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Text file src/cmd/compile/internal/ssa/_gen/RISCV64.rules

Documentation: cmd/compile/internal/ssa/_gen

     1// Copyright 2016 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// Lowering arithmetic
     6(Add(Ptr|64|32|16|8) ...) => (ADD ...)
     7(Add(64|32)F ...) => (FADD(D|S) ...)
     8
     9(Sub(Ptr|64|32|16|8) ...) => (SUB ...)
    10(Sub(64|32)F ...) => (FSUB(D|S) ...)
    11
    12(Mul64 ...) => (MUL  ...)
    13(Mul64uhilo ...) => (LoweredMuluhilo ...)
    14(Mul64uover ...) => (LoweredMuluover ...)
    15(Mul32 ...) => (MULW ...)
    16(Mul16 x y) => (MULW (SignExt16to32 x) (SignExt16to32 y))
    17(Mul8 x y)  => (MULW (SignExt8to32 x)  (SignExt8to32 y))
    18(Mul(64|32)F ...) => (FMUL(D|S) ...)
    19
    20(Div(64|32)F ...) => (FDIV(D|S) ...)
    21
    22(Div64 x y [false])  => (DIV x y)
    23(Div64u ...) => (DIVU ...)
    24(Div32 x y [false])  => (DIVW x y)
    25(Div32u ...) => (DIVUW ...)
    26(Div16 x y [false])  => (DIVW  (SignExt16to32 x) (SignExt16to32 y))
    27(Div16u x y) => (DIVUW (ZeroExt16to32 x) (ZeroExt16to32 y))
    28(Div8 x y)   => (DIVW  (SignExt8to32 x)  (SignExt8to32 y))
    29(Div8u x y)  => (DIVUW (ZeroExt8to32 x)  (ZeroExt8to32 y))
    30
    31(Hmul64 ...)  => (MULH  ...)
    32(Hmul64u ...) => (MULHU ...)
    33(Hmul32 x y)  => (SRAI [32] (MUL  (SignExt32to64 x) (SignExt32to64 y)))
    34(Hmul32u x y) => (SRLI [32] (MUL  (ZeroExt32to64 x) (ZeroExt32to64 y)))
    35
    36(Select0 (Add64carry x y c)) => (ADD (ADD <typ.UInt64> x y) c)
    37(Select1 (Add64carry x y c)) =>
    38	(OR (SLTU <typ.UInt64> s:(ADD <typ.UInt64> x y) x) (SLTU <typ.UInt64> (ADD <typ.UInt64> s c) s))
    39
    40(Select0 (Sub64borrow x y c)) => (SUB (SUB <typ.UInt64> x y) c)
    41(Select1 (Sub64borrow x y c)) =>
    42	(OR (SLTU <typ.UInt64> x s:(SUB <typ.UInt64> x y)) (SLTU <typ.UInt64> s (SUB <typ.UInt64> s c)))
    43
    44// (x + y) / 2 => (x / 2) + (y / 2) + (x & y & 1)
    45(Avg64u <t> x y) => (ADD (ADD <t> (SRLI <t> [1] x) (SRLI <t> [1] y)) (ANDI <t> [1] (AND <t> x y)))
    46
    47(Mod64 x y [false])  => (REM x y)
    48(Mod64u ...) => (REMU  ...)
    49(Mod32 x y [false])  => (REMW x y)
    50(Mod32u ...) => (REMUW ...)
    51(Mod16 x y [false])  => (REMW  (SignExt16to32 x) (SignExt16to32 y))
    52(Mod16u x y) => (REMUW (ZeroExt16to32 x) (ZeroExt16to32 y))
    53(Mod8 x y)   => (REMW  (SignExt8to32  x) (SignExt8to32  y))
    54(Mod8u x y)  => (REMUW (ZeroExt8to32  x) (ZeroExt8to32  y))
    55
    56(And(64|32|16|8) ...) => (AND ...)
    57(Or(64|32|16|8) ...) => (OR ...)
    58(Xor(64|32|16|8) ...) => (XOR ...)
    59
    60(Neg(64|32|16|8) ...) => (NEG ...)
    61(Neg(64|32)F ...) => (FNEG(D|S) ...)
    62
    63(Com(64|32|16|8) ...) => (NOT ...)
    64
    65
    66(Sqrt ...) => (FSQRTD ...)
    67(Sqrt32 ...) => (FSQRTS ...)
    68
    69(Copysign ...) => (FSGNJD ...)
    70
    71(Abs ...) => (FABSD ...)
