into 64 bit consts to reduce
   356  // the number of the other rewrite rules for const shifts
   357  (Lsh64x32  <t> x (Const32 [c])) => (Lsh64x64  x (Const64 <t> [int64(uint32(c))]))
   358  (Lsh64x16  <t> x (Const16 [c])) => (Lsh64x64  x (Const64 <t> [int64(uint16(c))]))
   359  (Lsh64x8   <t> x (Const8  [c])) => (Lsh64x64  x (Const64 <t> [int64(uint8(c))]))
   360  (Rsh64x32  <t> x (Const32 [c])) => (Rsh64x64  x (Const64 <t> [int64(uint32(c))]))
   361  (Rsh64x16  <t> x (Const16 [c])) => (Rsh64x64  x (Const64 <t> [int64(uint16(c))]))
   362  (Rsh64x8   <t> x (Const8  [c])) => (Rsh64x64  x (Const64 <t> [int64(uint8(c))]))
   363  (Rsh64Ux32 <t> x (Const32 [c])) => (Rsh64Ux64 x (Const64 <t> [int64(uint32(c))]))
   364  (Rsh64Ux16 <t> x (Const16 [c])) => (Rsh64Ux64 x (Const64 <t> [int64(uint16(c))]))
   365  (Rsh64Ux8  <t> x (Const8  [c])) => (Rsh64Ux64 x (Const64 <t> [int64(uint8(c))]))
   366  
   367  (Lsh32x32  <t> x (Const32 [c])) => (Lsh32x64  x (Const64 <t> [int64(uint32(c))]))
   368  (Lsh32x16  <t> x (Const16 [c])) => (Lsh32x64  x (Const64 <t> [int64(uint16(c))]))
   369  (Lsh32x8   <t> x (Const8  [c])) => (Lsh32x64  x (Const64 <t> [int64(uint8(c))]))
   370  (Rsh32x32  <t> x (Const32 [c])) => (Rsh32x64  x (Const64 <t> [int64(uint32(c))]))
   371  (Rsh32x16  <t> x (Const16 [c])) => (Rsh32x64  x (Const64 <t> [int64(uint16(c))]))
   372  (Rsh32x8   <t> x (Const8  [c])) => (Rsh32x64  x (Const64 <t> [int64(uint8(c))]))
   373  (Rsh32Ux32 <t> x (Const32 [c])) => (Rsh32Ux64 x (Const64 <t> [int64(uint32(c))]))
   374  (Rsh32Ux16 <t> x (Const16 [c])) => (Rsh32Ux64 x (Const64 <t> [int64(uint16(c))]))
   375  (Rsh32Ux8  <t> x (Const8  [c])) => (Rsh32Ux64 x (Const64 <t> [int64(uint8(c))]))
   376  
   377  (Lsh16x32  <t> x (Const32 [c])) => (Lsh16x64  x (Const64 <t> [int64(uint32(c))]))
   378  (Lsh16x16  <t> x (Const16 [c])) => (Lsh16x64  x (Const64 <t> [int64(uint16(c))]))
   379  (Lsh16x8   <t> x (Const8  [c])) => (Lsh16x64  x (Const64 <t> [int64(uint8(c))]))
   380  (Rsh16x32  <t> x (Const32 [c])) => (Rsh16x64  x (Const64 <t> [int64(uint32(c))]))
   381  (Rsh16x16  <t> x (Const16 [c])) => (Rsh16x64  x (Const64 <t> [int64(uint16(c))]))
   382  (Rsh16x8   <t> x (Const8  [c])) => (Rsh16x64  x (Const64 <t> [int64(uint8(c))]))
   383  (Rsh16Ux32 <t> x (Const32 [c])) => (Rsh16Ux64 x (Const64 <t> [int64(uint32(c))]))
   384  (Rsh16Ux16 <t> x (Const16 [c])) => (Rsh16Ux64 x (Const64 <t> [int64(uint16(c))]))
   385  (Rsh16Ux8  <t> x (Const8  [c])) => (Rsh16Ux64 x (Const64 <t> [int64(uint8(c))]))
   386  
   387  (Lsh8x32  <t> x (Const32 [c])) => (Lsh8x64  x (Const64 <t> [int64(uint32(c))]))
   388  (Lsh8x16  <t> x (Const16 [c])) => (Lsh8x64  x (Const64 <t> [int64(uint16(c))]))
   389  (Lsh8x8   <t> x (Const8  [c])) => (Lsh8x64  x (Const64 <t> [int64(uint8(c))]))
   390  (Rsh8x32  <t> x (Const32 [c])) => (Rsh8x64  x (Const64 <t> [int64(uint32(c))]))
   391  (Rsh8x16  <t> x (Const16 [c])) => (Rsh8x64  x (Const64 <t> [int64(uint16(c))]))
   392  (Rsh8x8   <t> x (Const8  [c])) => (Rsh8x64  x (Const64 <t> [int64(uint8(c))]))
   393  (Rsh8Ux32 <t> x (Const32 [c])) => (Rsh8Ux64 x (Const64 <t> [int64(uint32(c))]))
   394  (Rsh8Ux16 <t> x (Const16 [c])) => (Rsh8Ux64 x (Const64 <t> [int64(uint16(c))]))
   395  (Rsh8Ux8  <t> x (Const8  [c])) => (Rsh8Ux64 x (Const64 <t> [int64(uint8(c))]))
   396  
   397  // shifts by zero
   398  (Lsh(64|32|16|8)x64  x (Const64 [0])) => x
   399  (Rsh(64|32|16|8)x64  x (Const64 [0])) => x
   400  (Rsh(64|32|16|8)Ux64 x (Const64 [0])) => x
   401  
   402  // rotates by multiples of register width
   403  (RotateLeft64 x (Const64 [c])) && c%64 == 0 => x
   404  (RotateLeft32 x (Const32 [c])) && c%32 == 0 => x
   405  (RotateLeft16 x (Const16 [c])) && c%16 == 0 => x
   406  (RotateLeft8  x (Const8 [c]))  && c%8  == 0 => x
   407  
   408  // zero shifted
   409  (Lsh64x(64|32|16|8)  (Const64 [0]) _) => (Const64 [0])
   410  (Rsh64x(64|32|16|8)  (Const64 [0]) _) => (Const64 [0])
   411  (Rsh64Ux(64|32|16|8) (Const64 [0]) _) => (Const64 [0])
   412  (Lsh32x(64|32|16|8)  (Const32 [0]) _) => (Const32 [0])
   413  (Rsh32x(64|32|16|8)  (Const32 [0]) _) => (Const32 [0])
   414  (Rsh32Ux(64|32|16|8) (Const32 [0]) _) => (Const32 [0])
   415  (Lsh16x(64|32|16|8)  (Const16 [0]) _) => (Const16 [0])
   416  (Rsh16x(64|32|16|8)  (Const16 [0]) _) => (Const16 [0])
   417  (Rsh16Ux(64|32|16|8) (Const16 [0]) _) => (Const16 [0])
   418  (Lsh8x(64|32|16|8)   (Const8  [0]) _) => (Const8  [0])
   419  (Rsh8x(64|32|16|8)   (Const8  [0]) _) => (Const8  [0])
   420  (Rsh8Ux(64|32|16|8)  (Const8  [0]) _) => (Const8  [0])
   421  
   422  // large left shifts of all values, and right shifts of unsigned values
   423  ((Lsh64|Rsh64U)x64  _ (Const64 [c])) && uint64(c) >= 64 => (Const64 [0])
   424  ((Lsh32|Rsh32U)x64  _ (Const64 [c])) && uint64(c) >= 32 => (Const32 [0])
   425  ((Lsh16|Rsh16U)x64  _ (Const64 [c])) && uint64(c) >= 16 => (Const16 [0])
   426  ((Lsh8|Rsh8U)x64    _ (Const64 [c])) && uint64(c) >= 8  => (Const8  [0])
   427  
   428  // combine const shifts
   429  (Lsh64x64 <t> (Lsh64x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh64x64 x (Const64 <t> [c+d]))
   430  (Lsh32x64 <t> (Lsh32x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh32x64 x (Const64 <t> [c+d]))
   431  (Lsh16x64 <t> (Lsh16x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh16x64 x (Const64 <t> [c+d]))
   432  (Lsh8x64  <t> (Lsh8x64  x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Lsh8x64  x (Const64 <t> [c+d]))
   433  
   434  (Rsh64x64 <t> (Rsh64x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh64x64 x (Const64 <t> [c+d]))
   435  (Rsh32x64 <t> (Rsh32x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh32x64 x (Const64 <t> [c+d]))
   436  (Rsh16x64 <t> (Rsh16x64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh16x64 x (Const64 <t> [c+d]))
   437  (Rsh8x64  <t> (Rsh8x64  x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh8x64  x (Const64 <t> [c+d]))
   438  
   439  (Rsh64Ux64 <t> (Rsh64Ux64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh64Ux64 x (Const64 <t> [c+d]))
   440  (Rsh32Ux64 <t> (Rsh32Ux64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh32Ux64 x (Const64 <t> [c+d]))
   441  (Rsh16Ux64 <t> (Rsh16Ux64 x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh16Ux64 x (Const64 <t> [c+d]))
   442  (Rsh8Ux64  <t> (Rsh8Ux64  x (Const64 [c])) (Const64 [d])) && !uaddOvf(c,d) => (Rsh8Ux64  x (Const64 <t> [c+d]))
   443  
   444  // Remove signed right shift before an unsigned right shift that extracts the sign bit.
   445  (Rsh8Ux64  (Rsh8x64  x _) (Const64 <t> [7] )) => (Rsh8Ux64  x (Const64 <t> [7] ))
   446  (Rsh16Ux64 (Rsh16x64 x _) (Const64 <t> [15])) => (Rsh16Ux64 x (Const64 <t> [15]))
   447  (Rsh32Ux64 (Rsh32x64 x _) (Const64 <t> [31])) => (Rsh32Ux64 x (Const64 <t> [31]))
   448  (Rsh64Ux64 (Rsh64x64 x _) (Const64 <t> [63])) => (Rsh64Ux64 x (Const64 <t> [63]))
   449  
   450  // Convert x>>c<<c to x&^(1<<c-1)
   451  (Lsh64x64 i:(Rsh(64|64U)x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 64 && i.Uses == 1 => (And64 x (Const64 <v.Type> [int64(-1) << c]))
   452  (Lsh32x64 i:(Rsh(32|32U)x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 32 && i.Uses == 1 => (And32 x (Const32 <v.Type> [int32(-1) << c]))
   453  (Lsh16x64 i:(Rsh(16|16U)x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 16 && i.Uses == 1 => (And16 x (Const16 <v.Type> [int16(-1) << c]))
   454  (Lsh8x64  i:(Rsh(8|8U)x64    x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 8  && i.Uses == 1 => (And8  x (Const8  <v.Type> [int8(-1)  << c]))
   455  // similarly for x<<c>>c
   456  (Rsh64Ux64 i:(Lsh64x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 64 && i.Uses == 1 => (And64 x (Const64 <v.Type> [int64(^uint64(0)>>c)]))
   457  (Rsh32Ux64 i:(Lsh32x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 32 && i.Uses == 1 => (And32 x (Const32 <v.Type> [int32(^uint32(0)>>c)]))
   458  (Rsh16Ux64 i:(Lsh16x64 x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 16 && i.Uses == 1 => (And16 x (Const16 <v.Type> [int16(^uint16(0)>>c)]))
   459  (Rsh8Ux64  i:(Lsh8x64  x (Const64 [c])) (Const64 [c])) && c >= 0 && c < 8  && i.Uses == 1 => (And8  x (Const8  <v.Type> [int8 (^uint8 (0)>>c)]))
   460  
   461  // ((x >> c1) << c2) >> c3
   462  (Rsh(64|32|16|8)Ux64 (Lsh(64|32|16|8)x64 (Rsh(64|32|16|8)Ux64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
   463    && uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
   464    => (Rsh(64|32|16|8)Ux64 x (Const64 <typ.UInt64> [c1-c2+c3]))
   465  
   466  // ((x << c1) >> c2) << c3
   467  (Lsh(64|32|16|8)x64 (Rsh(64|32|16|8)Ux64 (Lsh(64|32|16|8)x64 x (Const64 [c1])) (Const64 [c2])) (Const64 [c3]))
   468    && uint64(c1) >= uint64(c2) && uint64(c3) >= uint64(c2) && !uaddOvf(c1-c2, c3)
   469    => (Lsh(64|32|16|8)x64 x (Const64 <typ.UInt64> [c1-c2+c3]))
   470  
   471  // (x >> c) & uppermask = 0
   472  (And64 (Const64 [m]) (Rsh64Ux64 _ (Const64 [c]))) && c >= int64(64-ntz64(m)) => (Const64 [0])
   473  (And32 (Const32 [m]) (Rsh32Ux64 _ (Const64 [c]))) && c >= int64(32-ntz32(m)) => (Const32 [0])
   474  (And16 (Const16 [m]) (Rsh16Ux64 _ (Const64 [c]))) && c >= int64(16-ntz16(m)) => (Const16 [0])
   475  (And8  (Const8  [m]) (Rsh8Ux64  _ (Const64 [c]))) && c >= int64(8-ntz8(m))  => (Const8  [0])
   476  
   477  // (x << c) & lowermask = 0
   478  (And64 (Const64 [m]) (Lsh64x64  _ (Const64 [c]))) && c >= int64(64-nlz64(m)) => (Const64 [0])
   479  (And32 (Const32 [m]) (Lsh32x64  _ (Const64 [c]))) && c >= int64(32-nlz32(m)) => (Const32 [0])
   480  (And16 (Const16 [m]) (Lsh16x64  _ (Const64 [c]))) && c >= int64(16-nlz16(m)) => (Const16 [0])
   481  (And8  (Const8  [m]) (Lsh8x64   _ (Const64 [c]))) && c >= int64(8-nlz8(m))  => (Const8  [0])
   482  
   483  // replace shifts with zero extensions
   484  (Rsh16Ux64 (Lsh16x64 x (Const64  [8])) (Const64  [8])) => (ZeroExt8to16  (Trunc16to8  <typ.UInt8>  x))
   485  (Rsh32Ux64 (Lsh32x64 x (Const64 [24])) (Const64 [24])) => (ZeroExt8to32  (Trunc32to8  <typ.UInt8>  x))
   486  (Rsh64Ux64 (Lsh64x64 x (Const64 [56])) (Const64 [56])) => (ZeroExt8to64  (Trunc64to8  <typ.UInt8>  x))
   487  (Rsh32Ux64 (Lsh32x64 x (Const64 [16])) (Const64 [16])) => (ZeroExt16to32 (Trunc32to16 <typ.UInt16> x))
   488  (Rsh64Ux64 (Lsh64x64 x (Const64 [48])) (Const64 [48])) => (ZeroExt16to64 (Trunc64to16 <typ.UInt16> x))
   489  (Rsh64Ux64 (Lsh64x64 x (Const64 [32])) (Const64 [32])) => (ZeroExt32to64 (Trunc64to32 <typ.UInt32> x))
   490  
   491  // replace shifts with sign extensions
   492  (Rsh16x64 (Lsh16x64 x (Const64  [8])) (Const64  [8])) => (SignExt8to16  (Trunc16to8  <typ.Int8>  x))
   493  (Rsh32x64 (Lsh32x64 x (Const64 [24])) (Const64 [24])) => (SignExt8to32  (Trunc32to8  <typ.Int8>  x))
   494  (Rsh64x64 (Lsh64x64 x (Const64 [56])) (Const64 [56])) => (SignExt8to64  (Trunc64to8  <typ.Int8>  x))
   495  (Rsh32x64 (Lsh32x64 x (Const64 [16])) (Const64 [16])) => (SignExt16to32 (Trunc32to16 <typ.Int16> x))
   496  (Rsh64x64 (Lsh64x64 x (Const64 [48])) (Const64 [48])) => (SignExt16to64 (Trunc64to16 <typ.Int16> x))
   497  (Rsh64x64 (Lsh64x64 x (Const64 [32])) (Const64 [32])) => (SignExt32to64 (Trunc64to32 <typ.Int32> x))
   498  
   499  // constant comparisons
   500  (Eq(64|32|16|8)   (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c == d])
   501  (Neq(64|32|16|8)  (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c != d])
   502  (Less(64|32|16|8) (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c < d])
   503  (Leq(64|32|16|8)  (Const(64|32|16|8) [c]) (Const(64|32|16|8) [d])) => (ConstBool [c <= d])
   504  
   505  (Less64U (Const64 [c]) (Const64 [d])) => (ConstBool [uint64(c) < uint64(d)])
   506  (Less32U (Const32 [c]) (Const32 [d])) => (ConstBool [uint32(c) < uint32(d)])
   507  (Less16U (Const16 [c]) (Const16 [d])) => (ConstBool [uint16(c) < uint16(d)])
   508  (Less8U  (Const8  [c]) (Const8  [d])) => (ConstBool [ uint8(c) <  uint8(d)])
   509  
   510  (Leq64U (Const64 [c]) (Const64 [d])) => (ConstBool [uint64(c) <= uint64(d)])
   511  (Leq32U (Const32 [c]) (Const32 [d])) => (ConstBool [uint32(c) <= uint32(d)])
   512  (Leq16U (Const16 [c]) (Const16 [d])) => (ConstBool [uint16(c) <= uint16(d)])
   513  (Leq8U  (Const8  [c]) (Const8  [d])) => (ConstBool [ uint8(c) <=  uint8(d)])
   514  
   515  (Leq8  (Const8  [0]) (And8  _ (Const8  [c]))) && c >= 0 => (ConstBool [true])
   516  (Leq16 (Const16 [0]) (And16 _ (Const16 [c]))) && c >= 0 => (ConstBool [true])
   517  (Leq32 (Const32 [0]) (And32 _ (Const32 [c]))) && c >= 0 => (ConstBool [true])
   518  (Leq64 (Const64 [0]) (And64 _ (Const64 [c]))) && c >= 0 => (ConstBool [true])
   519  
   520  (Leq8  (Const8  [0]) (Rsh8Ux64  _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   521  (Leq16 (Const16 [0]) (Rsh16Ux64 _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   522  (Leq32 (Const32 [0]) (Rsh32Ux64 _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   523  (Leq64 (Const64 [0]) (Rsh64Ux64 _ (Const64 [c]))) && c > 0 => (ConstBool [true])
   524  
   525  // prefer equalities with zero
   526  (Less(64|32|16|8) (Const(64|32|16|8) <t> [0]) x) && isNonNegative(x) => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   527  (Less(64|32|16|8) x (Const(64|32|16|8) <t> [1])) && isNonNegative(x) => (Eq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   528  (Less(64|32|16|8)U x (Const(64|32|16|8) <t> [1])) => (Eq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   529  (Leq(64|32|16|8)U (Const(64|32|16|8) <t> [1]) x) => (Neq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   530  
   531  // prefer comparisons with zero
   532  (Less(64|32|16|8) x (Const(64|32|16|8) <t> [1])) => (Leq(64|32|16|8) x (Const(64|32|16|8) <t> [0]))
   533  (Leq(64|32|16|8) x (Const(64|32|16|8) <t> [-1])) => (Less(64|32|16|8) x (Const(64|32|16|8) <t> [0]))
   534  (Leq(64|32|16|8) (Const(64|32|16|8) <t> [1]) x) => (Less(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   535  (Less(64|32|16|8) (Const(64|32|16|8) <t> [-1]) x) => (Leq(64|32|16|8) (Const(64|32|16|8) <t> [0]) x)
   536  
   537  // constant floating point comparisons
   538  (Eq32F   (Const32F [c]) (Const32F [d])) => (ConstBool [c == d])
   539  (Eq64F   (Const64F [c]) (Const64F [d])) => (ConstBool [c == d])
   540  (Neq32F  (Const32F [c]) (Const32F [d])) => (ConstBool [c != d])
   541  (Neq64F  (Const64F [c]) (Const64F [d])) => (ConstBool [c != d])
   542  (Less32F (Const32F [c]) (Const32F [d])) => (ConstBool [c < d])
   543  (Less64F (Const64F [c]) (Const64F [d])) => (ConstBool [c < d])
   544  (Leq32F  (Const32F [c]) (Const32F [d])) => (ConstBool [c <= d])
   545  (Leq64F  (Const64F [c]) (Const64F [d])) => (ConstBool [c <= d])
   546  
   547  // simplifications
   548  (Or(64|32|16|8) x x) => x
   549  (Or(64|32|16|8) (Const(64|32|16|8)  [0]) x) => x
   550  (Or(64|32|16|8) (Const(64|32|16|8) [-1]) _) => (Const(64|32|16|8) [-1])
   551  (Or(64|32|16|8) (Com(64|32|16|8)     x)  x) => (Const(64|32|16|8) [-1])
   552  
   553  (And(64|32|16|8) x x) => x
   554  (And(64|32|16|8) (Const(64|32|16|8) [-1]) x) => x
   555  (And(64|32|16|8) (Const(64|32|16|8)  [0]) _) => (Const(64|32|16|8) [0])
   556  (And(64|32|16|8) (Com(64|32|16|8)     x)  x) => (Const(64|32|16|8) [0])
   557  
   558  (Xor(64|32|16|8) x x) => (Const(64|32|16|8) [0])
   559  (Xor(64|32|16|8) (Const(64|32|16|8) [0]) x) => x
   560  (Xor(64|32|16|8) (Com(64|32|16|8)    x)  x) => (Const(64|32|16|8) [-1])
   561  
   562  (Add(64|32|16|8) (Const(64|32|16|8) [0]) x) => x
   563  (Sub(64|32|16|8) x x) => (Const(64|32|16|8) [0])
   564  (Mul(64|32|16|8) (Const(64|32|16|8) [0]) _) => (Const(64|32|16|8) [0])
   565  (Select0 (Mul(64|32)uover (Const(64|32) [0]) x)) => (Const(64|32) [0])
   566  (Select1 (Mul(64|32)uover (Const(64|32) [0]) x)) => (ConstBool [false])
   567  
   568  (Com(64|32|16|8) (Com(64|32|16|8)  x)) => x
   569  (Com(64|32|16|8) (Const(64|32|16|8) [c])) => (Const(64|32|16|8) [^c])
   570  
   571  (Neg(64|32|16|8) (Sub(64|32|16|8) x y)) => (Sub(64|32|16|8) y x)
   572  (Add(64|32|16|8) x (Neg(64|32|16|8) y)) => (Sub(64|32|16|8) x y)
   573  
   574  (Xor(64|32|16|8) (Const(64|32|16|8) [-1]) x) => (Com(64|32|16|8) x)
   575  
   576  (Sub(64|32|16|8) (Neg(64|32|16|8) x) (Com(64|32|16|8) x)) => (Const(64|32|16|8) [1])
   577  (Sub(64|32|16|8) (Com(64|32|16|8) x) (Neg(64|32|16|8) x)) => (Const(64|32|16|8) [-1])
   578  (Add(64|32|16|8) (Com(64|32|16|8) x)                  x)  => (Const(64|32|16|8) [-1])
   579  
   580  // Simplification when involving common integer
   581  // (t + x) - (t + y) == x - y
   582  // (t + x) - (y + t) == x - y
   583  // (x + t) - (y + t) == x - y
   584  // (x + t) - (t + y) == x - y
   585  // (x - t) + (t + y) == x + y
   586  // (x - t) + (y + t) == x + y
   587  (Sub(64|32|16|8) (Add(64|32|16|8) t x) (Add(64|32|16|8) t y)) => (Sub(64|32|16|8) x y)
   588  (Add(64|32|16|8) (Sub(64|32|16|8) x t) (Add(64|32|16|8) t y)) => (Add(64|32|16|8) x y)
   589  
   590  // ^(x-1) == ^x+1 == -x
   591  (Add(64|32|16|8) (Const(64|32|16|8) [1]) (Com(64|32|16|8) x)) => (Neg(64|32|16|8) x)
   592  (Com(64|32|16|8) (Add(64|32|16|8) (Const(64|32|16|8) [-1]) x)) => (Neg(64|32|16|8) x)
   593  
   594  // -(-x) == x
   595  (Neg(64|32|16|8) (Neg(64|32|16|8) x)) => x
   596  
   597  // -^x == x+1
   598  (Neg(64|32|16|8) <t> (Com(64|32|16|8) x)) => (Add(64|32|16|8) (Const(64|32|16|8) <t> [1]) x)
   599  
   600  (And(64|32|16|8) x (And(64|32|16|8) x y)) => (And(64|32|16|8) x y)
   601  (Or(64|32|16|8) x (Or(64|32|16|8) x y)) => (Or(64|32|16|8) x y)
   602  (Xor(64|32|16|8) x (Xor(64|32|16|8) x y)) => y
   603  
   604  // Fold comparisons with numeric bounds
   605  (Less(64|32|16|8)U _ (Const(64|32|16|8) [0]))  => (ConstBool [false])
   606  (Leq(64|32|16|8)U (Const(64|32|16|8) [0]) _)   => (ConstBool [true])
   607  (Less(64|32|16|8)U (Const(64|32|16|8) [-1]) _) => (ConstBool [false])
   608  (Leq(64|32|16|8)U _ (Const(64|32|16|8) [-1]))  => (ConstBool [true])
   609  (Less64 _ (Const64 [math.MinInt64])) => (ConstBool [false])
   610  (Less32 _ (Const32 [math.MinInt32])) => (ConstBool [false])
   611  (Less16 _ (Const16 [math.MinInt16])) => (ConstBool [false])
   612  (Less8  _ (Const8  [math.MinInt8 ])) => (ConstBool [false])
   613  (Leq64 (Const64 [math.MinInt64]) _)  => (ConstBool [true])
   614  (Leq32 (Const32 [math.MinInt32]) _)  => (ConstBool [true])
   615  (Leq16 (Const16 [math.MinInt16]) _)  => (ConstBool [true])
   616  (Leq8  (Const8  [math.MinInt8 ]) _)  => (ConstBool [true])
   617  (Less64 (Const64 [math.MaxInt64]) _) => (ConstBool [false])
   618  (Less32 (Const32 [math.MaxInt32]) _) => (ConstBool [false])
   619  (Less16 (Const16 [math.MaxInt16]) _) => (ConstBool [false])
   620  (Less8  (Const8  [math.MaxInt8 ]) _) => (ConstBool [false])
   621  (Leq64 _ (Const64 [math.MaxInt64]))  => (ConstBool [true])
   622  (Leq32 _ (Const32 [math.MaxInt32]))  => (ConstBool [true])
   623  (Leq16 _ (Const16 [math.MaxInt16]))  => (ConstBool [true])
   624  (Leq8  _ (Const8  [math.MaxInt8 ]))  => (ConstBool [true])
   625  
   626  // Canonicalize <= on numeric bounds and < near numeric bounds to ==
   627  (Leq(64|32|16|8)U x c:(Const(64|32|16|8) [0]))     => (Eq(64|32|16|8) x c)
   628  (Leq(64|32|16|8)U c:(Const(64|32|16|8) [-1]) x)    => (Eq(64|32|16|8) x c)
   629  (Less(64|32|16|8)U x (Const(64|32|16|8) <t> [1]))  => (Eq(64|32|16|8) x (Const(64|32|16|8) <t> [0]))
   630  (Less(64|32|16|8)U (Const(64|32|16|8) <t> [-2]) x) => (Eq(64|32|16|8) x (Const(64|32|16|8) <t> [-1]))
   631  (Leq64 x c:(Const64 [math.MinInt64])) => (Eq64 x c)
   632  (Leq32 x c:(Const32 [math.MinInt32])) => (Eq32 x c)
   633  (Leq16 x c:(Const16 [math.MinInt16])) => (Eq16 x c)
   634  (Leq8  x c:(Const8  [math.MinInt8 ])) => (Eq8  x c)
   635  (Leq64 c:(Const64 [math.MaxInt64]) x) => (Eq64 x c)
   636  (Leq32 c:(Const32 [math.MaxInt32]) x) => (Eq32 x c)
   637  (Leq16 c:(Const16 [math.MaxInt16]) x) => (Eq16 x c)
   638  (Leq8  c:(Const8  [math.MaxInt8 ]) x) => (Eq8  x c)
   639  (Less64 x (Const64 <t> [math.MinInt64+1])) => (Eq64 x (Const64 <t> [math.MinInt64]))
   640  (Less32 x (Const32 <t> [math.MinInt32+1])) => (Eq32 x (Const32 <t> [math.MinInt32]))
   641  (Less16 x (Const16 <t> [math.MinInt16+1])) => (Eq16 x (Const16 <t> [math.MinInt16]))
   642  (Less8  x (Const8  <t> [math.MinInt8 +1])) => (Eq8  x (Const8  <t> [math.MinInt8 ]))
   643  (Less64 (Const64 <t> [math.MaxInt64-1]) x) => (Eq64 x (Const64 <t> [math.MaxInt64]))
   644  (Less32 (Const32 <t> [math.MaxInt32-1]) x) => (Eq32 x (Const32 <t> [math.MaxInt32]))
   645  (Less16 (Const16 <t> [math.MaxInt16-1]) x) => (Eq16 x (Const16 <t> [math.MaxInt16]))
   646  (Less8  (Const8  <t> [math.MaxInt8 -1]) x) => (Eq8  x (Const8  <t> [math.MaxInt8 ]))
   647  
   648  // Ands clear bits. Ors set bits.
   649  // If a subsequent Or will set all the bits
   650  // that an And cleared, we can skip the And.
   651  // This happens in bitmasking code like:
   652  //   x &^= 3 << shift // clear two old bits
   653  //   x  |= v << shift // set two new bits
   654  // when shift is a small constant and v ends up a constant 3.
   655  (Or8  (And8  x (Const8  [c2])) (Const8  <t> [c1])) && ^(c1 | c2) == 0 => (Or8  (Const8  <t> [c1]) x)
   656  (Or16 (And16 x (Const16 [c2])) (Const16 <t> [c1])) && ^(c1 | c2) == 0 => (Or16 (Const16 <t> [c1]) x)
   657  (Or32 (And32 x (Const32 [c2])) (Const32 <t> [c1])) && ^(c1 | c2) == 0 => (Or32 (Const32 <t> [c1]) x)
   658  (Or64 (And64 x (Const64 [c2])) (Const64 <t> [c1])) && ^(c1 | c2) == 0 => (Or64 (Const64 <t> [c1]) x)
   659  
   660  (Trunc64to8  (And64 (Const64 [y]) x)) && y&0xFF == 0xFF => (Trunc64to8 x)
   661  (Trunc64to16 (And64 (Const64 [y]) x)) && y&0xFFFF == 0xFFFF => (Trunc64to16 x)
   662  (Trunc64to32 (And64 (Const64 [y]) x)) && y&0xFFFFFFFF == 0xFFFFFFFF => (Trunc64to32 x)
   663  (Trunc32to8  (And32 (Const32 [y]) x)) && y&0xFF == 0xFF => (Trunc32to8 x)
   664  (Trunc32to16 (And32 (Const32 [y]) x)) && y&0xFFFF == 0xFFFF => (Trunc32to16 x)
   665  (Trunc16to8  (And16 (Const16 [y]) x)) && y&0xFF == 0xFF => (Trunc16to8 x)
   666  
   667  (ZeroExt8to64  (Trunc64to8  x:(Rsh64Ux64 _ (Const64 [s])))) && s >= 56 => x
   668  (ZeroExt16to64 (Trunc64to16 x:(Rsh64Ux64 _ (Const64 [s])))) && s >= 48 => x
   669  (ZeroExt32to64 (Trunc64to32 x:(Rsh64Ux64 _ (Const64 [s])))) && s >= 32 => x
   670  (ZeroExt8to32  (Trunc32to8  x:(Rsh32Ux64 _ (Const64 [s])))) && s >= 24 => x
   671  (ZeroExt16to32 (Trunc32to16 x:(Rsh32Ux64 _ (Const64 [s])))) && s >= 16 => x
   672  (ZeroExt8to16  (Trunc16to8  x:(Rsh16Ux64 _ (Const64 [s])))) && s >= 8 => x
   673  
   674  (SignExt8to64  (Trunc64to8  x:(Rsh64x64 _ (Const64 [s])))) && s >= 56 => x
   675  (SignExt16to64 (Trunc64to16 x:(Rsh64x64 _ (Const64 [s])))) && s >= 48 => x
   676  (SignExt32to64 (Trunc64to32 x:(Rsh64x64 _ (Const64 [s])))) && s >= 32 => x
   677  (SignExt8to32  (Trunc32to8  x:(Rsh32x64 _ (Const64 [s])))) && s >= 24 => x
   678  (SignExt16to32 (Trunc32to16 x:(Rsh32x64 _ (Const64 [s])))) && s >= 16 => x
   679  (SignExt8to16  (Trunc16to8  x:(Rsh16x64 _ (Const64 [s])))) && s >= 8 => x
   680  
   681  (Slicemask (Const32 [x])) && x > 0 => (Const32 [-1])
   682  (Slicemask (Const32 [0]))          => (Const32 [0])
   683  (Slicemask (Const64 [x])) && x > 0 => (Const64 [-1])
   684  (Slicemask (Const64 [0]))          => (Const64 [0])
   685  
   686  // simplifications often used for lengths.  e.g. len(s[i:i+5])==5
   687  (Sub(64|32|16|8) (Add(64|32|16|8) x y) x) => y
   688  (Sub(64|32|16|8) (Add(64|32|16|8) x y) y) => x
   689  (Sub(64|32|16|8) (Sub(64|32|16|8) x y) x) => (Neg(64|32|16|8) y)
   690  (Sub(64|32|16|8) x (Add(64|32|16|8) x y)) => (Neg(64|32|16|8) y)
   691  (Add(64|32|16|8) x (Sub(64|32|16|8) y x)) => y
   692  (Add(64|32|16|8) x (Add(64|32|16|8) y (Sub(64|32|16|8) z x))) => (Add(64|32|16|8) y z)
   693  
   694  // basic phi simplifications
   695  (Phi (Const8  [c]) (Const8  [c])) => (Const8  [c])
   696  (Phi (Const16 [c]) (Const16 [c])) => (Const16 [c])
   697  (Phi (Const32 [c]) (Const32 [c])) => (Const32 [c])
   698  (Phi (Const64 [c]) (Const64 [c])) => (Const64 [c])
   699  
   700  // slice and interface comparisons
   701  // The frontend ensures that we can only compare against nil,
   702  // so we need only compare the first word (interface type or slice ptr).
   703  (EqInter x y)  => (EqPtr  (ITab x) (ITab y))
   704  (NeqInter x y) => (NeqPtr (ITab x) (ITab y))
   705  (EqSlice x y)  => (EqPtr  (SlicePtr x) (SlicePtr y))
   706  (NeqSlice x y) => (NeqPtr (SlicePtr x) (SlicePtr y))
   707  
   708  // Load of store of same address, with compatibly typed value and same size
   709  (Load <t1> p1 (Store {t2} p2 x _))
   710  	&& isSamePtr(p1, p2)
   711  	&& t1.Compare(x.Type) == types.CMPeq
   712  	&& t1.Size() == t2.Size()
   713  	=> x
   714  (Load <t1> p1 (Store {t2} p2 _ (Store {t3} p3 x _)))
   715  	&& isSamePtr(p1, p3)
   716  	&& t1.Compare(x.Type) == types.CMPeq
   717  	&& t1.Size() == t2.Size()
   718  	&& disjoint(p3, t3.Size(), p2, t2.Size())
   719  	=> x
   720  (Load <t1> p1 (Store {t2} p2 _ (Store {t3} p3 _ (Store {t4} p4 x _))))
   721  	&& isSamePtr(p1, p4)
   722  	&& t1.Compare(x.Type) == types.CMPeq
   723  	&& t1.Size() == t2.Size()
   724  	&& disjoint(p4, t4.Size(), p2, t2.Size())
   725  	&& disjoint(p4, t4.Size(), p3, t3.Size())
   726  	=> x
   727  (Load <t1> p1 (Store {t2} p2 _ (Store {t3} p3 _ (Store {t4} p4 _ (Store {t5} p5 x _)))))
   728  	&& isSamePtr(p1, p5)
   729  	&& t1.Compare(x.Type) == types.CMPeq
   730  	&& t1.Size() == t2.Size()
   731  	&& disjoint(p5, t5.Size(), p2, t2.Size())
   732  	&& disjoint(p5, t5.Size(), p3, t3.Size())
   733  	&& disjoint(p5, t5.Size(), p4, t4.Size())
   734  	=> x
   735  
   736  // Pass constants through math.Float{32,64}bits and math.Float{32,64}frombits
   737  (Load <t1> p1 (Store {t2} p2 (Const64  [x]) _)) && isSamePtr(p1,p2) && sizeof(t2) == 8 && is64BitFloat(t1) && !math.IsNaN(math.Float64frombits(uint64(x))) => (Const64F [math.Float64frombits(uint64(x))])
   738  (Load <t1> p1 (Store {t2} p2 (Const32  [x]) _)) && isSamePtr(p1,p2) && sizeof(t2) == 4 && is32BitFloat(t1) && !math.IsNaN(float64(math.Float32frombits(uint32(x)))) => (Const32F [math.Float32frombits(uint32(x))])
   739  (Load <t1> p1 (Store {t2} p2 (Const64F [x]) _)) && isSamePtr(p1,p2) && sizeof(t2) == 8 && is64BitInt(t1)   => (Const64  [int64(math.Float64bits(x))])
   740  (Load <t1> p1 (Store {t2} p2 (Const32F [x]) _)) && isSamePtr(p1,p2) && sizeof(t2) == 4 && is32BitInt(t1)   => (Const32  [int32(math.Float32bits(x))])
   741  
   742  // Float Loads up to Zeros so they can be constant folded.
   743  (Load <t1> op:(OffPtr [o1] p1)
   744  	(Store {t2} p2 _
   745  		mem:(Zero [n] p3 _)))
   746  	&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p3)
   747  	&& CanSSA(t1)
   748  	&& disjoint(op, t1.Size(), p2, t2.Size())
   749  	=> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p3) mem)
   750  (Load <t1> op:(OffPtr [o1] p1)
   751  	(Store {t2} p2 _
   752  		(Store {t3} p3 _
   753  			mem:(Zero [n] p4 _))))
   754  	&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p4)
   755  	&& CanSSA(t1)
   756  	&& disjoint(op, t1.Size(), p2, t2.Size())
   757  	&& disjoint(op, t1.Size(), p3, t3.Size())
   758  	=> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p4) mem)
   759  (Load <t1> op:(OffPtr [o1] p1)
   760  	(Store {t2} p2 _
   761  		(Store {t3} p3 _
   762  			(Store {t4} p4 _
   763  				mem:(Zero [n] p5 _)))))
   764  	&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p5)
   765  	&& CanSSA(t1)
   766  	&& disjoint(op, t1.Size(), p2, t2.Size())
   767  	&& disjoint(op, t1.Size(), p3, t3.Size())
   768  	&& disjoint(op, t1.Size(), p4, t4.Size())
   769  	=> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p5) mem)
   770  (Load <t1> op:(OffPtr [o1] p1)
   771  	(Store {t2} p2 _
   772  		(Store {t3} p3 _
   773  			(Store {t4} p4 _
   774  				(Store {t5} p5 _
   775  					mem:(Zero [n] p6 _))))))
   776  	&& o1 >= 0 && o1+t1.Size() <= n && isSamePtr(p1, p6)
   777  	&& CanSSA(t1)
   778  	&& disjoint(op, t1.Size(), p2, t2.Size())
   779  	&& disjoint(op, t1.Size(), p3, t3.Size())
   780  	&& disjoint(op, t1.Size(), p4, t4.Size())
   781  	&& disjoint(op, t1.Size(), p5, t5.Size())
   782  	=> @mem.Block (Load <t1> (OffPtr <op.Type> [o1] p6) mem)
   783  
   784  // Zero to Load forwarding.
   785  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   786  	&& t1.IsBoolean()
   787  	&& isSamePtr(p1, p2)
   788  	&& n >= o + 1
   789  	=> (ConstBool [false])
   790  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   791  	&& is8BitInt(t1)
   792  	&& isSamePtr(p1, p2)
   793  	&& n >= o + 1
   794  	=> (Const8 [0])
   795  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   796  	&& is16BitInt(t1)
   797  	&& isSamePtr(p1, p2)
   798  	&& n >= o + 2
   799  	=> (Const16 [0])
   800  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   801  	&& is32BitInt(t1)
   802  	&& isSamePtr(p1, p2)
   803  	&& n >= o + 4
   804  	=> (Const32 [0])
   805  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   806  	&& is64BitInt(t1)
   807  	&& isSamePtr(p1, p2)
   808  	&& n >= o + 8
   809  	=> (Const64 [0])
   810  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   811  	&& is32BitFloat(t1)
   812  	&& isSamePtr(p1, p2)
   813  	&& n >= o + 4
   814  	=> (Const32F [0])
   815  (Load <t1> (OffPtr [o] p1) (Zero [n] p2 _))
   816  	&& is64BitFloat(t1)
   817  	&& isSamePtr(p1, p2)
   818  	&& n >= o + 8
   819  	=> (Const64F [0])
   820  
   821  // Eliminate stores of values that have just been loaded from the same location.
   822  // We also handle the common case where there are some intermediate stores.
   823  (Store {t1} p1 (Load <t2> p2 mem) mem)
   824  	&& isSamePtr(p1, p2)
   825  	&& t2.Size() == t1.Size()
   826  	=> mem
   827  (Store {t1} p1 (Load <t2> p2 oldmem) mem:(Store {t3} p3 _ oldmem))
   828  	&& isSamePtr(p1, p2)
   829  	&& t2.Size() == t1.Size()
   830  	&& disjoint(p1, t1.Size(), p3, t3.Size())
   831  	=> mem
   832  (Store {t1} p1 (Load <t2> p2 oldmem) mem:(Store {t3} p3 _ (Store {t4} p4 _ oldmem)))
   833  	&& isSamePtr(p1, p2)
   834  	&& t2.Size() == t1.Size()
   835  	&& disjoint(p1, t1.Size(), p3, t3.Size())
   836  	&& disjoint(p1, t1.Size(), p4, t4.Size())
   837  	=> mem
   838  (Store {t1} p1 (Load <t2> p2 oldmem) mem:(Store {t3} p3 _ (Store {t4} p4 _ (Store {t5} p5 _ oldmem))))
   839  	&& isSamePtr(p1, p2)
   840  	&& t2.Size() == t1.Size()
   841  	&& disjoint(p1, t1.Size(), p3, t3.Size())
   842  	&& disjoint(p1, t1.Size(), p4, t4.Size())
   843  	&& disjoint(p1, t1.Size(), p5, t5.Size())
   844  	=> mem
   845  
   846  // Don't Store zeros to cleared variables.