    72
    73(FMA ...) => (FMADDD ...)
    74
    75// Sign and zero extension.
    76
    77(SignExt8to16  ...) => (MOVBreg ...)
    78(SignExt8to32  ...) => (MOVBreg ...)
    79(SignExt8to64  ...) => (MOVBreg ...)
    80(SignExt16to32 ...) => (MOVHreg ...)
    81(SignExt16to64 ...) => (MOVHreg ...)
    82(SignExt32to64 ...) => (MOVWreg ...)
    83
    84(ZeroExt8to16  ...) => (MOVBUreg ...)
    85(ZeroExt8to32  ...) => (MOVBUreg ...)
    86(ZeroExt8to64  ...) => (MOVBUreg ...)
    87(ZeroExt16to32 ...) => (MOVHUreg ...)
    88(ZeroExt16to64 ...) => (MOVHUreg ...)
    89(ZeroExt32to64 ...) => (MOVWUreg ...)
    90
    91(Cvt32to32F ...) => (FCVTSW ...)
    92(Cvt32to64F ...) => (FCVTDW ...)
    93(Cvt64to32F ...) => (FCVTSL ...)
    94(Cvt64to64F ...) => (FCVTDL ...)
    95
    96(Cvt32Fto32 ...) => (FCVTWS ...)
    97(Cvt32Fto64 ...) => (FCVTLS ...)
    98(Cvt64Fto32 ...) => (FCVTWD ...)
    99(Cvt64Fto64 ...) => (FCVTLD ...)
   100
   101(Cvt32Fto64F ...) => (FCVTDS ...)
   102(Cvt64Fto32F ...) => (FCVTSD ...)
   103
   104(CvtBoolToUint8 ...) => (Copy ...)
   105
   106(Round(32|64)F ...) => (LoweredRound(32|64)F ...)
   107
   108(Slicemask <t> x) => (SRAI [63] (NEG <t> x))
   109
   110// Truncations
   111// We ignore the unused high parts of registers, so truncates are just copies.
   112(Trunc16to8  ...) => (Copy ...)
   113(Trunc32to8  ...) => (Copy ...)
   114(Trunc32to16 ...) => (Copy ...)
   115(Trunc64to8  ...) => (Copy ...)
   116(Trunc64to16 ...) => (Copy ...)
   117(Trunc64to32 ...) => (Copy ...)
   118
   119// Shifts
   120
   121// SLL only considers the bottom 6 bits of y. If y > 64, the result should
   122// always be 0.
   123//
   124// Breaking down the operation:
   125//
   126// (SLL x y) generates x << (y & 63).
   127//
   128// If y < 64, this is the value we want. Otherwise, we want zero.
   129//
   130// So, we AND with -1 * uint64(y < 64), which is 0xfffff... if y < 64 and 0 otherwise.
   131(Lsh8x8   <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg8  <t> (SLTIU <t> [64] (ZeroExt8to64  y))))
   132(Lsh8x16  <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg8  <t> (SLTIU <t> [64] (ZeroExt16to64 y))))
   133(Lsh8x32  <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg8  <t> (SLTIU <t> [64] (ZeroExt32to64 y))))
   134(Lsh8x64  <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg8  <t> (SLTIU <t> [64] y)))
   135(Lsh16x8  <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg16 <t> (SLTIU <t> [64] (ZeroExt8to64  y))))
   136(Lsh16x16 <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg16 <t> (SLTIU <t> [64] (ZeroExt16to64 y))))
   137(Lsh16x32 <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg16 <t> (SLTIU <t> [64] (ZeroExt32to64 y))))
   138(Lsh16x64 <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg16 <t> (SLTIU <t> [64] y)))
   139(Lsh32x8  <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg32 <t> (SLTIU <t> [64] (ZeroExt8to64  y))))
   140(Lsh32x16 <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg32 <t> (SLTIU <t> [64] (ZeroExt16to64 y))))
   141(Lsh32x32 <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg32 <t> (SLTIU <t> [64] (ZeroExt32to64 y))))
   142(Lsh32x64 <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg32 <t> (SLTIU <t> [64] y)))
   143(Lsh64x8  <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg64 <t> (SLTIU <t> [64] (ZeroExt8to64  y))))
   144(Lsh64x16 <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg64 <t> (SLTIU <t> [64] (ZeroExt16to64 y))))
   145(Lsh64x32 <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg64 <t> (SLTIU <t> [64] (ZeroExt32to64 y))))
   146(Lsh64x64 <t> x y) && !shiftIsBounded(v) => (AND (SLL <t> x y) (Neg64 <t> (SLTIU <t> [64] y)))
   147
   148(Lsh8x(64|32|16|8)  x y) && shiftIsBounded(v) => (SLL x y)
   149(Lsh16x(64|32|16|8) x y) && shiftIsBounded(v) => (SLL x y)
   150(Lsh32x(64|32|16|8) x y) && shiftIsBounded(v) => (SLL x y)
   151(Lsh64x(64|32|16|8) x y) && shiftIsBounded(v) => (SLL x y)
   152
   153// SRL only considers the bottom 6 bits of y, similarly SRLW only considers the
   154// bottom 5 bits of y. Ensure that the result is always zero if the shift exceeds
   155// the maximum value. See Lsh above for a detailed description.