   847  (Store {t} (OffPtr [o] p1) x mem:(Zero [n] p2 _))
   848  	&& isConstZero(x)
   849  	&& o >= 0 && t.Size() + o <= n && isSamePtr(p1, p2)
   850  	=> mem
   851  (Store {t1} op:(OffPtr [o1] p1) x mem:(Store {t2} p2 _ (Zero [n] p3 _)))
   852  	&& isConstZero(x)
   853  	&& o1 >= 0 && t1.Size() + o1 <= n && isSamePtr(p1, p3)
   854  	&& disjoint(op, t1.Size(), p2, t2.Size())
   855  	=> mem
   856  (Store {t1} op:(OffPtr [o1] p1) x mem:(Store {t2} p2 _ (Store {t3} p3 _ (Zero [n] p4 _))))
   857  	&& isConstZero(x)
   858  	&& o1 >= 0 && t1.Size() + o1 <= n && isSamePtr(p1, p4)
   859  	&& disjoint(op, t1.Size(), p2, t2.Size())
   860  	&& disjoint(op, t1.Size(), p3, t3.Size())
   861  	=> mem
   862  (Store {t1} op:(OffPtr [o1] p1) x mem:(Store {t2} p2 _ (Store {t3} p3 _ (Store {t4} p4 _ (Zero [n] p5 _)))))
   863  	&& isConstZero(x)
   864  	&& o1 >= 0 && t1.Size() + o1 <= n && isSamePtr(p1, p5)
   865  	&& disjoint(op, t1.Size(), p2, t2.Size())
   866  	&& disjoint(op, t1.Size(), p3, t3.Size())
   867  	&& disjoint(op, t1.Size(), p4, t4.Size())
   868  	=> mem
   869  
   870  // Collapse OffPtr
   871  (OffPtr (OffPtr p [y]) [x]) => (OffPtr p [x+y])
   872  (OffPtr p [0]) && v.Type.Compare(p.Type) == types.CMPeq => p
   873  
   874  // indexing operations
   875  // Note: bounds check has already been done
   876  (PtrIndex <t> ptr idx) && config.PtrSize == 4 && is32Bit(t.Elem().Size()) => (AddPtr ptr (Mul32 <typ.Int> idx (Const32 <typ.Int> [int32(t.Elem().Size())])))
   877  (PtrIndex <t> ptr idx) && config.PtrSize == 8 => (AddPtr ptr (Mul64 <typ.Int> idx (Const64 <typ.Int> [t.Elem().Size()])))
   878  
   879  // struct operations
   880  (StructSelect (StructMake1 x)) => x
   881  (StructSelect [0] (StructMake2 x _)) => x
   882  (StructSelect [1] (StructMake2 _ x)) => x
   883  (StructSelect [0] (StructMake3 x _ _)) => x
   884  (StructSelect [1] (StructMake3 _ x _)) => x
   885  (StructSelect [2] (StructMake3 _ _ x)) => x
   886  (StructSelect [0] (StructMake4 x _ _ _)) => x
   887  (StructSelect [1] (StructMake4 _ x _ _)) => x
   888  (StructSelect [2] (StructMake4 _ _ x _)) => x
   889  (StructSelect [3] (StructMake4 _ _ _ x)) => x
   890  
   891  (Load <t> _ _) && t.IsStruct() && t.NumFields() == 0 && CanSSA(t) =>
   892    (StructMake0)
   893  (Load <t> ptr mem) && t.IsStruct() && t.NumFields() == 1 && CanSSA(t) =>
   894    (StructMake1
   895      (Load <t.FieldType(0)> (OffPtr <t.FieldType(0).PtrTo()> [0] ptr) mem))
   896  (Load <t> ptr mem) && t.IsStruct() && t.NumFields() == 2 && CanSSA(t) =>
   897    (StructMake2
   898      (Load <t.FieldType(0)> (OffPtr <t.FieldType(0).PtrTo()> [0]             ptr) mem)
   899      (Load <t.FieldType(1)> (OffPtr <t.FieldType(1).PtrTo()> [t.FieldOff(1)] ptr) mem))
   900  (Load <t> ptr mem) && t.IsStruct() && t.NumFields() == 3 && CanSSA(t) =>
   901    (StructMake3
   902      (Load <t.FieldType(0)> (OffPtr <t.FieldType(0).PtrTo()> [0]             ptr) mem)
   903      (Load <t.FieldType(1)> (OffPtr <t.FieldType(1).PtrTo()> [t.FieldOff(1)] ptr) mem)
   904      (Load <t.FieldType(2)> (OffPtr <t.FieldType(2).PtrTo()> [t.FieldOff(2)] ptr) mem))
   905  (Load <t> ptr mem) && t.IsStruct() && t.NumFields() == 4 && CanSSA(t) =>
   906    (StructMake4
   907      (Load <t.FieldType(0)> (OffPtr <t.FieldType(0).PtrTo()> [0]             ptr) mem)
   908      (Load <t.FieldType(1)> (OffPtr <t.FieldType(1).PtrTo()> [t.FieldOff(1)] ptr) mem)
   909      (Load <t.FieldType(2)> (OffPtr <t.FieldType(2).PtrTo()> [t.FieldOff(2)] ptr) mem)
   910      (Load <t.FieldType(3)> (OffPtr <t.FieldType(3).PtrTo()> [t.FieldOff(3)] ptr) mem))
   911  
   912  (StructSelect [i] x:(Load <t> ptr mem)) && !CanSSA(t) =>
   913    @x.Block (Load <v.Type> (OffPtr <v.Type.PtrTo()> [t.FieldOff(int(i))] ptr) mem)
   914  
   915  (Store _ (StructMake0) mem) => mem
   916  (Store dst (StructMake1 <t> f0) mem) =>
   917    (Store {t.FieldType(0)} (OffPtr <t.FieldType(0).PtrTo()> [0] dst) f0 mem)
   918  (Store dst (StructMake2 <t> f0 f1) mem) =>
   919    (Store {t.FieldType(1)}
   920      (OffPtr <t.FieldType(1).PtrTo()> [t.FieldOff(1)] dst)
   921      f1
   922      (Store {t.FieldType(0)}
   923        (OffPtr <t.FieldType(0).PtrTo()> [0] dst)
   924          f0 mem))
   925  (Store dst (StructMake3 <t> f0 f1 f2) mem) =>
   926    (Store {t.FieldType(2)}
   927      (OffPtr <t.FieldType(2).PtrTo()> [t.FieldOff(2)] dst)
   928      f2
   929      (Store {t.FieldType(1)}
   930        (OffPtr <t.FieldType(1).PtrTo()> [t.FieldOff(1)] dst)
   931        f1
   932        (Store {t.FieldType(0)}
   933          (OffPtr <t.FieldType(0).PtrTo()> [0] dst)
   934            f0 mem)))
   935  (Store dst (StructMake4 <t> f0 f1 f2 f3) mem) =>
   936    (Store {t.FieldType(3)}
   937      (OffPtr <t.FieldType(3).PtrTo()> [t.FieldOff(3)] dst)
   938      f3
   939      (Store {t.FieldType(2)}
   940        (OffPtr <t.FieldType(2).PtrTo()> [t.FieldOff(2)] dst)
   941        f2
   942        (Store {t.FieldType(1)}
   943          (OffPtr <t.FieldType(1).PtrTo()> [t.FieldOff(1)] dst)
   944          f1
   945          (Store {t.FieldType(0)}
   946            (OffPtr <t.FieldType(0).PtrTo()> [0] dst)
   947              f0 mem))))
   948  
   949  // Putting struct{*byte} and similar into direct interfaces.
   950  (IMake _typ (StructMake1 val)) => (IMake _typ val)
   951  (StructSelect [0] (IData x)) => (IData x)
   952  
   953  // un-SSAable values use mem->mem copies
   954  (Store {t} dst (Load src mem) mem) && !CanSSA(t) =>
   955  	(Move {t} [t.Size()] dst src mem)
   956  (Store {t} dst (Load src mem) (VarDef {x} mem)) && !CanSSA(t) =>
   957  	(Move {t} [t.Size()] dst src (VarDef {x} mem))
   958  
   959  // array ops
   960  (ArraySelect (ArrayMake1 x)) => x
   961  
   962  (Load <t> _ _) && t.IsArray() && t.NumElem() == 0 =>
   963    (ArrayMake0)
   964  
   965  (Load <t> ptr mem) && t.IsArray() && t.NumElem() == 1 && CanSSA(t) =>
   966    (ArrayMake1 (Load <t.Elem()> ptr mem))
   967  
   968  (Store _ (ArrayMake0) mem) => mem
   969  (Store dst (ArrayMake1 e) mem) => (Store {e.Type} dst e mem)
   970  
   971  // Putting [1]*byte and similar into direct interfaces.
   972  (IMake _typ (ArrayMake1 val)) => (IMake _typ val)
   973  (ArraySelect [0] (IData x)) => (IData x)
   974  
   975  // string ops
   976  // Decomposing StringMake and lowering of StringPtr and StringLen
   977  // happens in a later pass, dec, so that these operations are available
   978  // to other passes for optimizations.
   979  (StringPtr (StringMake (Addr <t> {s} base) _)) => (Addr <t> {s} base)
   980  (StringLen (StringMake _ (Const64 <t> [c]))) => (Const64 <t> [c])
   981  (ConstString {str}) && config.PtrSize == 4 && str == "" =>
   982    (StringMake (ConstNil) (Const32 <typ.Int> [0]))
   983  (ConstString {str}) && config.PtrSize == 8 && str == "" =>
   984    (StringMake (ConstNil) (Const64 <typ.Int> [0]))
   985  (ConstString {str}) && config.PtrSize == 4 && str != "" =>
   986    (StringMake
   987      (Addr <typ.BytePtr> {fe.StringData(str)}
   988        (SB))
   989      (Const32 <typ.Int> [int32(len(str))]))
   990  (ConstString {str}) && config.PtrSize == 8 && str != "" =>
   991    (StringMake
   992      (Addr <typ.BytePtr> {fe.StringData(str)}
   993        (SB))
   994      (Const64 <typ.Int> [int64(len(str))]))
   995  
   996  // slice ops
   997  // Only a few slice rules are provided here.  See dec.rules for
   998  // a more comprehensive set.
   999  (SliceLen (SliceMake _ (Const64 <t> [c]) _)) => (Const64 <t> [c])
  1000  (SliceCap (SliceMake _ _ (Const64 <t> [c]))) => (Const64 <t> [c])
  1001  (SliceLen (SliceMake _ (Const32 <t> [c]) _)) => (Const32 <t> [c])
  1002  (SliceCap (SliceMake _ _ (Const32 <t> [c]))) => (Const32 <t> [c])
  1003  (SlicePtr (SliceMake (SlicePtr x) _ _)) => (SlicePtr x)
  1004  (SliceLen (SliceMake _ (SliceLen x) _)) => (SliceLen x)
  1005  (SliceCap (SliceMake _ _ (SliceCap x))) => (SliceCap x)
  1006  (SliceCap (SliceMake _ _ (SliceLen x))) => (SliceLen x)
  1007  (ConstSlice) && config.PtrSize == 4 =>
  1008    (SliceMake
  1009      (ConstNil <v.Type.Elem().PtrTo()>)
  1010      (Const32 <typ.Int> [0])
  1011      (Const32 <typ.Int> [0]))
  1012  (ConstSlice) && config.PtrSize == 8 =>
  1013    (SliceMake
  1014      (ConstNil <v.Type.Elem().PtrTo()>)
  1015      (Const64 <typ.Int> [0])
  1016      (Const64 <typ.Int> [0]))
  1017  
  1018  // interface ops
  1019  (ConstInterface) =>
  1020    (IMake
  1021      (ConstNil <typ.Uintptr>)
  1022      (ConstNil <typ.BytePtr>))
  1023  
  1024  (NilCheck ptr:(GetG mem) mem) => ptr
  1025  
  1026  (If (Not cond) yes no) => (If cond no yes)
  1027  (If (ConstBool [c]) yes no) && c => (First yes no)
  1028  (If (ConstBool [c]) yes no) && !c => (First no yes)
  1029  
  1030  (Phi <t> nx:(Not x) ny:(Not y)) && nx.Uses == 1 && ny.Uses == 1 => (Not (Phi <t> x y))
  1031  
  1032  // Get rid of Convert ops for pointer arithmetic on unsafe.Pointer.
  1033  (Convert (Add(64|32) (Convert ptr mem) off) mem) => (AddPtr ptr off)
  1034  (Convert (Convert ptr mem) mem) => ptr
  1035  
  1036  // strength reduction of divide by a constant.
  1037  // See ../magic.go for a detailed description of these algorithms.
  1038  
  1039  // Unsigned divide by power of 2.  Strength reduce to a shift.
  1040  (Div8u  n (Const8  [c])) && isPowerOfTwo8(c)  => (Rsh8Ux64  n (Const64 <typ.UInt64> [log8(c)]))
  1041  (Div16u n (Const16 [c])) && isPowerOfTwo16(c) => (Rsh16Ux64 n (Const64 <typ.UInt64> [log16(c)]))
  1042  (Div32u n (Const32 [c])) && isPowerOfTwo32(c) => (Rsh32Ux64 n (Const64 <typ.UInt64> [log32(c)]))
  1043  (Div64u n (Const64 [c])) && isPowerOfTwo64(c) => (Rsh64Ux64 n (Const64 <typ.UInt64> [log64(c)]))
  1044  (Div64u n (Const64 [-1<<63]))                 => (Rsh64Ux64 n (Const64 <typ.UInt64> [63]))
  1045  
  1046  // Signed non-negative divide by power of 2.
  1047  (Div8  n (Const8  [c])) && isNonNegative(n) && isPowerOfTwo8(c)  => (Rsh8Ux64  n (Const64 <typ.UInt64> [log8(c)]))
  1048  (Div16 n (Const16 [c])) && isNonNegative(n) && isPowerOfTwo16(c) => (Rsh16Ux64 n (Const64 <typ.UInt64> [log16(c)]))
  1049  (Div32 n (Const32 [c])) && isNonNegative(n) && isPowerOfTwo32(c) => (Rsh32Ux64 n (Const64 <typ.UInt64> [log32(c)]))
  1050  (Div64 n (Const64 [c])) && isNonNegative(n) && isPowerOfTwo64(c) => (Rsh64Ux64 n (Const64 <typ.UInt64> [log64(c)]))
  1051  (Div64 n (Const64 [-1<<63])) && isNonNegative(n)                 => (Const64 [0])
  1052  
  1053  // Unsigned divide, not a power of 2.  Strength reduce to a multiply.
  1054  // For 8-bit divides, we just do a direct 9-bit by 8-bit multiply.
  1055  (Div8u x (Const8 [c])) && umagicOK8(c) =>
  1056    (Trunc32to8
  1057      (Rsh32Ux64 <typ.UInt32>
  1058        (Mul32 <typ.UInt32>
  1059          (Const32 <typ.UInt32> [int32(1<<8+umagic8(c).m)])
  1060          (ZeroExt8to32 x))
  1061        (Const64 <typ.UInt64> [8+umagic8(c).s])))
  1062  
  1063  // For 16-bit divides on 64-bit machines, we do a direct 17-bit by 16-bit multiply.
  1064  (Div16u x (Const16 [c])) && umagicOK16(c) && config.RegSize == 8 =>
  1065    (Trunc64to16
  1066      (Rsh64Ux64 <typ.UInt64>
  1067        (Mul64 <typ.UInt64>
  1068          (Const64 <typ.UInt64> [int64(1<<16+umagic16(c).m)])
  1069          (ZeroExt16to64 x))
  1070        (Const64 <typ.UInt64> [16+umagic16(c).s])))
  1071  
  1072  // For 16-bit divides on 32-bit machines
  1073  (Div16u x (Const16 [c])) && umagicOK16(c) && config.RegSize == 4 && umagic16(c).m&1 == 0 =>
  1074    (Trunc32to16
  1075      (Rsh32Ux64 <typ.UInt32>
  1076        (Mul32 <typ.UInt32>
  1077          (Const32 <typ.UInt32> [int32(1<<15+umagic16(c).m/2)])
  1078          (ZeroExt16to32 x))
  1079        (Const64 <typ.UInt64> [16+umagic16(c).s-1])))
  1080  (Div16u x (Const16 [c])) && umagicOK16(c) && config.RegSize == 4 && c&1 == 0 =>
  1081    (Trunc32to16
  1082      (Rsh32Ux64 <typ.UInt32>
  1083        (Mul32 <typ.UInt32>
  1084          (Const32 <typ.UInt32> [int32(1<<15+(umagic16(c).m+1)/2)])
  1085          (Rsh32Ux64 <typ.UInt32> (ZeroExt16to32 x) (Const64 <typ.UInt64> [1])))
  1086        (Const64 <typ.UInt64> [16+umagic16(c).s-2])))
  1087  (Div16u x (Const16 [c])) && umagicOK16(c) && config.RegSize == 4 && config.useAvg =>
  1088    (Trunc32to16
  1089      (Rsh32Ux64 <typ.UInt32>
  1090        (Avg32u
  1091          (Lsh32x64 <typ.UInt32> (ZeroExt16to32 x) (Const64 <typ.UInt64> [16]))
  1092          (Mul32 <typ.UInt32>
  1093            (Const32 <typ.UInt32> [int32(umagic16(c).m)])
  1094            (ZeroExt16to32 x)))
  1095        (Const64 <typ.UInt64> [16+umagic16(c).s-1])))
  1096  
  1097  // For 32-bit divides on 32-bit machines
  1098  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 4 && umagic32(c).m&1 == 0 && config.useHmul =>
  1099    (Rsh32Ux64 <typ.UInt32>
  1100      (Hmul32u <typ.UInt32>
  1101        (Const32 <typ.UInt32> [int32(1<<31+umagic32(c).m/2)])
  1102        x)
  1103      (Const64 <typ.UInt64> [umagic32(c).s-1]))
  1104  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 4 && c&1 == 0 && config.useHmul =>
  1105    (Rsh32Ux64 <typ.UInt32>
  1106      (Hmul32u <typ.UInt32>
  1107        (Const32 <typ.UInt32> [int32(1<<31+(umagic32(c).m+1)/2)])
  1108        (Rsh32Ux64 <typ.UInt32> x (Const64 <typ.UInt64> [1])))
  1109      (Const64 <typ.UInt64> [umagic32(c).s-2]))
  1110  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 4 && config.useAvg && config.useHmul =>
  1111    (Rsh32Ux64 <typ.UInt32>
  1112      (Avg32u
  1113        x
  1114        (Hmul32u <typ.UInt32>
  1115          (Const32 <typ.UInt32> [int32(umagic32(c).m)])
  1116          x))
  1117      (Const64 <typ.UInt64> [umagic32(c).s-1]))
  1118  
  1119  // For 32-bit divides on 64-bit machines
  1120  // We'll use a regular (non-hi) multiply for this case.
  1121  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 8 && umagic32(c).m&1 == 0 =>
  1122    (Trunc64to32
  1123      (Rsh64Ux64 <typ.UInt64>
  1124        (Mul64 <typ.UInt64>
  1125          (Const64 <typ.UInt64> [int64(1<<31+umagic32(c).m/2)])
  1126          (ZeroExt32to64 x))
  1127        (Const64 <typ.UInt64> [32+umagic32(c).s-1])))
  1128  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 8 && c&1 == 0 =>
  1129    (Trunc64to32
  1130      (Rsh64Ux64 <typ.UInt64>
  1131        (Mul64 <typ.UInt64>
  1132          (Const64 <typ.UInt64> [int64(1<<31+(umagic32(c).m+1)/2)])
  1133          (Rsh64Ux64 <typ.UInt64> (ZeroExt32to64 x) (Const64 <typ.UInt64> [1])))
  1134        (Const64 <typ.UInt64> [32+umagic32(c).s-2])))
  1135  (Div32u x (Const32 [c])) && umagicOK32(c) && config.RegSize == 8 && config.useAvg =>
  1136    (Trunc64to32
  1137      (Rsh64Ux64 <typ.UInt64>
  1138        (Avg64u
  1139          (Lsh64x64 <typ.UInt64> (ZeroExt32to64 x) (Const64 <typ.UInt64> [32]))
  1140          (Mul64 <typ.UInt64>
  1141            (Const64 <typ.UInt32> [int64(umagic32(c).m)])
  1142            (ZeroExt32to64 x)))
  1143        (Const64 <typ.UInt64> [32+umagic32(c).s-1])))
  1144  
  1145  // For unsigned 64-bit divides on 32-bit machines,
  1146  // if the constant fits in 16 bits (so that the last term
  1147  // fits in 32 bits), convert to three 32-bit divides by a constant.
  1148  //
  1149  // If 1<<32 = Q * c + R
  1150  // and    x = hi << 32 + lo
  1151  //
  1152  // Then x = (hi/c*c + hi%c) << 32 + lo
  1153  //        = hi/c*c<<32 + hi%c<<32 + lo
  1154  //        = hi/c*c<<32 + (hi%c)*(Q*c+R) + lo/c*c + lo%c
  1155  //        = hi/c*c<<32 + (hi%c)*Q*c + lo/c*c + (hi%c*R+lo%c)
  1156  // and x / c = (hi/c)<<32 + (hi%c)*Q + lo/c + (hi%c*R+lo%c)/c
  1157  (Div64u x (Const64 [c])) && c > 0 && c <= 0xFFFF && umagicOK32(int32(c)) && config.RegSize == 4 && config.useHmul =>
  1158    (Add64
  1159      (Add64 <typ.UInt64>
  1160        (Add64 <typ.UInt64>
  1161          (Lsh64x64 <typ.UInt64>
  1162            (ZeroExt32to64
  1163              (Div32u <typ.UInt32>
  1164                (Trunc64to32 <typ.UInt32> (Rsh64Ux64 <typ.UInt64> x (Const64 <typ.UInt64> [32])))
  1165                (Const32 <typ.UInt32> [int32(c)])))
  1166            (Const64 <typ.UInt64> [32]))
  1167          (ZeroExt32to64 (Div32u <typ.UInt32> (Trunc64to32 <typ.UInt32> x) (Const32 <typ.UInt32> [int32(c)]))))
  1168        (Mul64 <typ.UInt64>
  1169          (ZeroExt32to64 <typ.UInt64>
  1170            (Mod32u <typ.UInt32>
  1171              (Trunc64to32 <typ.UInt32> (Rsh64Ux64 <typ.UInt64> x (Const64 <typ.UInt64> [32])))
  1172              (Const32 <typ.UInt32> [int32(c)])))
  1173          (Const64 <typ.UInt64> [int64((1<<32)/c)])))
  1174        (ZeroExt32to64
  1175          (Div32u <typ.UInt32>
  1176            (Add32 <typ.UInt32>
  1177              (Mod32u <typ.UInt32> (Trunc64to32 <typ.UInt32> x) (Const32 <typ.UInt32> [int32(c)]))
  1178              (Mul32 <typ.UInt32>
  1179                (Mod32u <typ.UInt32>
  1180                  (Trunc64to32 <typ.UInt32> (Rsh64Ux64 <typ.UInt64> x (Const64 <typ.UInt64> [32])))
  1181                  (Const32 <typ.UInt32> [int32(c)]))
  1182                (Const32 <typ.UInt32> [int32((1<<32)%c)])))
  1183            (Const32 <typ.UInt32> [int32(c)]))))
  1184  
  1185  // For 64-bit divides on 64-bit machines
  1186  // (64-bit divides on 32-bit machines are lowered to a runtime call by the walk pass.)
  1187  (Div64u x (Const64 [c])) && umagicOK64(c) && config.RegSize == 8 && umagic64(c).m&1 == 0 && config.useHmul =>
  1188    (Rsh64Ux64 <typ.UInt64>
  1189      (Hmul64u <typ.UInt64>
  1190        (Const64 <typ.UInt64> [int64(1<<63+umagic64(c).m/2)])
  1191        x)
  1192      (Const64 <typ.UInt64> [umagic64(c).s-1]))
  1193  (Div64u x (Const64 [c])) && umagicOK64(c) && config.RegSize == 8 && c&1 == 0 && config.useHmul =>
  1194    (Rsh64Ux64 <typ.UInt64>
  1195      (Hmul64u <typ.UInt64>
  1196        (Const64 <typ.UInt64> [int64(1<<63+(umagic64(c).m+1)/2)])
  1197        (Rsh64Ux64 <typ.UInt64> x (Const64 <typ.UInt64> [1])))
  1198      (Const64 <typ.UInt64> [umagic64(c).s-2]))
  1199  (Div64u x (Const64 [c])) && umagicOK64(c) && config.RegSize == 8 && config.useAvg && config.useHmul =>
  1200    (Rsh64Ux64 <typ.UInt64>
  1201      (Avg64u
  1202        x
  1203        (Hmul64u <typ.UInt64>
  1204          (Const64 <typ.UInt64> [int64(umagic64(c).m)])
  1205          x))
  1206      (Const64 <typ.UInt64> [umagic64(c).s-1]))
  1207  
  1208  // Signed divide by a negative constant.  Rewrite to divide by a positive constant.
  1209  (Div8  <t> n (Const8  [c])) && c < 0 && c != -1<<7  => (Neg8  (Div8  <t> n (Const8  <t> [-c])))
  1210  (Div16 <t> n (Const16 [c])) && c < 0 && c != -1<<15 => (Neg16 (Div16 <t> n (Const16 <t> [-c])))
  1211  (Div32 <t> n (Const32 [c])) && c < 0 && c != -1<<31 => (Neg32 (Div32 <t> n (Const32 <t> [-c])))
  1212  (Div64 <t> n (Const64 [c])) && c < 0 && c != -1<<63 => (Neg64 (Div64 <t> n (Const64 <t> [-c])))
  1213  
  1214  // Dividing by the most-negative number.  Result is always 0 except
  1215  // if the input is also the most-negative number.
  1216  // We can detect that using the sign bit of x & -x.
  1217  (Div8  <t> x (Const8  [-1<<7 ])) => (Rsh8Ux64  (And8  <t> x (Neg8  <t> x)) (Const64 <typ.UInt64> [7 ]))
  1218  (Div16 <t> x (Const16 [-1<<15])) => (Rsh16Ux64 (And16 <t> x (Neg16 <t> x)) (Const64 <typ.UInt64> [15]))
  1219  (Div32 <t> x (Const32 [-1<<31])) => (Rsh32Ux64 (And32 <t> x (Neg32 <t> x)) (Const64 <typ.UInt64> [31]))
  1220  (Div64 <t> x (Const64 [-1<<63])) => (Rsh64Ux64 (And64 <t> x (Neg64 <t> x)) (Const64 <typ.UInt64> [63]))
  1221  
  1222  // Signed divide by power of 2.
  1223  // n / c =       n >> log(c) if n >= 0
  1224  //       = (n+c-1) >> log(c) if n < 0
  1225  // We conditionally add c-1 by adding n>>63>>(64-log(c)) (first shift signed, second shift unsigned).
  1226  (Div8  <t> n (Const8  [c])) && isPowerOfTwo8(c) =>
  1227    (Rsh8x64
  1228      (Add8  <t> n (Rsh8Ux64  <t> (Rsh8x64  <t> n (Const64 <typ.UInt64> [ 7])) (Const64 <typ.UInt64> [int64( 8-log8(c))])))
  1229      (Const64 <typ.UInt64> [int64(log8(c))]))
  1230  (Div16 <t> n (Const16 [c])) && isPowerOfTwo16(c) =>
  1231    (Rsh16x64
  1232      (Add16 <t> n (Rsh16Ux64 <t> (Rsh16x64 <t> n (Const64 <typ.UInt64> [15])) (Const64 <typ.UInt64> [int64(16-log16(c))])))
  1233      (Const64 <typ.UInt64> [int64(log16(c))]))
  1234  (Div32 <t> n (Const32 [c])) && isPowerOfTwo32(c) =>
  1235    (Rsh32x64
  1236      (Add32 <t> n (Rsh32Ux64 <t> (Rsh32x64 <t> n (Const64 <typ.UInt64> [31])) (Const64 <typ.UInt64> [int64(32-log32(c))])))
  1237      (Const64 <typ.UInt64> [int64(log32(c))]))
  1238  (Div64 <t> n (Const64 [c])) && isPowerOfTwo64(c) =>
  1239    (Rsh64x64
  1240      (Add64 <t> n (Rsh64Ux64 <t> (Rsh64x64 <t> n (Const64 <typ.UInt64> [63])) (Const64 <typ.UInt64> [int64(64-log64(c))])))
  1241      (Const64 <typ.UInt64> [int64(log64(c))]))
  1242  
  1243  // Signed divide, not a power of 2.  Strength reduce to a multiply.
  1244  (Div8 <t> x (Const8 [c])) && smagicOK8(c) =>
  1245    (Sub8 <t>
  1246      (Rsh32x64 <t>
  1247        (Mul32 <typ.UInt32>
  1248          (Const32 <typ.UInt32> [int32(smagic8(c).m)])
  1249          (SignExt8to32 x))
  1250        (Const64 <typ.UInt64> [8+smagic8(c).s]))
  1251      (Rsh32x64 <t>
  1252        (SignExt8to32 x)
  1253        (Const64 <typ.UInt64> [31])))
  1254  (Div16 <t> x (Const16 [c])) && smagicOK16(c) =>
  1255    (Sub16 <t>
  1256      (Rsh32x64 <t>
  1257        (Mul32 <typ.UInt32>
  1258          (Const32 <typ.UInt32> [int32(smagic16(c).m)])
  1259          (SignExt16to32 x))
  1260        (Const64 <typ.UInt64> [16+smagic16(c).s]))
  1261      (Rsh32x64 <t>
  1262        (SignExt16to32 x)
  1263        (Const64 <typ.UInt64> [31])))
  1264  (Div32 <t> x (Const32 [c])) && smagicOK32(c) && config.RegSize == 8 =>
  1265    (Sub32 <t>
  1266      (Rsh64x64 <t>
  1267        (Mul64 <typ.UInt64>
  1268          (Const64 <typ.UInt64> [int64(smagic32(c).m)])
  1269          (SignExt32to64 x))
  1270        (Const64 <typ.UInt64> [32+smagic32(c).s]))
  1271      (Rsh64x64 <t>
  1272        (SignExt32to64 x)
  1273        (Const64 <typ.UInt64> [63])))
  1274  (Div32 <t> x (Const32 [c])) && smagicOK32(c) && config.RegSize == 4 && smagic32(c).m&1 == 0 && config.useHmul =>
  1275    (Sub32 <t>
  1276      (Rsh32x64 <t>
  1277        (Hmul32 <t>
  1278          (Const32 <typ.UInt32> [int32(smagic32(c).m/2)])
  1279          x)
  1280        (Const64 <typ.UInt64> [smagic32(c).s-1]))
  1281      (Rsh32x64 <t>
  1282        x
  1283        (Const64 <typ.UInt64> [31])))
  1284  (Div32 <t> x (Const32 [c])) && smagicOK32(c) && config.RegSize == 4 && smagic32(c).m&1 != 0 && config.useHmul =>
  1285    (Sub32 <t>
  1286      (Rsh32x64 <t>
  1287        (Add32 <t>
  1288          (Hmul32 <t>
  1289            (Const32 <typ.UInt32> [int32(smagic32(c).m)])
  1290            x)
  1291          x)
  1292        (Const64 <typ.UInt64> [smagic32(c).s]))
  1293      (Rsh32x64 <t>
  1294        x
  1295        (Const64 <typ.UInt64> [31])))
  1296  (Div64 <t> x (Const64 [c])) && smagicOK64(c) && smagic64(c).m&1 == 0 && config.useHmul =>
  1297    (Sub64 <t>
  1298      (Rsh64x64 <t>
  1299        (Hmul64 <t>
  1300          (Const64 <typ.UInt64> [int64(smagic64(c).m/2)])
  1301          x)
  1302        (Const64 <typ.UInt64> [smagic64(c).s-1]))
  1303      (Rsh64x64 <t>
  1304        x
  1305        (Const64 <typ.UInt64> [63])))
  1306  (Div64 <t> x (Const64 [c])) && smagicOK64(c) && smagic64(c).m&1 != 0 && config.useHmul =>
  1307    (Sub64 <t>
  1308      (Rsh64x64 <t>
  1309        (Add64 <t>
  1310          (Hmul64 <t>
  1311            (Const64 <typ.UInt64> [int64(smagic64(c).m)])
  1312            x)
  1313          x)
  1314        (Const64 <typ.UInt64> [smagic64(c).s]))
  1315      (Rsh64x64 <t>
  1316        x
  1317        (Const64 <typ.UInt64> [63])))
  1318  
  1319  // Unsigned mod by power of 2 constant.
  1320  (Mod8u  <t> n (Const8  [c])) && isPowerOfTwo8(c)  => (And8  n (Const8  <t> [c-1]))
  1321  (Mod16u <t> n (Const16 [c])) && isPowerOfTwo16(c) => (And16 n (Const16 <t> [c-1]))
  1322  (Mod32u <t> n (Const32 [c])) && isPowerOfTwo32(c) => (And32 n (Const32 <t> [c-1]))
  1323  (Mod64u <t> n (Const64 [c])) && isPowerOfTwo64(c) => (And64 n (Const64 <t> [c-1]))
  1324  (Mod64u <t> n (Const64 [-1<<63]))                 => (And64 n (Const64 <t> [1<<63-1]))
  1325  
  1326  // Signed non-negative mod by power of 2 constant.
  1327  (Mod8  <t> n (Const8  [c])) && isNonNegative(n) && isPowerOfTwo8(c)  => (And8  n (Const8  <t> [c-1]))
  1328  (Mod16 <t> n (Const16 [c])) && isNonNegative(n) && isPowerOfTwo16(c) => (And16 n (Const16 <t> [c-1]))
  1329  (Mod32 <t> n (Const32 [c])) && isNonNegative(n) && isPowerOfTwo32(c) => (And32 n (Const32 <t> [c-1]))
  1330  (Mod64 <t> n (Const64 [c])) && isNonNegative(n) && isPowerOfTwo64(c) => (And64 n (Const64 <t> [c-1]))
  1331  (Mod64 n (Const64 [-1<<63])) && isNonNegative(n)                   => n
  1332  
  1333  // Signed mod by negative constant.
  1334  (Mod8  <t> n (Const8  [c])) && c < 0 && c != -1<<7  => (Mod8  <t> n (Const8  <t> [-c]))
  1335  (Mod16 <t> n (Const16 [c])) && c < 0 && c != -1<<15 => (Mod16 <t> n (Const16 <t> [-c]))
  1336  (Mod32 <t> n (Const32 [c])) && c < 0 && c != -1<<31 => (Mod32 <t> n (Const32 <t> [-c]))
  1337  (Mod64 <t> n (Const64 [c])) && c < 0 && c != -1<<63 => (Mod64 <t> n (Const64 <t> [-c]))
  1338  
  1339  // All other mods by constants, do A%B = A-(A/B*B).
  1340  // This implements % with two * and a bunch of ancillary ops.
  1341  // One of the * is free if the user's code also computes A/B.
  1342  (Mod8   <t> x (Const8  [c])) && x.Op != OpConst8  && (c > 0 || c == -1<<7)
  1343    => (Sub8  x (Mul8  <t> (Div8   <t> x (Const8  <t> [c])) (Const8  <t> [c])))
  1344  (Mod16  <t> x (Const16 [c])) && x.Op != OpConst16 && (c > 0 || c == -1<<15)
  1345    => (Sub16 x (Mul16 <t> (Div16  <t> x (Const16 <t> [c])) (Const16 <t> [c])))
  1346  (Mod32  <t> x (Const32 [c])) && x.Op != OpConst32 && (c > 0 || c == -1<<31)
  1347    => (Sub32 x (Mul32 <t> (Div32  <t> x (Const32 <t> [c])) (Const32 <t> [c])))
  1348  (Mod64  <t> x (Const64 [c])) && x.Op != OpConst64 && (c > 0 || c == -1<<63)
  1349    => (Sub64 x (Mul64 <t> (Div64  <t> x (Const64 <t> [c])) (Const64 <t> [c])))
  1350  (Mod8u  <t> x (Const8  [c])) && x.Op != OpConst8  && c > 0 && umagicOK8( c)
  1351    => (Sub8  x (Mul8  <t> (Div8u  <t> x (Const8  <t> [c])) (Const8  <t> [c])))
  1352  (Mod16u <t> x (Const16 [c])) && x.Op != OpConst16 && c > 0 && umagicOK16(c)
  1353    => (Sub16 x (Mul16 <t> (Div16u <t> x (Const16 <t> [c])) (Const16 <t> [c])))
  1354  (Mod32u <t> x (Const32 [c])) && x.Op != OpConst32 && c > 0 && umagicOK32(c)
  1355    => (Sub32 x (Mul32 <t> (Div32u <t> x (Const32 <t> [c])) (Const32 <t> [c])))
  1356  (Mod64u <t> x (Const64 [c])) && x.Op != OpConst64 && c > 0 && umagicOK64(c)
  1357    => (Sub64 x (Mul64 <t> (Div64u <t> x (Const64 <t> [c])) (Const64 <t> [c])))
  1358  
  1359  // For architectures without rotates on less than 32-bits, promote these checks to 32-bit.
  1360  (Eq8 (Mod8u x (Const8  [c])) (Const8 [0])) && x.Op != OpConst8 && udivisibleOK8(c) && !hasSmallRotate(config) =>
  1361  	(Eq32 (Mod32u <typ.UInt32> (ZeroExt8to32 <typ.UInt32> x) (Const32 <typ.UInt32> [int32(uint8(c))])) (Const32 <typ.UInt32> [0]))
  1362  (Eq16 (Mod16u x (Const16  [c])) (Const16 [0])) && x.Op != OpConst16 && udivisibleOK16(c) && !hasSmallRotate(config) =>
  1363  	(Eq32 (Mod32u <typ.UInt32> (ZeroExt16to32 <typ.UInt32> x) (Const32 <typ.UInt32> [int32(uint16(c))])) (Const32 <typ.UInt32> [0]))
  1364  (Eq8 (Mod8 x (Const8  [c])) (Const8 [0])) && x.Op != OpConst8 && sdivisibleOK8(c) && !hasSmallRotate(config) =>
  1365  	(Eq32 (Mod32 <typ.Int32> (SignExt8to32 <typ.Int32> x) (Const32 <typ.Int32> [int32(c)])) (Const32 <typ.Int32> [0]))
  1366  (Eq16 (Mod16 x (Const16  [c])) (Const16 [0])) && x.Op != OpConst16 && sdivisibleOK16(c) && !hasSmallRotate(config) =>
  1367  	(Eq32 (Mod32 <typ.Int32> (SignExt16to32 <typ.Int32> x) (Const32 <typ.Int32> [int32(c)])) (Const32 <typ.Int32> [0]))
  1368  
  1369  // Divisibility checks x%c == 0 convert to multiply and rotate.
  1370  // Note, x%c == 0 is rewritten as x == c*(x/c) during the opt pass
  1371  // where (x/c) is performed using multiplication with magic constants.
  1372  // To rewrite x%c == 0 requires pattern matching the rewritten expression
  1373  // and checking that the division by the same constant wasn't already calculated.
  1374  // This check is made by counting uses of the magic constant multiplication.
  1375  // Note that if there were an intermediate opt pass, this rule could be applied
  1376  // directly on the Div op and magic division rewrites could be delayed to late opt.
  1377  
  1378  // Unsigned divisibility checks convert to multiply and rotate.