   156(Rsh8Ux8   <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t> (ZeroExt8to64  x) y) (Neg8  <t> (SLTIU <t> [64] (ZeroExt8to64  y))))
   157(Rsh8Ux16  <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t> (ZeroExt8to64  x) y) (Neg8  <t> (SLTIU <t> [64] (ZeroExt16to64 y))))
   158(Rsh8Ux32  <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t> (ZeroExt8to64  x) y) (Neg8  <t> (SLTIU <t> [64] (ZeroExt32to64 y))))
   159(Rsh8Ux64  <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t> (ZeroExt8to64  x) y) (Neg8  <t> (SLTIU <t> [64] y)))
   160(Rsh16Ux8  <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t> (ZeroExt16to64 x) y) (Neg16 <t> (SLTIU <t> [64] (ZeroExt8to64  y))))
   161(Rsh16Ux16 <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t> (ZeroExt16to64 x) y) (Neg16 <t> (SLTIU <t> [64] (ZeroExt16to64 y))))
   162(Rsh16Ux32 <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t> (ZeroExt16to64 x) y) (Neg16 <t> (SLTIU <t> [64] (ZeroExt32to64 y))))
   163(Rsh16Ux64 <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t> (ZeroExt16to64 x) y) (Neg16 <t> (SLTIU <t> [64] y)))
   164(Rsh32Ux8  <t> x y) && !shiftIsBounded(v) => (AND (SRLW <t>  x                y) (Neg32 <t> (SLTIU <t> [32] (ZeroExt8to64  y))))
   165(Rsh32Ux16 <t> x y) && !shiftIsBounded(v) => (AND (SRLW <t>  x                y) (Neg32 <t> (SLTIU <t> [32] (ZeroExt16to64 y))))
   166(Rsh32Ux32 <t> x y) && !shiftIsBounded(v) => (AND (SRLW <t>  x                y) (Neg32 <t> (SLTIU <t> [32] (ZeroExt32to64 y))))
   167(Rsh32Ux64 <t> x y) && !shiftIsBounded(v) => (AND (SRLW <t>  x                y) (Neg32 <t> (SLTIU <t> [32] y)))
   168(Rsh64Ux8  <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t>  x                y) (Neg64 <t> (SLTIU <t> [64] (ZeroExt8to64  y))))
   169(Rsh64Ux16 <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t>  x                y) (Neg64 <t> (SLTIU <t> [64] (ZeroExt16to64 y))))
   170(Rsh64Ux32 <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t>  x                y) (Neg64 <t> (SLTIU <t> [64] (ZeroExt32to64 y))))
   171(Rsh64Ux64 <t> x y) && !shiftIsBounded(v) => (AND (SRL  <t>  x                y) (Neg64 <t> (SLTIU <t> [64] y)))
   172
   173(Rsh8Ux(64|32|16|8)  x y) && shiftIsBounded(v) => (SRL  (ZeroExt8to64  x) y)
   174(Rsh16Ux(64|32|16|8) x y) && shiftIsBounded(v) => (SRL  (ZeroExt16to64 x) y)
   175(Rsh32Ux(64|32|16|8) x y) && shiftIsBounded(v) => (SRLW x                 y)
   176(Rsh64Ux(64|32|16|8) x y) && shiftIsBounded(v) => (SRL  x                 y)
   177
   178// SRA only considers the bottom 6 bits of y, similarly SRAW only considers the
   179// bottom 5 bits. If y is greater than the maximum value (either 63 or 31
   180// depending on the instruction),  the result of the shift should be either 0
   181// or -1 based on the sign bit of x.
   182//
   183// We implement this by performing the max shift (-1) if y > the maximum value.