  1379  (Eq8 x (Mul8 (Const8 [c])
  1380    (Trunc32to8
  1381      (Rsh32Ux64
  1382        mul:(Mul32
  1383          (Const32 [m])
  1384          (ZeroExt8to32 x))
  1385        (Const64 [s])))
  1386  	)
  1387  )
  1388    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1389    && m == int32(1<<8+umagic8(c).m) && s == 8+umagic8(c).s
  1390    && x.Op != OpConst8 && udivisibleOK8(c)
  1391   => (Leq8U
  1392  			(RotateLeft8 <typ.UInt8>
  1393  				(Mul8 <typ.UInt8>
  1394  					(Const8 <typ.UInt8> [int8(udivisible8(c).m)])
  1395  					x)
  1396  				(Const8 <typ.UInt8> [int8(8-udivisible8(c).k)])
  1397  				)
  1398  			(Const8 <typ.UInt8> [int8(udivisible8(c).max)])
  1399  		)
  1400  
  1401  (Eq16 x (Mul16 (Const16 [c])
  1402    (Trunc64to16
  1403      (Rsh64Ux64
  1404        mul:(Mul64
  1405          (Const64 [m])
  1406          (ZeroExt16to64 x))
  1407        (Const64 [s])))
  1408  	)
  1409  )
  1410    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1411    && m == int64(1<<16+umagic16(c).m) && s == 16+umagic16(c).s
  1412    && x.Op != OpConst16 && udivisibleOK16(c)
  1413   => (Leq16U
  1414  			(RotateLeft16 <typ.UInt16>
  1415  				(Mul16 <typ.UInt16>
  1416  					(Const16 <typ.UInt16> [int16(udivisible16(c).m)])
  1417  					x)
  1418  				(Const16 <typ.UInt16> [int16(16-udivisible16(c).k)])
  1419  				)
  1420  			(Const16 <typ.UInt16> [int16(udivisible16(c).max)])
  1421  		)
  1422  
  1423  (Eq16 x (Mul16 (Const16 [c])
  1424    (Trunc32to16
  1425      (Rsh32Ux64
  1426        mul:(Mul32
  1427          (Const32 [m])
  1428          (ZeroExt16to32 x))
  1429        (Const64 [s])))
  1430  	)
  1431  )
  1432    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1433    && m == int32(1<<15+umagic16(c).m/2) && s == 16+umagic16(c).s-1
  1434    && x.Op != OpConst16 && udivisibleOK16(c)
  1435   => (Leq16U
  1436  			(RotateLeft16 <typ.UInt16>
  1437  				(Mul16 <typ.UInt16>
  1438  					(Const16 <typ.UInt16> [int16(udivisible16(c).m)])
  1439  					x)
  1440  				(Const16 <typ.UInt16> [int16(16-udivisible16(c).k)])
  1441  				)
  1442  			(Const16 <typ.UInt16> [int16(udivisible16(c).max)])
  1443  		)
  1444  
  1445  (Eq16 x (Mul16 (Const16 [c])
  1446    (Trunc32to16
  1447      (Rsh32Ux64
  1448        mul:(Mul32
  1449          (Const32 [m])
  1450          (Rsh32Ux64 (ZeroExt16to32 x) (Const64 [1])))
  1451        (Const64 [s])))
  1452  	)
  1453  )
  1454    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1455    && m == int32(1<<15+(umagic16(c).m+1)/2) && s == 16+umagic16(c).s-2
  1456    && x.Op != OpConst16 && udivisibleOK16(c)
  1457   => (Leq16U
  1458  			(RotateLeft16 <typ.UInt16>
  1459  				(Mul16 <typ.UInt16>
  1460  					(Const16 <typ.UInt16> [int16(udivisible16(c).m)])
  1461  					x)
  1462  				(Const16 <typ.UInt16> [int16(16-udivisible16(c).k)])
  1463  				)
  1464  			(Const16 <typ.UInt16> [int16(udivisible16(c).max)])
  1465  		)
  1466  
  1467  (Eq16 x (Mul16 (Const16 [c])
  1468    (Trunc32to16
  1469      (Rsh32Ux64
  1470        (Avg32u
  1471          (Lsh32x64 (ZeroExt16to32 x) (Const64 [16]))
  1472          mul:(Mul32
  1473            (Const32 [m])
  1474            (ZeroExt16to32 x)))
  1475        (Const64 [s])))
  1476  	)
  1477  )
  1478    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1479    && m == int32(umagic16(c).m) && s == 16+umagic16(c).s-1
  1480    && x.Op != OpConst16 && udivisibleOK16(c)
  1481   => (Leq16U
  1482  			(RotateLeft16 <typ.UInt16>
  1483  				(Mul16 <typ.UInt16>
  1484  					(Const16 <typ.UInt16> [int16(udivisible16(c).m)])
  1485  					x)
  1486  				(Const16 <typ.UInt16> [int16(16-udivisible16(c).k)])
  1487  				)
  1488  			(Const16 <typ.UInt16> [int16(udivisible16(c).max)])
  1489  		)
  1490  
  1491  (Eq32 x (Mul32 (Const32 [c])
  1492  	(Rsh32Ux64
  1493  		mul:(Hmul32u
  1494  			(Const32 [m])
  1495  			x)
  1496  		(Const64 [s]))
  1497  	)
  1498  )
  1499    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1500    && m == int32(1<<31+umagic32(c).m/2) && s == umagic32(c).s-1
  1501  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1502   => (Leq32U
  1503  			(RotateLeft32 <typ.UInt32>
  1504  				(Mul32 <typ.UInt32>
  1505  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1506  					x)
  1507  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1508  				)
  1509  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1510  		)
  1511  
  1512  (Eq32 x (Mul32 (Const32 [c])
  1513    (Rsh32Ux64
  1514      mul:(Hmul32u
  1515        (Const32 <typ.UInt32> [m])
  1516        (Rsh32Ux64 x (Const64 [1])))
  1517      (Const64 [s]))
  1518  	)
  1519  )
  1520    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1521    && m == int32(1<<31+(umagic32(c).m+1)/2) && s == umagic32(c).s-2
  1522  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1523   => (Leq32U
  1524  			(RotateLeft32 <typ.UInt32>
  1525  				(Mul32 <typ.UInt32>
  1526  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1527  					x)
  1528  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1529  				)
  1530  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1531  		)
  1532  
  1533  (Eq32 x (Mul32 (Const32 [c])
  1534    (Rsh32Ux64
  1535      (Avg32u
  1536        x
  1537        mul:(Hmul32u
  1538          (Const32 [m])
  1539          x))
  1540      (Const64 [s]))
  1541  	)
  1542  )
  1543    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1544    && m == int32(umagic32(c).m) && s == umagic32(c).s-1
  1545  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1546   => (Leq32U
  1547  			(RotateLeft32 <typ.UInt32>
  1548  				(Mul32 <typ.UInt32>
  1549  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1550  					x)
  1551  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1552  				)
  1553  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1554  		)
  1555  
  1556  (Eq32 x (Mul32 (Const32 [c])
  1557    (Trunc64to32
  1558      (Rsh64Ux64
  1559        mul:(Mul64
  1560          (Const64 [m])
  1561          (ZeroExt32to64 x))
  1562        (Const64 [s])))
  1563  	)
  1564  )
  1565    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1566    && m == int64(1<<31+umagic32(c).m/2) && s == 32+umagic32(c).s-1
  1567  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1568   => (Leq32U
  1569  			(RotateLeft32 <typ.UInt32>
  1570  				(Mul32 <typ.UInt32>
  1571  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1572  					x)
  1573  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1574  				)
  1575  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1576  		)
  1577  
  1578  (Eq32 x (Mul32 (Const32 [c])
  1579    (Trunc64to32
  1580      (Rsh64Ux64
  1581        mul:(Mul64
  1582          (Const64 [m])
  1583          (Rsh64Ux64 (ZeroExt32to64 x) (Const64 [1])))
  1584        (Const64 [s])))
  1585  	)
  1586  )
  1587    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1588    && m == int64(1<<31+(umagic32(c).m+1)/2) && s == 32+umagic32(c).s-2
  1589  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1590   => (Leq32U
  1591  			(RotateLeft32 <typ.UInt32>
  1592  				(Mul32 <typ.UInt32>
  1593  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1594  					x)
  1595  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1596  				)
  1597  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1598  		)
  1599  
  1600  (Eq32 x (Mul32 (Const32 [c])
  1601    (Trunc64to32
  1602      (Rsh64Ux64
  1603        (Avg64u
  1604          (Lsh64x64 (ZeroExt32to64 x) (Const64 [32]))
  1605          mul:(Mul64
  1606            (Const64 [m])
  1607            (ZeroExt32to64 x)))
  1608        (Const64 [s])))
  1609  	)
  1610  )
  1611    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1612    && m == int64(umagic32(c).m) && s == 32+umagic32(c).s-1
  1613  	&& x.Op != OpConst32 && udivisibleOK32(c)
  1614   => (Leq32U
  1615  			(RotateLeft32 <typ.UInt32>
  1616  				(Mul32 <typ.UInt32>
  1617  					(Const32 <typ.UInt32> [int32(udivisible32(c).m)])
  1618  					x)
  1619  				(Const32 <typ.UInt32> [int32(32-udivisible32(c).k)])
  1620  				)
  1621  			(Const32 <typ.UInt32> [int32(udivisible32(c).max)])
  1622  		)
  1623  
  1624  (Eq64 x (Mul64 (Const64 [c])
  1625  	(Rsh64Ux64
  1626  		mul:(Hmul64u
  1627  			(Const64 [m])
  1628  			x)
  1629  		(Const64 [s]))
  1630  	)
  1631  ) && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1632    && m == int64(1<<63+umagic64(c).m/2) && s == umagic64(c).s-1
  1633    && x.Op != OpConst64 && udivisibleOK64(c)
  1634   => (Leq64U
  1635  			(RotateLeft64 <typ.UInt64>
  1636  				(Mul64 <typ.UInt64>
  1637  					(Const64 <typ.UInt64> [int64(udivisible64(c).m)])
  1638  					x)
  1639  				(Const64 <typ.UInt64> [64-udivisible64(c).k])
  1640  				)
  1641  			(Const64 <typ.UInt64> [int64(udivisible64(c).max)])
  1642  		)
  1643  (Eq64 x (Mul64 (Const64 [c])
  1644  	(Rsh64Ux64
  1645  		mul:(Hmul64u
  1646  			(Const64 [m])
  1647  			(Rsh64Ux64 x (Const64 [1])))
  1648  		(Const64 [s]))
  1649  	)
  1650  ) && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1651    && m == int64(1<<63+(umagic64(c).m+1)/2) && s == umagic64(c).s-2
  1652    && x.Op != OpConst64 && udivisibleOK64(c)
  1653   => (Leq64U
  1654  			(RotateLeft64 <typ.UInt64>
  1655  				(Mul64 <typ.UInt64>
  1656  					(Const64 <typ.UInt64> [int64(udivisible64(c).m)])
  1657  					x)
  1658  				(Const64 <typ.UInt64> [64-udivisible64(c).k])
  1659  				)
  1660  			(Const64 <typ.UInt64> [int64(udivisible64(c).max)])
  1661  		)
  1662  (Eq64 x (Mul64 (Const64 [c])
  1663  	(Rsh64Ux64
  1664  		(Avg64u
  1665  			x
  1666  			mul:(Hmul64u
  1667  				(Const64 [m])
  1668  				x))
  1669  		(Const64 [s]))
  1670  	)
  1671  ) && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1672    && m == int64(umagic64(c).m) && s == umagic64(c).s-1
  1673    && x.Op != OpConst64 && udivisibleOK64(c)
  1674   => (Leq64U
  1675  			(RotateLeft64 <typ.UInt64>
  1676  				(Mul64 <typ.UInt64>
  1677  					(Const64 <typ.UInt64> [int64(udivisible64(c).m)])
  1678  					x)
  1679  				(Const64 <typ.UInt64> [64-udivisible64(c).k])
  1680  				)
  1681  			(Const64 <typ.UInt64> [int64(udivisible64(c).max)])
  1682  		)
  1683  
  1684  // Signed divisibility checks convert to multiply, add and rotate.
  1685  (Eq8 x (Mul8 (Const8 [c])
  1686    (Sub8
  1687      (Rsh32x64
  1688        mul:(Mul32
  1689          (Const32 [m])
  1690          (SignExt8to32 x))
  1691        (Const64 [s]))
  1692      (Rsh32x64
  1693        (SignExt8to32 x)
  1694        (Const64 [31])))
  1695  	)
  1696  )
  1697    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1698    && m == int32(smagic8(c).m) && s == 8+smagic8(c).s
  1699  	&& x.Op != OpConst8 && sdivisibleOK8(c)
  1700   => (Leq8U
  1701  			(RotateLeft8 <typ.UInt8>
  1702  				(Add8 <typ.UInt8>
  1703  					(Mul8 <typ.UInt8>
  1704  						(Const8 <typ.UInt8> [int8(sdivisible8(c).m)])
  1705  						x)
  1706  					(Const8 <typ.UInt8> [int8(sdivisible8(c).a)])
  1707  				)
  1708  				(Const8 <typ.UInt8> [int8(8-sdivisible8(c).k)])
  1709  			)
  1710  			(Const8 <typ.UInt8> [int8(sdivisible8(c).max)])
  1711  		)
  1712  
  1713  (Eq16 x (Mul16 (Const16 [c])
  1714    (Sub16
  1715      (Rsh32x64
  1716        mul:(Mul32
  1717          (Const32 [m])
  1718          (SignExt16to32 x))
  1719        (Const64 [s]))
  1720      (Rsh32x64
  1721        (SignExt16to32 x)
  1722        (Const64 [31])))
  1723  	)
  1724  )
  1725    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1726    && m == int32(smagic16(c).m) && s == 16+smagic16(c).s
  1727  	&& x.Op != OpConst16 && sdivisibleOK16(c)
  1728   => (Leq16U
  1729  			(RotateLeft16 <typ.UInt16>
  1730  				(Add16 <typ.UInt16>
  1731  					(Mul16 <typ.UInt16>
  1732  						(Const16 <typ.UInt16> [int16(sdivisible16(c).m)])
  1733  						x)
  1734  					(Const16 <typ.UInt16> [int16(sdivisible16(c).a)])
  1735  				)
  1736  				(Const16 <typ.UInt16> [int16(16-sdivisible16(c).k)])
  1737  			)
  1738  			(Const16 <typ.UInt16> [int16(sdivisible16(c).max)])
  1739  		)
  1740  
  1741  (Eq32 x (Mul32 (Const32 [c])
  1742    (Sub32
  1743      (Rsh64x64
  1744        mul:(Mul64
  1745          (Const64 [m])
  1746          (SignExt32to64 x))
  1747        (Const64 [s]))
  1748      (Rsh64x64
  1749        (SignExt32to64 x)
  1750        (Const64 [63])))
  1751  	)
  1752  )
  1753    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1754    && m == int64(smagic32(c).m) && s == 32+smagic32(c).s
  1755  	&& x.Op != OpConst32 && sdivisibleOK32(c)
  1756   => (Leq32U
  1757  			(RotateLeft32 <typ.UInt32>
  1758  				(Add32 <typ.UInt32>
  1759  					(Mul32 <typ.UInt32>
  1760  						(Const32 <typ.UInt32> [int32(sdivisible32(c).m)])
  1761  						x)
  1762  					(Const32 <typ.UInt32> [int32(sdivisible32(c).a)])
  1763  				)
  1764  				(Const32 <typ.UInt32> [int32(32-sdivisible32(c).k)])
  1765  			)
  1766  			(Const32 <typ.UInt32> [int32(sdivisible32(c).max)])
  1767  		)
  1768  
  1769  (Eq32 x (Mul32 (Const32 [c])
  1770    (Sub32
  1771      (Rsh32x64
  1772        mul:(Hmul32
  1773          (Const32 [m])
  1774          x)
  1775        (Const64 [s]))
  1776      (Rsh32x64
  1777        x
  1778        (Const64 [31])))
  1779  	)
  1780  )
  1781    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1782    && m == int32(smagic32(c).m/2) && s == smagic32(c).s-1
  1783  	&& x.Op != OpConst32 && sdivisibleOK32(c)
  1784   => (Leq32U
  1785  			(RotateLeft32 <typ.UInt32>
  1786  				(Add32 <typ.UInt32>
  1787  					(Mul32 <typ.UInt32>
  1788  						(Const32 <typ.UInt32> [int32(sdivisible32(c).m)])
  1789  						x)
  1790  					(Const32 <typ.UInt32> [int32(sdivisible32(c).a)])
  1791  				)
  1792  				(Const32 <typ.UInt32> [int32(32-sdivisible32(c).k)])
  1793  			)
  1794  			(Const32 <typ.UInt32> [int32(sdivisible32(c).max)])
  1795  		)
  1796  
  1797  (Eq32 x (Mul32 (Const32 [c])
  1798    (Sub32
  1799      (Rsh32x64
  1800        (Add32
  1801          mul:(Hmul32
  1802            (Const32 [m])
  1803            x)
  1804          x)
  1805        (Const64 [s]))
  1806      (Rsh32x64
  1807        x
  1808        (Const64 [31])))
  1809  	)
  1810  )
  1811    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1812    && m == int32(smagic32(c).m) && s == smagic32(c).s
  1813  	&& x.Op != OpConst32 && sdivisibleOK32(c)
  1814   => (Leq32U
  1815  			(RotateLeft32 <typ.UInt32>
  1816  				(Add32 <typ.UInt32>
  1817  					(Mul32 <typ.UInt32>
  1818  						(Const32 <typ.UInt32> [int32(sdivisible32(c).m)])
  1819  						x)
  1820  					(Const32 <typ.UInt32> [int32(sdivisible32(c).a)])
  1821  				)
  1822  				(Const32 <typ.UInt32> [int32(32-sdivisible32(c).k)])
  1823  			)
  1824  			(Const32 <typ.UInt32> [int32(sdivisible32(c).max)])
  1825  		)
  1826  
  1827  (Eq64 x (Mul64 (Const64 [c])
  1828    (Sub64
  1829      (Rsh64x64
  1830        mul:(Hmul64
  1831          (Const64 [m])
  1832          x)
  1833        (Const64 [s]))
  1834      (Rsh64x64
  1835        x
  1836        (Const64 [63])))
  1837  	)
  1838  )
  1839    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1840    && m == int64(smagic64(c).m/2) && s == smagic64(c).s-1
  1841  	&& x.Op != OpConst64 && sdivisibleOK64(c)
  1842   => (Leq64U
  1843  			(RotateLeft64 <typ.UInt64>
  1844  				(Add64 <typ.UInt64>
  1845  					(Mul64 <typ.UInt64>
  1846  						(Const64 <typ.UInt64> [int64(sdivisible64(c).m)])
  1847  						x)
  1848  					(Const64 <typ.UInt64> [int64(sdivisible64(c).a)])
  1849  				)
  1850  				(Const64 <typ.UInt64> [64-sdivisible64(c).k])
  1851  			)
  1852  			(Const64 <typ.UInt64> [int64(sdivisible64(c).max)])
  1853  		)
  1854  
  1855  (Eq64 x (Mul64 (Const64 [c])
  1856    (Sub64
  1857      (Rsh64x64
  1858        (Add64
  1859          mul:(Hmul64
  1860            (Const64 [m])
  1861            x)
  1862          x)
  1863        (Const64 [s]))
  1864      (Rsh64x64
  1865        x
  1866        (Const64 [63])))
  1867  	)
  1868  )
  1869    && v.Block.Func.pass.name != "opt" && mul.Uses == 1
  1870    && m == int64(smagic64(c).m) && s == smagic64(c).s
  1871  	&& x.Op != OpConst64 && sdivisibleOK64(c)
  1872   => (Leq64U
  1873  			(RotateLeft64 <typ.UInt64>
  1874  				(Add64 <typ.UInt64>
  1875  					(Mul64 <typ.UInt64>
  1876  						(Const64 <typ.UInt64> [int64(sdivisible64(c).m)])
  1877  						x)
  1878  					(Const64 <typ.UInt64> [int64(sdivisible64(c).a)])
  1879  				)
  1880  				(Const64 <typ.UInt64> [64-sdivisible64(c).k])
  1881  			)
  1882  			(Const64 <typ.UInt64> [int64(sdivisible64(c).max)])
  1883  		)
  1884  
  1885  // Divisibility check for signed integers for power of two constant are simple mask.
  1886  // However, we must match against the rewritten n%c == 0 -> n - c*(n/c) == 0 -> n == c*(n/c)
  1887  // where n/c contains fixup code to handle signed n.
  1888  ((Eq8|Neq8) n (Lsh8x64
  1889    (Rsh8x64
  1890      (Add8  <t> n (Rsh8Ux64  <t> (Rsh8x64  <t> n (Const64 <typ.UInt64> [ 7])) (Const64 <typ.UInt64> [kbar])))
  1891      (Const64 <typ.UInt64> [k]))
  1892  	(Const64 <typ.UInt64> [k]))
  1893  ) && k > 0 && k < 7 && kbar == 8 - k
  1894    => ((Eq8|Neq8) (And8 <t> n (Const8 <t> [1<<uint(k)-1])) (Const8 <t> [0]))
  1895  
  1896  ((Eq16|Neq16) n (Lsh16x64
  1897    (Rsh16x64
  1898      (Add16 <t> n (Rsh16Ux64 <t> (Rsh16x64 <t> n (Const64 <typ.UInt64> [15])) (Const64 <typ.UInt64> [kbar])))
  1899      (Const64 <typ.UInt64> [k]))
  1900  	(Const64 <typ.UInt64> [k]))
  1901  ) && k > 0 && k < 15 && kbar == 16 - k
  1902    => ((Eq16|Neq16) (And16 <t> n (Const16 <t> [1<<uint(k)-1])) (Const16 <t> [0]))
  1903  
  1904  ((Eq32|Neq32) n (Lsh32x64
  1905    (Rsh32x64
  1906      (Add32 <t> n (Rsh32Ux64 <t> (Rsh32x64 <t> n (Const64 <typ.UInt64> [31])) (Const64 <typ.UInt64> [kbar])))
  1907      (Const64 <typ.UInt64> [k]))
  1908  	(Const64 <typ.UInt64> [k]))
  1909  ) && k > 0 && k < 31 && kbar == 32 - k
  1910    => ((Eq32|Neq32) (And32 <t> n (Const32 <t> [1<<uint(k)-1])) (Const32 <t> [0]))
  1911  
  1912  ((Eq64|Neq64) n (Lsh64x64
  1913    (Rsh64x64
  1914      (Add64 <t> n (Rsh64Ux64 <t> (Rsh64x64 <t> n (Const64 <typ.UInt64> [63])) (Const64 <typ.UInt64> [kbar])))
  1915      (Const64 <typ.UInt64> [k]))
  1916  	(Const64 <typ.UInt64> [k]))
  1917  ) && k > 0 && k < 63 && kbar == 64 - k
  1918    => ((Eq64|Neq64) (And64 <t> n (Const64 <t> [1<<uint(k)-1])) (Const64 <t> [0]))
  1919  
  1920  (Eq(8|16|32|64)  s:(Sub(8|16|32|64) x y) (Const(8|16|32|64) [0])) && s.Uses == 1 => (Eq(8|16|32|64)  x y)
  1921  (Neq(8|16|32|64) s:(Sub(8|16|32|64) x y) (Const(8|16|32|64) [0])) && s.Uses == 1 => (Neq(8|16|32|64) x y)
  1922  
  1923  // Optimize bitsets
  1924  (Eq8 (And8 <t> x (Const8 <t> [y])) (Const8 <t> [y])) && oneBit8(y)
  1925    => (Neq8 (And8 <t> x (Const8 <t> [y])) (Const8 <t> [0]))
  1926  (Eq16 (And16 <t> x (Const16 <t> [y])) (Const16 <t> [y])) && oneBit16(y)
  1927    => (Neq16 (And16 <t> x (Const16 <t> [y])) (Const16 <t> [0]))
  1928  (Eq32 (And32 <t> x (Const32 <t> [y])) (Const32 <t> [y])) && oneBit32(y)
  1929    => (Neq32 (And32 <t> x (Const32 <t> [y])) (Const32 <t> [0]))
  1930  (Eq64 (And64 <t> x (Const64 <t> [y])) (Const64 <t> [y])) && oneBit64(y)
  1931    => (Neq64 (And64 <t> x (Const64 <t> [y])) (Const64 <t> [0]))
  1932  (Neq8 (And8 <t> x (Const8 <t> [y])) (Const8 <t> [y])) && oneBit8(y)
  1933    => (Eq8 (And8 <t> x (Const8 <t> [y])) (Const8 <t> [0]))
  1934  (Neq16 (And16 <t> x (Const16 <t> [y])) (Const16 <t> [y])) && oneBit16(y)
  1935    => (Eq16 (And16 <t> x (Const16 <t> [y])) (Const16 <t> [0]))
  1936  (Neq32 (And32 <t> x (Const32 <t> [y])) (Const32 <t> [y])) && oneBit32(y)
  1937    => (Eq32 (And32 <t> x (Const32 <t> [y])) (Const32 <t> [0]))
  1938  (Neq64 (And64 <t> x (Const64 <t> [y])) (Const64 <t> [y])) && oneBit64(y)
  1939    => (Eq64 (And64 <t> x (Const64 <t> [y])) (Const64 <t> [0]))
  1940  
  1941  // Reassociate expressions involving
  1942  // constants such that constants come first,
  1943  // exposing obvious constant-folding opportunities.