   184//
   185// We OR (uint64(y < 64) - 1) into y before passing it to SRA. This leaves
   186// us with -1 (0xffff...) if y >= 64.  Similarly, we OR (uint64(y < 32) - 1) into y
   187// before passing it to SRAW.
   188//
   189// We don't need to sign-extend the OR result, as it will be at minimum 8 bits,
   190// more than the 5 or 6 bits SRAW and SRA care about.
   191(Rsh8x8   <t> x y) && !shiftIsBounded(v) => (SRA  <t> (SignExt8to64  x) (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] (ZeroExt8to64  y)))))
   192(Rsh8x16  <t> x y) && !shiftIsBounded(v) => (SRA  <t> (SignExt8to64  x) (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] (ZeroExt16to64 y)))))
   193(Rsh8x32  <t> x y) && !shiftIsBounded(v) => (SRA  <t> (SignExt8to64  x) (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] (ZeroExt32to64 y)))))
   194(Rsh8x64  <t> x y) && !shiftIsBounded(v) => (SRA  <t> (SignExt8to64  x) (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] y))))
   195(Rsh16x8  <t> x y) && !shiftIsBounded(v) => (SRA  <t> (SignExt16to64 x) (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] (ZeroExt8to64  y)))))
   196(Rsh16x16 <t> x y) && !shiftIsBounded(v) => (SRA  <t> (SignExt16to64 x) (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] (ZeroExt16to64 y)))))
   197(Rsh16x32 <t> x y) && !shiftIsBounded(v) => (SRA  <t> (SignExt16to64 x) (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] (ZeroExt32to64 y)))))
   198(Rsh16x64 <t> x y) && !shiftIsBounded(v) => (SRA  <t> (SignExt16to64 x) (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] y))))
   199(Rsh32x8  <t> x y) && !shiftIsBounded(v) => (SRAW <t> x                 (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [32] (ZeroExt8to64  y)))))
   200(Rsh32x16 <t> x y) && !shiftIsBounded(v) => (SRAW <t> x                 (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [32] (ZeroExt16to64 y)))))
   201(Rsh32x32 <t> x y) && !shiftIsBounded(v) => (SRAW <t> x                 (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [32] (ZeroExt32to64 y)))))
   202(Rsh32x64 <t> x y) && !shiftIsBounded(v) => (SRAW <t> x                 (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [32] y))))
   203(Rsh64x8  <t> x y) && !shiftIsBounded(v) => (SRA  <t> x                 (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] (ZeroExt8to64  y)))))
   204(Rsh64x16 <t> x y) && !shiftIsBounded(v) => (SRA  <t> x                 (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] (ZeroExt16to64 y)))))
   205(Rsh64x32 <t> x y) && !shiftIsBounded(v) => (SRA  <t> x                 (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] (ZeroExt32to64 y)))))
   206(Rsh64x64 <t> x y) && !shiftIsBounded(v) => (SRA  <t> x                 (OR <y.Type> y (ADDI <y.Type> [-1] (SLTIU <y.Type> [64] y))))
   207
   208(Rsh8x(64|32|16|8)  x y) && shiftIsBounded(v) => (SRA  (SignExt8to64  x) y)
   209(Rsh16x(64|32|16|8) x y) && shiftIsBounded(v) => (SRA  (SignExt16to64 x) y)
   210(Rsh32x(64|32|16|8) x y) && shiftIsBounded(v) => (SRAW  x                y)
   211(Rsh64x(64|32|16|8) x y) && shiftIsBounded(v) => (SRA   x                y)
   212
   213// Rotates.
   214(RotateLeft8  <t> x (MOVDconst [c])) => (Or8  (Lsh8x64  <t> x (MOVDconst [c&7]))  (Rsh8Ux64  <t> x (MOVDconst [-c&7])))
   215(RotateLeft16 <t> x (MOVDconst [c])) => (Or16 (Lsh16x64 <t> x (MOVDconst [c&15])) (Rsh16Ux64 <t> x (MOVDconst [-c&15])))
   216(RotateLeft32 <t> x (MOVDconst [c])) => (Or32 (Lsh32x64 <t> x (MOVDconst [c&31])) (Rsh32Ux64 <t> x (MOVDconst [-c&31])))
   217(RotateLeft64 <t> x (MOVDconst [c])) => (Or64 (Lsh64x64 <t> x (MOVDconst [c&63])) (Rsh64Ux64 <t> x (MOVDconst [-c&63])))
   218
   219(Less64  ...) => (SLT  ...)