  1944  // Reassociate (op (op y C) x) to (op C (op x y)) or similar, where C
  1945  // is constant, which pushes constants to the outside
  1946  // of the expression. At that point, any constant-folding
  1947  // opportunities should be obvious.
  1948  // Note: don't include AddPtr here! In order to maintain the
  1949  // invariant that pointers must stay within the pointed-to object,
  1950  // we can't pull part of a pointer computation above the AddPtr.
  1951  // See issue 37881.
  1952  // Note: we don't need to handle any (x-C) cases because we already rewrite
  1953  // (x-C) to (x+(-C)).
  1954  
  1955  // x + (C + z) -> C + (x + z)
  1956  (Add64 (Add64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Add64 i (Add64 <t> z x))
  1957  (Add32 (Add32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Add32 i (Add32 <t> z x))
  1958  (Add16 (Add16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Add16 i (Add16 <t> z x))
  1959  (Add8  (Add8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Add8  i (Add8  <t> z x))
  1960  
  1961  // x + (C - z) -> C + (x - z)
  1962  (Add64 (Sub64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Add64 i (Sub64 <t> x z))
  1963  (Add32 (Sub32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Add32 i (Sub32 <t> x z))
  1964  (Add16 (Sub16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Add16 i (Sub16 <t> x z))
  1965  (Add8  (Sub8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Add8  i (Sub8  <t> x z))
  1966  
  1967  // x - (C - z) -> x + (z - C) -> (x + z) - C
  1968  (Sub64 x (Sub64 i:(Const64 <t>) z)) && (z.Op != OpConst64 && x.Op != OpConst64) => (Sub64 (Add64 <t> x z) i)
  1969  (Sub32 x (Sub32 i:(Const32 <t>) z)) && (z.Op != OpConst32 && x.Op != OpConst32) => (Sub32 (Add32 <t> x z) i)
  1970  (Sub16 x (Sub16 i:(Const16 <t>) z)) && (z.Op != OpConst16 && x.Op != OpConst16) => (Sub16 (Add16 <t> x z) i)
  1971  (Sub8  x (Sub8  i:(Const8  <t>) z)) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Sub8  (Add8  <t> x z) i)
  1972  
  1973  // x - (z + C) -> x + (-z - C) -> (x - z) - C
  1974  (Sub64 x (Add64 z i:(Const64 <t>))) && (z.Op != OpConst64 && x.Op != OpConst64) => (Sub64 (Sub64 <t> x z) i)
  1975  (Sub32 x (Add32 z i:(Const32 <t>))) && (z.Op != OpConst32 && x.Op != OpConst32) => (Sub32 (Sub32 <t> x z) i)
  1976  (Sub16 x (Add16 z i:(Const16 <t>))) && (z.Op != OpConst16 && x.Op != OpConst16) => (Sub16 (Sub16 <t> x z) i)
  1977  (Sub8  x (Add8  z i:(Const8  <t>))) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Sub8 (Sub8  <t> x z) i)
  1978  
  1979  // (C - z) - x -> C - (z + x)
  1980  (Sub64 (Sub64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Sub64 i (Add64 <t> z x))
  1981  (Sub32 (Sub32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Sub32 i (Add32 <t> z x))
  1982  (Sub16 (Sub16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Sub16 i (Add16 <t> z x))
  1983  (Sub8  (Sub8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Sub8  i (Add8  <t> z x))
  1984  
  1985  // (z + C) -x -> C + (z - x)
  1986  (Sub64 (Add64 z i:(Const64 <t>)) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Add64 i (Sub64 <t> z x))
  1987  (Sub32 (Add32 z i:(Const32 <t>)) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Add32 i (Sub32 <t> z x))
  1988  (Sub16 (Add16 z i:(Const16 <t>)) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Add16 i (Sub16 <t> z x))
  1989  (Sub8  (Add8  z i:(Const8  <t>)) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Add8  i (Sub8  <t> z x))
  1990  
  1991  // x & (C & z) -> C & (x & z)
  1992  (And64 (And64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (And64 i (And64 <t> z x))
  1993  (And32 (And32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (And32 i (And32 <t> z x))
  1994  (And16 (And16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (And16 i (And16 <t> z x))
  1995  (And8  (And8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (And8  i (And8  <t> z x))
  1996  
  1997  // x | (C | z) -> C | (x | z)
  1998  (Or64 (Or64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Or64 i (Or64 <t> z x))
  1999  (Or32 (Or32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Or32 i (Or32 <t> z x))
  2000  (Or16 (Or16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Or16 i (Or16 <t> z x))
  2001  (Or8  (Or8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Or8  i (Or8  <t> z x))
  2002  
  2003  // x ^ (C ^ z) -> C ^ (x ^ z)
  2004  (Xor64 (Xor64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Xor64 i (Xor64 <t> z x))
  2005  (Xor32 (Xor32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Xor32 i (Xor32 <t> z x))
  2006  (Xor16 (Xor16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Xor16 i (Xor16 <t> z x))
  2007  (Xor8  (Xor8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Xor8  i (Xor8  <t> z x))
  2008  
  2009  // x * (D * z) = D * (x * z)
  2010  (Mul64 (Mul64 i:(Const64 <t>) z) x) && (z.Op != OpConst64 && x.Op != OpConst64) => (Mul64 i (Mul64 <t> x z))
  2011  (Mul32 (Mul32 i:(Const32 <t>) z) x) && (z.Op != OpConst32 && x.Op != OpConst32) => (Mul32 i (Mul32 <t> x z))
  2012  (Mul16 (Mul16 i:(Const16 <t>) z) x) && (z.Op != OpConst16 && x.Op != OpConst16) => (Mul16 i (Mul16 <t> x z))
  2013  (Mul8  (Mul8  i:(Const8  <t>) z) x) && (z.Op != OpConst8  && x.Op != OpConst8)  => (Mul8  i (Mul8  <t> x z))
  2014  
  2015  // C + (D + x) -> (C + D) + x
  2016  (Add64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Add64 (Const64 <t> [c+d]) x)
  2017  (Add32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Add32 (Const32 <t> [c+d]) x)
  2018  (Add16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) => (Add16 (Const16 <t> [c+d]) x)
  2019  (Add8  (Const8  <t> [c]) (Add8  (Const8  <t> [d]) x)) => (Add8  (Const8  <t> [c+d]) x)
  2020  
  2021  // C + (D - x) -> (C + D) - x
  2022  (Add64 (Const64 <t> [c]) (Sub64 (Const64 <t> [d]) x)) => (Sub64 (Const64 <t> [c+d]) x)
  2023  (Add32 (Const32 <t> [c]) (Sub32 (Const32 <t> [d]) x)) => (Sub32 (Const32 <t> [c+d]) x)
  2024  (Add16 (Const16 <t> [c]) (Sub16 (Const16 <t> [d]) x)) => (Sub16 (Const16 <t> [c+d]) x)
  2025  (Add8  (Const8  <t> [c]) (Sub8  (Const8  <t> [d]) x)) => (Sub8  (Const8  <t> [c+d]) x)
  2026  
  2027  // C - (D - x) -> (C - D) + x
  2028  (Sub64 (Const64 <t> [c]) (Sub64 (Const64 <t> [d]) x)) => (Add64 (Const64 <t> [c-d]) x)
  2029  (Sub32 (Const32 <t> [c]) (Sub32 (Const32 <t> [d]) x)) => (Add32 (Const32 <t> [c-d]) x)
  2030  (Sub16 (Const16 <t> [c]) (Sub16 (Const16 <t> [d]) x)) => (Add16 (Const16 <t> [c-d]) x)
  2031  (Sub8  (Const8  <t> [c]) (Sub8  (Const8  <t> [d]) x)) => (Add8  (Const8  <t> [c-d]) x)
  2032  
  2033  // C - (D + x) -> (C - D) - x
  2034  (Sub64 (Const64 <t> [c]) (Add64 (Const64 <t> [d]) x)) => (Sub64 (Const64 <t> [c-d]) x)
  2035  (Sub32 (Const32 <t> [c]) (Add32 (Const32 <t> [d]) x)) => (Sub32 (Const32 <t> [c-d]) x)
  2036  (Sub16 (Const16 <t> [c]) (Add16 (Const16 <t> [d]) x)) => (Sub16 (Const16 <t> [c-d]) x)
  2037  (Sub8  (Const8  <t> [c]) (Add8  (Const8  <t> [d]) x)) => (Sub8  (Const8  <t> [c-d]) x)
  2038  
  2039  // C & (D & x) -> (C & D) & x
  2040  (And64 (Const64 <t> [c]) (And64 (Const64 <t> [d]) x)) => (And64 (Const64 <t> [c&d]) x)
  2041  (And32 (Const32 <t> [c]) (And32 (Const32 <t> [d]) x)) => (And32 (Const32 <t> [c&d]) x)
  2042  (And16 (Const16 <t> [c]) (And16 (Const16 <t> [d]) x)) => (And16 (Const16 <t> [c&d]) x)
  2043  (And8  (Const8  <t> [c]) (And8  (Const8  <t> [d]) x)) => (And8  (Const8  <t> [c&d]) x)
  2044  
  2045  // C | (D | x) -> (C | D) | x
  2046  (Or64 (Const64 <t> [c]) (Or64 (Const64 <t> [d]) x)) => (Or64 (Const64 <t> [c|d]) x)
  2047  (Or32 (Const32 <t> [c]) (Or32 (Const32 <t> [d]) x)) => (Or32 (Const32 <t> [c|d]) x)
  2048  (Or16 (Const16 <t> [c]) (Or16 (Const16 <t> [d]) x)) => (Or16 (Const16 <t> [c|d]) x)
  2049  (Or8  (Const8  <t> [c]) (Or8  (Const8  <t> [d]) x)) => (Or8  (Const8  <t> [c|d]) x)
  2050  
  2051  // C ^ (D ^ x) -> (C ^ D) ^ x
  2052  (Xor64 (Const64 <t> [c]) (Xor64 (Const64 <t> [d]) x)) => (Xor64 (Const64 <t> [c^d]) x)
  2053  (Xor32 (Const32 <t> [c]) (Xor32 (Const32 <t> [d]) x)) => (Xor32 (Const32 <t> [c^d]) x)
  2054  (Xor16 (Const16 <t> [c]) (Xor16 (Const16 <t> [d]) x)) => (Xor16 (Const16 <t> [c^d]) x)
  2055  (Xor8  (Const8  <t> [c]) (Xor8  (Const8  <t> [d]) x)) => (Xor8  (Const8  <t> [c^d]) x)
  2056  
  2057  // C * (D * x) = (C * D) * x
  2058  (Mul64 (Const64 <t> [c]) (Mul64 (Const64 <t> [d]) x)) => (Mul64 (Const64 <t> [c*d]) x)
  2059  (Mul32 (Const32 <t> [c]) (Mul32 (Const32 <t> [d]) x)) => (Mul32 (Const32 <t> [c*d]) x)
  2060  (Mul16 (Const16 <t> [c]) (Mul16 (Const16 <t> [d]) x)) => (Mul16 (Const16 <t> [c*d]) x)
  2061  (Mul8  (Const8  <t> [c]) (Mul8  (Const8  <t> [d]) x)) => (Mul8  (Const8  <t> [c*d]) x)
  2062  
  2063  // floating point optimizations
  2064  (Mul(32|64)F x (Const(32|64)F [1])) => x
  2065  (Mul32F x (Const32F [-1])) => (Neg32F x)
  2066  (Mul64F x (Const64F [-1])) => (Neg64F x)
  2067  (Mul32F x (Const32F [2])) => (Add32F x x)
  2068  (Mul64F x (Const64F [2])) => (Add64F x x)
  2069  
  2070  (Div32F x (Const32F <t> [c])) && reciprocalExact32(c) => (Mul32F x (Const32F <t> [1/c]))
  2071  (Div64F x (Const64F <t> [c])) && reciprocalExact64(c) => (Mul64F x (Const64F <t> [1/c]))
  2072  
  2073  // rewrite single-precision sqrt expression "float32(math.Sqrt(float64(x)))"
  2074  (Cvt64Fto32F sqrt0:(Sqrt (Cvt32Fto64F x))) && sqrt0.Uses==1 => (Sqrt32 x)
  2075  
  2076  (Sqrt (Const64F [c])) && !math.IsNaN(math.Sqrt(c)) => (Const64F [math.Sqrt(c)])
  2077  
  2078  // for rewriting results of some late-expanded rewrites (below)
  2079  (SelectN [0] (MakeResult x ___)) => x
  2080  (SelectN [1] (MakeResult x y ___)) => y
  2081  (SelectN [2] (MakeResult x y z ___)) => z
  2082  
  2083  // for late-expanded calls, recognize newobject and remove zeroing and nilchecks
  2084  (Zero (SelectN [0] call:(StaticLECall _ _)) mem:(SelectN [1] call))
  2085  	&& isSameCall(call.Aux, "runtime.newobject")
  2086  	=> mem
  2087  
  2088  (Store (SelectN [0] call:(StaticLECall _ _)) x mem:(SelectN [1] call))
  2089  	&& isConstZero(x)
  2090  	&& isSameCall(call.Aux, "runtime.newobject")
  2091  	=> mem
  2092  
  2093  (Store (OffPtr (SelectN [0] call:(StaticLECall _ _))) x mem:(SelectN [1] call))
  2094  	&& isConstZero(x)
  2095  	&& isSameCall(call.Aux, "runtime.newobject")
  2096  	=> mem
  2097  
  2098  (NilCheck ptr:(SelectN [0] call:(StaticLECall _ _)) _)
  2099  	&& isSameCall(call.Aux, "runtime.newobject")
  2100  	&& warnRule(fe.Debug_checknil(), v, "removed nil check")
  2101  	=> ptr
  2102  
  2103  (NilCheck ptr:(OffPtr (SelectN [0] call:(StaticLECall _ _))) _)
  2104  	&& isSameCall(call.Aux, "runtime.newobject")
  2105  	&& warnRule(fe.Debug_checknil(), v, "removed nil check")
  2106  	=> ptr
  2107  
  2108  // Addresses of globals are always non-nil.
  2109  (NilCheck          ptr:(Addr {_} (SB))    _) => ptr
  2110  (NilCheck ptr:(Convert (Addr {_} (SB)) _) _) => ptr
  2111  
  2112  // for late-expanded calls, recognize memequal applied to a single constant byte
  2113  // Support is limited by 1, 2, 4, 8 byte sizes
  2114  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [1]) mem)
  2115    && isSameCall(callAux, "runtime.memequal")
  2116    && symIsRO(scon)
  2117    => (MakeResult (Eq8 (Load <typ.Int8> sptr mem) (Const8 <typ.Int8> [int8(read8(scon,0))])) mem)
  2118  
  2119  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [1]) mem)
  2120    && isSameCall(callAux, "runtime.memequal")
  2121    && symIsRO(scon)
  2122    => (MakeResult (Eq8 (Load <typ.Int8> sptr mem) (Const8 <typ.Int8> [int8(read8(scon,0))])) mem)
  2123  
  2124  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [2]) mem)
  2125    && isSameCall(callAux, "runtime.memequal")
  2126    && symIsRO(scon)
  2127    && canLoadUnaligned(config)
  2128    => (MakeResult (Eq16 (Load <typ.Int16> sptr mem) (Const16 <typ.Int16> [int16(read16(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2129  
  2130  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [2]) mem)
  2131    && isSameCall(callAux, "runtime.memequal")
  2132    && symIsRO(scon)
  2133    && canLoadUnaligned(config)
  2134    => (MakeResult (Eq16 (Load <typ.Int16> sptr mem) (Const16 <typ.Int16> [int16(read16(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2135  
  2136  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [4]) mem)
  2137    && isSameCall(callAux, "runtime.memequal")
  2138    && symIsRO(scon)
  2139    && canLoadUnaligned(config)
  2140    => (MakeResult (Eq32 (Load <typ.Int32> sptr mem) (Const32 <typ.Int32> [int32(read32(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2141  
  2142  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [4]) mem)
  2143    && isSameCall(callAux, "runtime.memequal")
  2144    && symIsRO(scon)
  2145    && canLoadUnaligned(config)
  2146    => (MakeResult (Eq32 (Load <typ.Int32> sptr mem) (Const32 <typ.Int32> [int32(read32(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2147  
  2148  (StaticLECall {callAux} sptr (Addr {scon} (SB)) (Const64 [8]) mem)
  2149    && isSameCall(callAux, "runtime.memequal")
  2150    && symIsRO(scon)
  2151    && canLoadUnaligned(config) && config.PtrSize == 8
  2152    => (MakeResult (Eq64 (Load <typ.Int64> sptr mem) (Const64 <typ.Int64> [int64(read64(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2153  
  2154  (StaticLECall {callAux} (Addr {scon} (SB)) sptr (Const64 [8]) mem)
  2155    && isSameCall(callAux, "runtime.memequal")
  2156    && symIsRO(scon)
  2157    && canLoadUnaligned(config) && config.PtrSize == 8
  2158    => (MakeResult (Eq64 (Load <typ.Int64> sptr mem) (Const64 <typ.Int64> [int64(read64(scon,0,config.ctxt.Arch.ByteOrder))])) mem)
  2159  
  2160  (StaticLECall {callAux} _ _ (Const64 [0]) mem)
  2161    && isSameCall(callAux, "runtime.memequal")
  2162    => (MakeResult (ConstBool <typ.Bool> [true]) mem)
  2163  
  2164  (Static(Call|LECall) {callAux} p q _ mem)
  2165    && isSameCall(callAux, "runtime.memequal")
  2166    && isSamePtr(p, q)
  2167    => (MakeResult (ConstBool <typ.Bool> [true]) mem)
  2168  
  2169  // Turn known-size calls to memclrNoHeapPointers into a Zero.
  2170  // Note that we are using types.Types[types.TUINT8] instead of sptr.Type.Elem() - see issue 55122 and CL 431496 for more details.
  2171  (SelectN [0] call:(StaticCall {sym} sptr (Const(64|32) [c]) mem))
  2172    && isInlinableMemclr(config, int64(c))
  2173    && isSameCall(sym, "runtime.memclrNoHeapPointers")
  2174    && call.Uses == 1
  2175    && clobber(call)
  2176    => (Zero {types.Types[types.TUINT8]} [int64(c)] sptr mem)
  2177  
  2178  // Recognise make([]T, 0) and replace it with a pointer to the zerobase
  2179  (StaticLECall {callAux} _ (Const(64|32) [0]) (Const(64|32) [0]) mem)
  2180  	&& isSameCall(callAux, "runtime.makeslice")
  2181  	=> (MakeResult (Addr <v.Type.FieldType(0)> {ir.Syms.Zerobase} (SB)) mem)
  2182  
  2183  // Evaluate constant address comparisons.
  2184  (EqPtr  x x) => (ConstBool [true])
  2185  (NeqPtr x x) => (ConstBool [false])
  2186  (EqPtr  (Addr {x} _) (Addr {y} _)) => (ConstBool [x == y])
  2187  (EqPtr  (Addr {x} _) (OffPtr [o] (Addr {y} _))) => (ConstBool [x == y && o == 0])
  2188  (EqPtr  (OffPtr [o1] (Addr {x} _)) (OffPtr [o2] (Addr {y} _))) => (ConstBool [x == y && o1 == o2])
  2189  (NeqPtr (Addr {x} _) (Addr {y} _)) => (ConstBool [x != y])
  2190  (NeqPtr (Addr {x} _) (OffPtr [o] (Addr {y} _))) => (ConstBool [x != y || o != 0])
  2191  (NeqPtr (OffPtr [o1] (Addr {x} _)) (OffPtr [o2] (Addr {y} _))) => (ConstBool [x != y || o1 != o2])
  2192  (EqPtr  (LocalAddr {x} _ _) (LocalAddr {y} _ _)) => (ConstBool [x == y])
  2193  (EqPtr  (LocalAddr {x} _ _) (OffPtr [o] (LocalAddr {y} _ _))) => (ConstBool [x == y && o == 0])
  2194  (EqPtr  (OffPtr [o1] (LocalAddr {x} _ _)) (OffPtr [o2] (LocalAddr {y} _ _))) => (ConstBool [x == y && o1 == o2])
  2195  (NeqPtr (LocalAddr {x} _ _) (LocalAddr {y} _ _)) => (ConstBool [x != y])
  2196  (NeqPtr (LocalAddr {x} _ _) (OffPtr [o] (LocalAddr {y} _ _))) => (ConstBool [x != y || o != 0])
  2197  (NeqPtr (OffPtr [o1] (LocalAddr {x} _ _)) (OffPtr [o2] (LocalAddr {y} _ _))) => (ConstBool [x != y || o1 != o2])
  2198  (EqPtr  (OffPtr [o1] p1) p2) && isSamePtr(p1, p2) => (ConstBool [o1 == 0])
  2199  (NeqPtr (OffPtr [o1] p1) p2) && isSamePtr(p1, p2) => (ConstBool [o1 != 0])
  2200  (EqPtr  (OffPtr [o1] p1) (OffPtr [o2] p2)) && isSamePtr(p1, p2) => (ConstBool [o1 == o2])
  2201  (NeqPtr (OffPtr [o1] p1) (OffPtr [o2] p2)) && isSamePtr(p1, p2) => (ConstBool [o1 != o2])
  2202  (EqPtr  (Const(32|64) [c]) (Const(32|64) [d])) => (ConstBool [c == d])
  2203  (NeqPtr (Const(32|64) [c]) (Const(32|64) [d])) => (ConstBool [c != d])
  2204  (EqPtr  (Convert (Addr {x} _) _) (Addr {y} _)) => (ConstBool [x==y])
  2205  (NeqPtr (Convert (Addr {x} _) _) (Addr {y} _)) => (ConstBool [x!=y])
  2206  
  2207  (EqPtr  (LocalAddr _ _) (Addr _)) => (ConstBool [false])
  2208  (EqPtr  (OffPtr (LocalAddr _ _)) (Addr _)) => (ConstBool [false])
  2209  (EqPtr  (LocalAddr _ _) (OffPtr (Addr _))) => (ConstBool [false])
  2210  (EqPtr  (OffPtr (LocalAddr _ _)) (OffPtr (Addr _))) => (ConstBool [false])
  2211  (NeqPtr (LocalAddr _ _) (Addr _)) => (ConstBool [true])
  2212  (NeqPtr (OffPtr (LocalAddr _ _)) (Addr _)) => (ConstBool [true])
  2213  (NeqPtr (LocalAddr _ _) (OffPtr (Addr _))) => (ConstBool [true])
  2214  (NeqPtr (OffPtr (LocalAddr _ _)) (OffPtr (Addr _))) => (ConstBool [true])
  2215  
  2216  // Simplify address comparisons.
  2217  (EqPtr  (AddPtr p1 o1) p2) && isSamePtr(p1, p2) => (Not (IsNonNil o1))
  2218  (NeqPtr (AddPtr p1 o1) p2) && isSamePtr(p1, p2) => (IsNonNil o1)
  2219  (EqPtr  (Const(32|64) [0]) p) => (Not (IsNonNil p))
  2220  (NeqPtr (Const(32|64) [0]) p) => (IsNonNil p)
  2221  (EqPtr  (ConstNil) p) => (Not (IsNonNil p))
  2222  (NeqPtr (ConstNil) p) => (IsNonNil p)
  2223  
  2224  // Evaluate constant user nil checks.
  2225  (IsNonNil (ConstNil)) => (ConstBool [false])
  2226  (IsNonNil (Const(32|64) [c])) => (ConstBool [c != 0])
  2227  (IsNonNil          (Addr _)   ) => (ConstBool [true])
  2228  (IsNonNil (Convert (Addr _) _)) => (ConstBool [true])
  2229  (IsNonNil (LocalAddr _ _)) => (ConstBool [true])
  2230  
  2231  // Inline small or disjoint runtime.memmove calls with constant length.
  2232  // See the comment in op Move in genericOps.go for discussion of the type.
  2233  //
  2234  // Note that we've lost any knowledge of the type and alignment requirements
  2235  // of the source and destination. We only know the size, and that the type
  2236  // contains no pointers.
  2237  // The type of the move is not necessarily v.Args[0].Type().Elem()!
  2238  // See issue 55122 for details.
  2239  //
  2240  // Because expand calls runs after prove, constants useful to this pattern may not appear.
  2241  // Both versions need to exist; the memory and register variants.
  2242  //
  2243  // Match post-expansion calls, memory version.
  2244  (SelectN [0] call:(StaticCall {sym} s1:(Store _ (Const(64|32) [sz]) s2:(Store  _ src s3:(Store {t} _ dst mem)))))
  2245  	&& sz >= 0
  2246  	&& isSameCall(sym, "runtime.memmove")
  2247  	&& s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1
  2248  	&& isInlinableMemmove(dst, src, int64(sz), config)
  2249  	&& clobber(s1, s2, s3, call)
  2250  	=> (Move {types.Types[types.TUINT8]} [int64(sz)] dst src mem)
  2251  
  2252  // Match post-expansion calls, register version.
  2253  (SelectN [0] call:(StaticCall {sym} dst src (Const(64|32) [sz]) mem))
  2254  	&& sz >= 0
  2255  	&& call.Uses == 1 // this will exclude all calls with results
  2256  	&& isSameCall(sym, "runtime.memmove")
  2257  	&& isInlinableMemmove(dst, src, int64(sz), config)
  2258  	&& clobber(call)
  2259  	=> (Move {types.Types[types.TUINT8]} [int64(sz)] dst src mem)
  2260  
  2261  // Match pre-expansion calls.
  2262  (SelectN [0] call:(StaticLECall {sym} dst src (Const(64|32) [sz]) mem))
  2263  	&& sz >= 0
  2264  	&& call.Uses == 1 // this will exclude all calls with results
  2265  	&& isSameCall(sym, "runtime.memmove")
  2266  	&& isInlinableMemmove(dst, src, int64(sz), config)
  2267  	&& clobber(call)
  2268  	=> (Move {types.Types[types.TUINT8]} [int64(sz)] dst src mem)
  2269  
  2270  // De-virtualize late-expanded interface calls into late-expanded static calls.
  2271  (InterLECall [argsize] {auxCall} (Addr {fn} (SB)) ___) => devirtLECall(v, fn.(*obj.LSym))
  2272  
  2273  // Move and Zero optimizations.
  2274  // Move source and destination may overlap.
  2275  
  2276  // Convert Moves into Zeros when the source is known to be zeros.
  2277  (Move {t} [n] dst1 src mem:(Zero {t} [n] dst2 _)) && isSamePtr(src, dst2)
  2278  	=> (Zero {t} [n] dst1 mem)
  2279  (Move {t} [n] dst1 src mem:(VarDef (Zero {t} [n] dst0 _))) && isSamePtr(src, dst0)
  2280  	=> (Zero {t} [n] dst1 mem)
  2281  (Move {t} [n] dst (Addr {sym} (SB)) mem) && symIsROZero(sym) => (Zero {t} [n] dst mem)
  2282  
  2283  // Don't Store to variables that are about to be overwritten by Move/Zero.
  2284  (Zero {t1} [n] p1 store:(Store {t2} (OffPtr [o2] p2) _ mem))
  2285  	&& isSamePtr(p1, p2) && store.Uses == 1
  2286  	&& n >= o2 + t2.Size()
  2287  	&& clobber(store)
  2288  	=> (Zero {t1} [n] p1 mem)
  2289  (Move {t1} [n] dst1 src1 store:(Store {t2} op:(OffPtr [o2] dst2) _ mem))
  2290  	&& isSamePtr(dst1, dst2) && store.Uses == 1
  2291  	&& n >= o2 + t2.Size()
  2292  	&& disjoint(src1, n, op, t2.Size())
  2293  	&& clobber(store)
  2294  	=> (Move {t1} [n] dst1 src1 mem)
  2295  
  2296  // Don't Move to variables that are immediately completely overwritten.
  2297  (Zero {t} [n] dst1 move:(Move {t} [n] dst2 _ mem))
  2298  	&& move.Uses == 1
  2299  	&& isSamePtr(dst1, dst2)
  2300  	&& clobber(move)
  2301  	=> (Zero {t} [n] dst1 mem)
  2302  (Move {t} [n] dst1 src1 move:(Move {t} [n] dst2 _ mem))
  2303  	&& move.Uses == 1
  2304  	&& isSamePtr(dst1, dst2) && disjoint(src1, n, dst2, n)
  2305  	&& clobber(move)
  2306  	=> (Move {t} [n] dst1 src1 mem)
  2307  (Zero {t} [n] dst1 vardef:(VarDef {x} move:(Move {t} [n] dst2 _ mem)))
  2308  	&& move.Uses == 1 && vardef.Uses == 1
  2309  	&& isSamePtr(dst1, dst2)
  2310  	&& clobber(move, vardef)
  2311  	=> (Zero {t} [n] dst1 (VarDef {x} mem))
  2312  (Move {t} [n] dst1 src1 vardef:(VarDef {x} move:(Move {t} [n] dst2 _ mem)))
  2313  	&& move.Uses == 1 && vardef.Uses == 1
  2314  	&& isSamePtr(dst1, dst2) && disjoint(src1, n, dst2, n)
  2315  	&& clobber(move, vardef)
  2316  	=> (Move {t} [n] dst1 src1 (VarDef {x} mem))
  2317  (Store {t1} op1:(OffPtr [o1] p1) d1
  2318  	m2:(Store {t2} op2:(OffPtr [0] p2) d2
  2319  		m3:(Move [n] p3 _ mem)))
  2320  	&& m2.Uses == 1 && m3.Uses == 1
  2321  	&& o1 == t2.Size()
  2322  	&& n == t2.Size() + t1.Size()
  2323  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2324  	&& clobber(m2, m3)
  2325  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 mem))
  2326  (Store {t1} op1:(OffPtr [o1] p1) d1
  2327  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  2328  		m3:(Store {t3} op3:(OffPtr [0] p3) d3
  2329  			m4:(Move [n] p4 _ mem))))
  2330  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1
  2331  	&& o2 == t3.Size()
  2332  	&& o1-o2 == t2.Size()
  2333  	&& n == t3.Size() + t2.Size() + t1.Size()
  2334  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2335  	&& clobber(m2, m3, m4)
  2336  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 mem)))
  2337  (Store {t1} op1:(OffPtr [o1] p1) d1
  2338  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  2339  		m3:(Store {t3} op3:(OffPtr [o3] p3) d3
  2340  			m4:(Store {t4} op4:(OffPtr [0] p4) d4
  2341  				m5:(Move [n] p5 _ mem)))))
  2342  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1 && m5.Uses == 1
  2343  	&& o3 == t4.Size()
  2344  	&& o2-o3 == t3.Size()
  2345  	&& o1-o2 == t2.Size()
  2346  	&& n == t4.Size() + t3.Size() + t2.Size() + t1.Size()
  2347  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2348  	&& clobber(m2, m3, m4, m5)
  2349  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 (Store {t4} op4 d4 mem))))
  2350  
  2351  // Don't Zero variables that are immediately completely overwritten
  2352  // before being accessed.
  2353  (Move {t} [n] dst1 src1 zero:(Zero {t} [n] dst2 mem))
  2354  	&& zero.Uses == 1
  2355  	&& isSamePtr(dst1, dst2) && disjoint(src1, n, dst2, n)
  2356  	&& clobber(zero)
  2357  	=> (Move {t} [n] dst1 src1 mem)
  2358  (Move {t} [n] dst1 src1 vardef:(VarDef {x} zero:(Zero {t} [n] dst2 mem)))
  2359  	&& zero.Uses == 1 && vardef.Uses == 1
  2360  	&& isSamePtr(dst1, dst2) && disjoint(src1, n, dst2, n)
  2361  	&& clobber(zero, vardef)
  2362  	=> (Move {t} [n] dst1 src1 (VarDef {x} mem))
  2363  (Store {t1} op1:(OffPtr [o1] p1) d1
  2364  	m2:(Store {t2} op2:(OffPtr [0] p2) d2
  2365  		m3:(Zero [n] p3 mem)))
  2366  	&& m2.Uses == 1 && m3.Uses == 1
  2367  	&& o1 == t2.Size()
  2368  	&& n == t2.Size() + t1.Size()
  2369  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2370  	&& clobber(m2, m3)
  2371  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 mem))
  2372  (Store {t1} op1:(OffPtr [o1] p1) d1
  2373  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  2374  		m3:(Store {t3} op3:(OffPtr [0] p3) d3
  2375  			m4:(Zero [n] p4 mem))))
  2376  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1
  2377  	&& o2 == t3.Size()
  2378  	&& o1-o2 == t2.Size()
  2379  	&& n == t3.Size() + t2.Size() + t1.Size()
  2380  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2381  	&& clobber(m2, m3, m4)
  2382  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 mem)))
  2383  (Store {t1} op1:(OffPtr [o1] p1) d1
  2384  	m2:(Store {t2} op2:(OffPtr [o2] p2) d2
  2385  		m3:(Store {t3} op3:(OffPtr [o3] p3) d3
  2386  			m4:(Store {t4} op4:(OffPtr [0] p4) d4
  2387  				m5:(Zero [n] p5 mem)))))
  2388  	&& m2.Uses == 1 && m3.Uses == 1 && m4.Uses == 1 && m5.Uses == 1
  2389  	&& o3 == t4.Size()
  2390  	&& o2-o3 == t3.Size()
  2391  	&& o1-o2 == t2.Size()
  2392  	&& n == t4.Size() + t3.Size() + t2.Size() + t1.Size()
  2393  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2394  	&& clobber(m2, m3, m4, m5)
  2395  	=> (Store {t1} op1 d1 (Store {t2} op2 d2 (Store {t3} op3 d3 (Store {t4} op4 d4 mem))))
  2396  
  2397  // Don't Move from memory if the values are likely to already be
  2398  // in registers.
  2399  (Move {t1} [n] dst p1
  2400  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2401  		(Store {t3} op3:(OffPtr <tt3> [0] p3) d2 _)))
  2402  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2403  	&& t2.Alignment() <= t1.Alignment()
  2404  	&& t3.Alignment() <= t1.Alignment()
  2405  	&& registerizable(b, t2)
  2406  	&& registerizable(b, t3)
  2407  	&& o2 == t3.Size()
  2408  	&& n == t2.Size() + t3.Size()
  2409  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2410  		(Store {t3} (OffPtr <tt3> [0] dst) d2 mem))
  2411  (Move {t1} [n] dst p1
  2412  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2413  		(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  2414  			(Store {t4} op4:(OffPtr <tt4> [0] p4) d3 _))))
  2415  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2416  	&& t2.Alignment() <= t1.Alignment()
  2417  	&& t3.Alignment() <= t1.Alignment()
  2418  	&& t4.Alignment() <= t1.Alignment()
  2419  	&& registerizable(b, t2)
  2420  	&& registerizable(b, t3)
  2421  	&& registerizable(b, t4)
  2422  	&& o3 == t4.Size()
  2423  	&& o2-o3 == t3.Size()
  2424  	&& n == t2.Size() + t3.Size() + t4.Size()
  2425  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2426  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2427  			(Store {t4} (OffPtr <tt4> [0] dst) d3 mem)))
  2428  (Move {t1} [n] dst p1
  2429  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2430  		(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  2431  			(Store {t4} op4:(OffPtr <tt4> [o4] p4) d3
  2432  				(Store {t5} op5:(OffPtr <tt5> [0] p5) d4 _)))))
  2433  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2434  	&& t2.Alignment() <= t1.Alignment()
  2435  	&& t3.Alignment() <= t1.Alignment()
  2436  	&& t4.Alignment() <= t1.Alignment()
  2437  	&& t5.Alignment() <= t1.Alignment()
  2438  	&& registerizable(b, t2)
  2439  	&& registerizable(b, t3)
  2440  	&& registerizable(b, t4)
  2441  	&& registerizable(b, t5)
  2442  	&& o4 == t5.Size()
  2443  	&& o3-o4 == t4.Size()
  2444  	&& o2-o3 == t3.Size()
  2445  	&& n == t2.Size() + t3.Size() + t4.Size() + t5.Size()
  2446  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2447  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2448  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2449  				(Store {t5} (OffPtr <tt5> [0] dst) d4 mem))))
  2450  
  2451  // Same thing but with VarDef in the middle.
  2452  (Move {t1} [n] dst p1
  2453  	mem:(VarDef
  2454  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2455  			(Store {t3} op3:(OffPtr <tt3> [0] p3) d2 _))))
  2456  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2457  	&& t2.Alignment() <= t1.Alignment()
  2458  	&& t3.Alignment() <= t1.Alignment()
  2459  	&& registerizable(b, t2)
  2460  	&& registerizable(b, t3)
  2461  	&& o2 == t3.Size()
  2462  	&& n == t2.Size() + t3.Size()
  2463  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2464  		(Store {t3} (OffPtr <tt3> [0] dst) d2 mem))
  2465  (Move {t1} [n] dst p1
  2466  	mem:(VarDef
  2467  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2468  			(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  2469  				(Store {t4} op4:(OffPtr <tt4> [0] p4) d3 _)))))
  2470  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2471  	&& t2.Alignment() <= t1.Alignment()
  2472  	&& t3.Alignment() <= t1.Alignment()
  2473  	&& t4.Alignment() <= t1.Alignment()
  2474  	&& registerizable(b, t2)
  2475  	&& registerizable(b, t3)
  2476  	&& registerizable(b, t4)
  2477  	&& o3 == t4.Size()
  2478  	&& o2-o3 == t3.Size()
  2479  	&& n == t2.Size() + t3.Size() + t4.Size()
  2480  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2481  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2482  			(Store {t4} (OffPtr <tt4> [0] dst) d3 mem)))
  2483  (Move {t1} [n] dst p1
  2484  	mem:(VarDef
  2485  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2486  			(Store {t3} op3:(OffPtr <tt3> [o3] p3) d2
  2487  				(Store {t4} op4:(OffPtr <tt4> [o4] p4) d3
  2488  					(Store {t5} op5:(OffPtr <tt5> [0] p5) d4 _))))))
  2489  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2490  	&& t2.Alignment() <= t1.Alignment()
  2491  	&& t3.Alignment() <= t1.Alignment()
  2492  	&& t4.Alignment() <= t1.Alignment()
  2493  	&& t5.Alignment() <= t1.Alignment()
  2494  	&& registerizable(b, t2)
  2495  	&& registerizable(b, t3)
  2496  	&& registerizable(b, t4)
  2497  	&& registerizable(b, t5)
  2498  	&& o4 == t5.Size()
  2499  	&& o3-o4 == t4.Size()
  2500  	&& o2-o3 == t3.Size()
  2501  	&& n == t2.Size() + t3.Size() + t4.Size() + t5.Size()
  2502  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2503  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2504  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2505  				(Store {t5} (OffPtr <tt5> [0] dst) d4 mem))))
  2506  
  2507  // Prefer to Zero and Store than to Move.
  2508  (Move {t1} [n] dst p1
  2509  	mem:(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2510  		(Zero {t3} [n] p3 _)))
  2511  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2512  	&& t2.Alignment() <= t1.Alignment()
  2513  	&& t3.Alignment() <= t1.Alignment()
  2514  	&& registerizable(b, t2)
  2515  	&& n >= o2 + t2.Size()
  2516  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2517  		(Zero {t1} [n] dst mem))
  2518  (Move {t1} [n] dst p1
  2519  	mem:(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2520  		(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2521  			(Zero {t4} [n] p4 _))))
  2522  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2523  	&& t2.Alignment() <= t1.Alignment()
  2524  	&& t3.Alignment() <= t1.Alignment()
  2525  	&& t4.Alignment() <= t1.Alignment()
  2526  	&& registerizable(b, t2)
  2527  	&& registerizable(b, t3)
  2528  	&& n >= o2 + t2.Size()
  2529  	&& n >= o3 + t3.Size()
  2530  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2531  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2532  			(Zero {t1} [n] dst mem)))
  2533  (Move {t1} [n] dst p1
  2534  	mem:(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2535  		(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2536  			(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2537  				(Zero {t5} [n] p5 _)))))
  2538  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2539  	&& t2.Alignment() <= t1.Alignment()
  2540  	&& t3.Alignment() <= t1.Alignment()
  2541  	&& t4.Alignment() <= t1.Alignment()
  2542  	&& t5.Alignment() <= t1.Alignment()
  2543  	&& registerizable(b, t2)
  2544  	&& registerizable(b, t3)
  2545  	&& registerizable(b, t4)
  2546  	&& n >= o2 + t2.Size()
  2547  	&& n >= o3 + t3.Size()
  2548  	&& n >= o4 + t4.Size()
  2549  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2550  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2551  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2552  				(Zero {t1} [n] dst mem))))
  2553  (Move {t1} [n] dst p1
  2554  	mem:(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2555  		(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2556  			(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2557  				(Store {t5} (OffPtr <tt5> [o5] p5) d4
  2558  					(Zero {t6} [n] p6 _))))))
  2559  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5) && isSamePtr(p5, p6)
  2560  	&& t2.Alignment() <= t1.Alignment()
  2561  	&& t3.Alignment() <= t1.Alignment()
  2562  	&& t4.Alignment() <= t1.Alignment()
  2563  	&& t5.Alignment() <= t1.Alignment()
  2564  	&& t6.Alignment() <= t1.Alignment()
  2565  	&& registerizable(b, t2)
  2566  	&& registerizable(b, t3)
  2567  	&& registerizable(b, t4)
  2568  	&& registerizable(b, t5)
  2569  	&& n >= o2 + t2.Size()
  2570  	&& n >= o3 + t3.Size()
  2571  	&& n >= o4 + t4.Size()
  2572  	&& n >= o5 + t5.Size()
  2573  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2574  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2575  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2576  				(Store {t5} (OffPtr <tt5> [o5] dst) d4
  2577  					(Zero {t1} [n] dst mem)))))
  2578  (Move {t1} [n] dst p1
  2579  	mem:(VarDef
  2580  		(Store {t2} op2:(OffPtr <tt2> [o2] p2) d1
  2581  			(Zero {t3} [n] p3 _))))
  2582  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3)
  2583  	&& t2.Alignment() <= t1.Alignment()
  2584  	&& t3.Alignment() <= t1.Alignment()
  2585  	&& registerizable(b, t2)
  2586  	&& n >= o2 + t2.Size()
  2587  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2588  		(Zero {t1} [n] dst mem))
  2589  (Move {t1} [n] dst p1
  2590  	mem:(VarDef
  2591  		(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2592  			(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2593  				(Zero {t4} [n] p4 _)))))
  2594  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4)
  2595  	&& t2.Alignment() <= t1.Alignment()
  2596  	&& t3.Alignment() <= t1.Alignment()
  2597  	&& t4.Alignment() <= t1.Alignment()
  2598  	&& registerizable(b, t2)
  2599  	&& registerizable(b, t3)
  2600  	&& n >= o2 + t2.Size()
  2601  	&& n >= o3 + t3.Size()
  2602  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2603  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2604  			(Zero {t1} [n] dst mem)))
  2605  (Move {t1} [n] dst p1
  2606  	mem:(VarDef
  2607  		(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2608  			(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2609  				(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2610  					(Zero {t5} [n] p5 _))))))
  2611  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5)
  2612  	&& t2.Alignment() <= t1.Alignment()
  2613  	&& t3.Alignment() <= t1.Alignment()
  2614  	&& t4.Alignment() <= t1.Alignment()
  2615  	&& t5.Alignment() <= t1.Alignment()
  2616  	&& registerizable(b, t2)
  2617  	&& registerizable(b, t3)
  2618  	&& registerizable(b, t4)
  2619  	&& n >= o2 + t2.Size()
  2620  	&& n >= o3 + t3.Size()
  2621  	&& n >= o4 + t4.Size()
  2622  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2623  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2624  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2625  				(Zero {t1} [n] dst mem))))
  2626  (Move {t1} [n] dst p1
  2627  	mem:(VarDef
  2628  		(Store {t2} (OffPtr <tt2> [o2] p2) d1
  2629  			(Store {t3} (OffPtr <tt3> [o3] p3) d2
  2630  				(Store {t4} (OffPtr <tt4> [o4] p4) d3
  2631  					(Store {t5} (OffPtr <tt5> [o5] p5) d4
  2632  						(Zero {t6} [n] p6 _)))))))
  2633  	&& isSamePtr(p1, p2) && isSamePtr(p2, p3) && isSamePtr(p3, p4) && isSamePtr(p4, p5) && isSamePtr(p5, p6)
  2634  	&& t2.Alignment() <= t1.Alignment()
  2635  	&& t3.Alignment() <= t1.Alignment()
  2636  	&& t4.Alignment() <= t1.Alignment()
  2637  	&& t5.Alignment() <= t1.Alignment()
  2638  	&& t6.Alignment() <= t1.Alignment()
  2639  	&& registerizable(b, t2)
  2640  	&& registerizable(b, t3)
  2641  	&& registerizable(b, t4)
  2642  	&& registerizable(b, t5)
  2643  	&& n >= o2 + t2.Size()
  2644  	&& n >= o3 + t3.Size()
  2645  	&& n >= o4 + t4.Size()
  2646  	&& n >= o5 + t5.Size()
  2647  	=> (Store {t2} (OffPtr <tt2> [o2] dst) d1
  2648  		(Store {t3} (OffPtr <tt3> [o3] dst) d2
  2649  			(Store {t4} (OffPtr <tt4> [o4] dst) d3
  2650  				(Store {t5} (OffPtr <tt5> [o5] dst) d4
  2651  					(Zero {t1} [n] dst mem)))))
  2652  
  2653  (SelectN [0] call:(StaticLECall {sym} a x)) && needRaceCleanup(sym, call) && clobber(call) => x
  2654  (SelectN [0] call:(StaticLECall {sym} x)) && needRaceCleanup(sym, call) && clobber(call) => x
  2655  
  2656  // When rewriting append to growslice, we use as the new length the result of
  2657  // growslice so that we don't have to spill/restore the new length around the growslice call.
  2658  // The exception here is that if the new length is a constant, avoiding spilling it
  2659  // is pointless and its constantness is sometimes useful for subsequent optimizations.
  2660  // See issue 56440.
  2661  // Note there are 2 rules here, one for the pre-decomposed []T result and one for
  2662  // the post-decomposed (*T,int,int) result. (The latter is generated after call expansion.)
  2663  (SliceLen (SelectN [0] (StaticLECall {sym} _ newLen:(Const(64|32)) _ _ _ _))) && isSameCall(sym, "runtime.growslice") => newLen
  2664  (SelectN [1] (StaticCall {sym} _ newLen:(Const(64|32)) _ _ _ _)) && v.Type.IsInteger() && isSameCall(sym, "runtime.growslice") => newLen
  2665  
  2666  // Collapse moving A -> B -> C into just A -> C.
  2667  // Later passes (deadstore, elim unread auto) will remove the A -> B move, if possible.
  2668  // This happens most commonly when B is an autotmp inserted earlier
  2669  // during compilation to ensure correctness.
  2670  // Take care that overlapping moves are preserved.
  2671  // Restrict this optimization to the stack, to avoid duplicating loads from the heap;
  2672  // see CL 145208 for discussion.
  2673  (Move {t1} [s] dst tmp1 midmem:(Move {t2} [s] tmp2 src _))
  2674  	&& t1.Compare(t2) == types.CMPeq
  2675  	&& isSamePtr(tmp1, tmp2)
  2676  	&& isStackPtr(src) && !isVolatile(src)
  2677  	&& disjoint(src, s, tmp2, s)
  2678  	&& (disjoint(src, s, dst, s) || isInlinableMemmove(dst, src, s, config))
  2679  	=> (Move {t1} [s] dst src midmem)
  2680  
  2681  // Same, but for large types that require VarDefs.
  2682  (Move {t1} [s] dst tmp1 midmem:(VarDef (Move {t2} [s] tmp2 src _)))
  2683  	&& t1.Compare(t2) == types.CMPeq
  2684  	&& isSamePtr(tmp1, tmp2)
  2685  	&& isStackPtr(src) && !isVolatile(src)
  2686  	&& disjoint(src, s, tmp2, s)
  2687  	&& (disjoint(src, s, dst, s) || isInlinableMemmove(dst, src, s, config))
  2688  	=> (Move {t1} [s] dst src midmem)
  2689  
  2690  // Don't zero the same bits twice.
  2691  (Zero {t} [s] dst1 zero:(Zero {t} [s] dst2 _)) && isSamePtr(dst1, dst2) => zero
  2692  (Zero {t} [s] dst1 vardef:(VarDef (Zero {t} [s] dst2 _))) && isSamePtr(dst1, dst2) => vardef
  2693  
  2694  // Elide self-moves. This only happens rarely (e.g test/fixedbugs/bug277.go).
  2695  // However, this rule is needed to prevent the previous rule from looping forever in such cases.
  2696  (Move dst src mem) && isSamePtr(dst, src) => mem
  2697  
  2698  // Constant rotate detection.
  2699  ((Add64|Or64|Xor64) (Lsh64x64 x z:(Const64 <t> [c])) (Rsh64Ux64 x (Const64 [d]))) && c < 64 && d == 64-c && canRotate(config, 64) => (RotateLeft64 x z)
  2700  ((Add32|Or32|Xor32) (Lsh32x64 x z:(Const64 <t> [c])) (Rsh32Ux64 x (Const64 [d]))) && c < 32 && d == 32-c && canRotate(config, 32) => (RotateLeft32 x z)
  2701  ((Add16|Or16|Xor16) (Lsh16x64 x z:(Const64 <t> [c])) (Rsh16Ux64 x (Const64 [d]))) && c < 16 && d == 16-c && canRotate(config, 16) => (RotateLeft16 x z)
  2702  ((Add8|Or8|Xor8) (Lsh8x64 x z:(Const64 <t> [c])) (Rsh8Ux64 x (Const64 [d]))) && c < 8 && d == 8-c && canRotate(config, 8) => (RotateLeft8 x z)
  2703  
  2704  // Non-constant rotate detection.
  2705  // We use shiftIsBounded to make sure that neither of the shifts are >64.
  2706  // Note: these rules are subtle when the shift amounts are 0/64, as Go shifts
  2707  // are different from most native shifts. But it works out.
  2708  ((Add64|Or64|Xor64) left:(Lsh64x64 x y) right:(Rsh64Ux64 x (Sub64 (Const64 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2709  ((Add64|Or64|Xor64) left:(Lsh64x32 x y) right:(Rsh64Ux32 x (Sub32 (Const32 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2710  ((Add64|Or64|Xor64) left:(Lsh64x16 x y) right:(Rsh64Ux16 x (Sub16 (Const16 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2711  ((Add64|Or64|Xor64) left:(Lsh64x8  x y) right:(Rsh64Ux8  x (Sub8  (Const8  [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x y)
  2712  
  2713  ((Add64|Or64|Xor64) right:(Rsh64Ux64 x y) left:(Lsh64x64 x z:(Sub64 (Const64 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2714  ((Add64|Or64|Xor64) right:(Rsh64Ux32 x y) left:(Lsh64x32 x z:(Sub32 (Const32 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2715  ((Add64|Or64|Xor64) right:(Rsh64Ux16 x y) left:(Lsh64x16 x z:(Sub16 (Const16 [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2716  ((Add64|Or64|Xor64) right:(Rsh64Ux8  x y) left:(Lsh64x8  x z:(Sub8  (Const8  [64]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 64) => (RotateLeft64 x z)
  2717  
  2718  ((Add32|Or32|Xor32) left:(Lsh32x64 x y) right:(Rsh32Ux64 x (Sub64 (Const64 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2719  ((Add32|Or32|Xor32) left:(Lsh32x32 x y) right:(Rsh32Ux32 x (Sub32 (Const32 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2720  ((Add32|Or32|Xor32) left:(Lsh32x16 x y) right:(Rsh32Ux16 x (Sub16 (Const16 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2721  ((Add32|Or32|Xor32) left:(Lsh32x8  x y) right:(Rsh32Ux8  x (Sub8  (Const8  [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x y)
  2722  
  2723  ((Add32|Or32|Xor32) right:(Rsh32Ux64 x y) left:(Lsh32x64 x z:(Sub64 (Const64 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2724  ((Add32|Or32|Xor32) right:(Rsh32Ux32 x y) left:(Lsh32x32 x z:(Sub32 (Const32 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2725  ((Add32|Or32|Xor32) right:(Rsh32Ux16 x y) left:(Lsh32x16 x z:(Sub16 (Const16 [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2726  ((Add32|Or32|Xor32) right:(Rsh32Ux8  x y) left:(Lsh32x8  x z:(Sub8  (Const8  [32]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 32) => (RotateLeft32 x z)
  2727  
  2728  ((Add16|Or16|Xor16) left:(Lsh16x64 x y) right:(Rsh16Ux64 x (Sub64 (Const64 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2729  ((Add16|Or16|Xor16) left:(Lsh16x32 x y) right:(Rsh16Ux32 x (Sub32 (Const32 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2730  ((Add16|Or16|Xor16) left:(Lsh16x16 x y) right:(Rsh16Ux16 x (Sub16 (Const16 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2731  ((Add16|Or16|Xor16) left:(Lsh16x8  x y) right:(Rsh16Ux8  x (Sub8  (Const8  [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x y)
  2732  
  2733  ((Add16|Or16|Xor16) right:(Rsh16Ux64 x y) left:(Lsh16x64 x z:(Sub64 (Const64 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2734  ((Add16|Or16|Xor16) right:(Rsh16Ux32 x y) left:(Lsh16x32 x z:(Sub32 (Const32 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2735  ((Add16|Or16|Xor16) right:(Rsh16Ux16 x y) left:(Lsh16x16 x z:(Sub16 (Const16 [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2736  ((Add16|Or16|Xor16) right:(Rsh16Ux8  x y) left:(Lsh16x8  x z:(Sub8  (Const8  [16]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 16) => (RotateLeft16 x z)
  2737  
  2738  ((Add8|Or8|Xor8) left:(Lsh8x64 x y) right:(Rsh8Ux64 x (Sub64 (Const64 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2739  ((Add8|Or8|Xor8) left:(Lsh8x32 x y) right:(Rsh8Ux32 x (Sub32 (Const32 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2740  ((Add8|Or8|Xor8) left:(Lsh8x16 x y) right:(Rsh8Ux16 x (Sub16 (Const16 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2741  ((Add8|Or8|Xor8) left:(Lsh8x8  x y) right:(Rsh8Ux8  x (Sub8  (Const8  [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x y)
  2742  
  2743  ((Add8|Or8|Xor8) right:(Rsh8Ux64 x y) left:(Lsh8x64 x z:(Sub64 (Const64 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2744  ((Add8|Or8|Xor8) right:(Rsh8Ux32 x y) left:(Lsh8x32 x z:(Sub32 (Const32 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2745  ((Add8|Or8|Xor8) right:(Rsh8Ux16 x y) left:(Lsh8x16 x z:(Sub16 (Const16 [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2746  ((Add8|Or8|Xor8) right:(Rsh8Ux8  x y) left:(Lsh8x8  x z:(Sub8  (Const8  [8]) y))) && (shiftIsBounded(left) || shiftIsBounded(right)) && canRotate(config, 8) => (RotateLeft8 x z)
  2747  
  2748  // Rotating by y&c, with c a mask that doesn't change the bottom bits, is the same as rotating by y.
  2749  (RotateLeft64 x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&63 == 63 => (RotateLeft64 x y)
  2750  (RotateLeft32 x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&31 == 31 => (RotateLeft32 x y)
  2751  (RotateLeft16 x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&15 == 15 => (RotateLeft16 x y)
  2752  (RotateLeft8  x (And(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&7  == 7  => (RotateLeft8  x y)
  2753  
  2754  // Rotating by -(y&c), with c a mask that doesn't change the bottom bits, is the same as rotating by -y.
  2755  (RotateLeft64 x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&63 == 63 => (RotateLeft64 x (Neg(64|32|16|8) <y.Type> y))
  2756  (RotateLeft32 x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&31 == 31 => (RotateLeft32 x (Neg(64|32|16|8) <y.Type> y))
  2757  (RotateLeft16 x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&15 == 15 => (RotateLeft16 x (Neg(64|32|16|8) <y.Type> y))
  2758  (RotateLeft8  x (Neg(64|32|16|8) (And(64|32|16|8) y (Const(64|32|16|8) [c])))) && c&7  == 7  => (RotateLeft8  x (Neg(64|32|16|8) <y.Type> y))
  2759  
  2760  // Rotating by y+c, with c a multiple of the value width, is the same as rotating by y.
  2761  (RotateLeft64 x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&63 == 0 => (RotateLeft64 x y)
  2762  (RotateLeft32 x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&31 == 0 => (RotateLeft32 x y)
  2763  (RotateLeft16 x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&15 == 0 => (RotateLeft16 x y)
  2764  (RotateLeft8  x (Add(64|32|16|8) y (Const(64|32|16|8) [c]))) && c&7  == 0 => (RotateLeft8  x y)
  2765  
  2766  // Rotating by c-y, with c a multiple of the value width, is the same as rotating by -y.
  2767  (RotateLeft64 x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&63 == 0 => (RotateLeft64 x (Neg(64|32|16|8) <y.Type> y))
  2768  (RotateLeft32 x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&31 == 0 => (RotateLeft32 x (Neg(64|32|16|8) <y.Type> y))
  2769  (RotateLeft16 x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&15 == 0 => (RotateLeft16 x (Neg(64|32|16|8) <y.Type> y))
  2770  (RotateLeft8  x (Sub(64|32|16|8) (Const(64|32|16|8) [c]) y)) && c&7  == 0 => (RotateLeft8  x (Neg(64|32|16|8) <y.Type> y))
  2771  
  2772  // Ensure we don't do Const64 rotates in a 32-bit system.
  2773  (RotateLeft64 x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft64 x (Const32 <t> [int32(c)]))
  2774  (RotateLeft32 x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft32 x (Const32 <t> [int32(c)]))
  2775  (RotateLeft16 x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft16 x (Const32 <t> [int32(c)]))
  2776  (RotateLeft8  x (Const64 <t> [c])) && config.PtrSize == 4 => (RotateLeft8  x (Const32 <t> [int32(c)]))
  2777  
  2778  // Rotating by c, then by d, is the same as rotating by c+d.
  2779  // We're trading a rotate for an add, which seems generally a good choice. It is especially good when c and d are constants.
  2780  // This rule is a bit tricky as c and d might be different widths. We handle only cases where they are the same width.
  2781  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 8 && d.Type.Size() == 8 => (RotateLeft(64|32|16|8) x (Add64 <c.Type> c d))
  2782  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 4 && d.Type.Size() == 4 => (RotateLeft(64|32|16|8) x (Add32 <c.Type> c d))
  2783  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 2 && d.Type.Size() == 2 => (RotateLeft(64|32|16|8) x (Add16 <c.Type> c d))
  2784  (RotateLeft(64|32|16|8) (RotateLeft(64|32|16|8) x c) d) && c.Type.Size() == 1 && d.Type.Size() == 1 => (RotateLeft(64|32|16|8) x (Add8  <c.Type> c d))
  2785  
  2786  // Loading constant values from dictionaries and itabs.
  2787  (Load <t> (OffPtr [off]                       (Addr {s} sb)       ) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
  2788  (Load <t> (OffPtr [off]              (Convert (Addr {s} sb) _)    ) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
  2789  (Load <t> (OffPtr [off] (ITab (IMake          (Addr {s} sb)    _))) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
  2790  (Load <t> (OffPtr [off] (ITab (IMake (Convert (Addr {s} sb) _) _))) _) && t.IsUintptr() && isFixedSym(s, off) => (Addr {fixedSym(b.Func, s, off)} sb)
  2791  
  2792  // Loading constant values from runtime._type.hash.
  2793  (Load <t> (OffPtr [off]                       (Addr {sym} _)       ) _) && t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off) => (Const32 [fixed32(config, sym, off)])
  2794  (Load <t> (OffPtr [off]              (Convert (Addr {sym} _) _)    ) _) && t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off) => (Const32 [fixed32(config, sym, off)])
  2795  (Load <t> (OffPtr [off] (ITab (IMake          (Addr {sym} _)    _))) _) && t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off) => (Const32 [fixed32(config, sym, off)])
  2796  (Load <t> (OffPtr [off] (ITab (IMake (Convert (Addr {sym} _) _) _))) _) && t.IsInteger() && t.Size() == 4 && isFixed32(config, sym, off) => (Const32 [fixed32(config, sym, off)])
  2797  
  2798  // Calling cmpstring a second time with the same arguments in the
  2799  // same memory state can reuse the results of the first call.
  2800  // See issue 61725.
  2801  // Note that this could pretty easily generalize to any pure function.
  2802  (SelectN [0] (StaticLECall {f} x y (SelectN [1] c:(StaticLECall {g} x y mem))))
  2803    && isSameCall(f, "runtime.cmpstring")
  2804    && isSameCall(g, "runtime.cmpstring")
  2805  => @c.Block (SelectN [0] <typ.Int> c)
  2806  
  2807  // If we don't use the result of cmpstring, might as well not call it.
  2808  // Note that this could pretty easily generalize to any pure function.
  2809  (SelectN [1] c:(StaticLECall {f} _ _ mem)) && c.Uses == 1 && isSameCall(f, "runtime.cmpstring") && clobber(c) => mem
  2810  

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