   220(Less32  x y) => (SLT  (SignExt32to64 x) (SignExt32to64 y))
   221(Less16  x y) => (SLT  (SignExt16to64 x) (SignExt16to64 y))
   222(Less8   x y) => (SLT  (SignExt8to64  x) (SignExt8to64  y))
   223(Less64U ...) => (SLTU ...)
   224(Less32U x y) => (SLTU (ZeroExt32to64 x) (ZeroExt32to64 y))
   225(Less16U x y) => (SLTU (ZeroExt16to64 x) (ZeroExt16to64 y))
   226(Less8U  x y) => (SLTU (ZeroExt8to64  x) (ZeroExt8to64  y))
   227(Less(64|32)F ...) => (FLT(D|S) ...)
   228
   229// Convert x <= y to !(y > x).
   230(Leq(64|32|16|8)  x y) => (Not (Less(64|32|16|8)  y x))
   231(Leq(64|32|16|8)U x y) => (Not (Less(64|32|16|8)U y x))
   232(Leq(64|32)F ...) => (FLE(D|S) ...)
   233
   234(EqPtr x y) => (SEQZ (SUB <typ.Uintptr> x y))
   235(Eq64  x y) => (SEQZ (SUB <x.Type> x y))
   236(Eq32  x y) &&  x.Type.IsSigned() => (SEQZ (SUB <x.Type> (SignExt32to64 x) (SignExt32to64 y)))
   237(Eq32  x y) && !x.Type.IsSigned() => (SEQZ (SUB <x.Type> (ZeroExt32to64 x) (ZeroExt32to64 y)))
   238(Eq16  x y) => (SEQZ (SUB <x.Type> (ZeroExt16to64 x) (ZeroExt16to64 y)))
   239(Eq8   x y) => (SEQZ (SUB <x.Type> (ZeroExt8to64  x) (ZeroExt8to64  y)))
   240(Eq(64|32)F ...) => (FEQ(D|S) ...)
   241
   242(NeqPtr x y) => (Not (EqPtr x y))
   243(Neq64  x y) => (Not (Eq64  x y))
   244(Neq32  x y) => (Not (Eq32  x y))
   245(Neq16  x y) => (Not (Eq16  x y))
   246(Neq8   x y) => (Not (Eq8   x y))
   247(Neq(64|32)F ...) => (FNE(D|S) ...)
   248
   249// Loads
   250(Load <t> ptr mem) &&  t.IsBoolean()                   => (MOVBUload ptr mem)
   251(Load <t> ptr mem) && ( is8BitInt(t) &&  t.IsSigned()) => (MOVBload  ptr mem)
   252(Load <t> ptr mem) && ( is8BitInt(t) && !t.IsSigned()) => (MOVBUload ptr mem)
   253(Load <t> ptr mem) && (is16BitInt(t) &&  t.IsSigned()) => (MOVHload  ptr mem)
   254(Load <t> ptr mem) && (is16BitInt(t) && !t.IsSigned()) => (MOVHUload ptr mem)
   255(Load <t> ptr mem) && (is32BitInt(t) &&  t.IsSigned()) => (MOVWload  ptr mem)
   256(Load <t> ptr mem) && (is32BitInt(t) && !t.IsSigned()) => (MOVWUload ptr mem)
   257(Load <t> ptr mem) && (is64BitInt(t) || isPtr(t))      => (MOVDload  ptr mem)
   258(Load <t> ptr mem) &&  is32BitFloat(t)                 => (FMOVWload ptr mem)
   259(Load <t> ptr mem) &&  is64BitFloat(t)                 => (FMOVDload ptr mem)
   260
   261// Stores
   262(Store {t} ptr val mem) && t.Size() == 1 => (MOVBstore ptr val mem)
   263(Store {t} ptr val mem) && t.Size() == 2 => (MOVHstore ptr val mem)
   264(Store {t} ptr val mem) && t.Size() == 4 && !t.IsFloat() => (MOVWstore ptr val mem)
   265(Store {t} ptr val mem) && t.Size() == 8 && !t.IsFloat() => (MOVDstore ptr val mem)
   266(Store {t} ptr val mem) && t.Size() == 4 &&  t.IsFloat() => (FMOVWstore ptr val mem)
   267(Store {t} ptr val mem) && t.Size() == 8 &&  t.IsFloat() => (FMOVDstore ptr val mem)
   268
   269// We need to fold MOVaddr into the LD/MOVDstore ops so that the live variable analysis
   270// knows what variables are being read/written by the ops.
   271(MOVBUload [off1] {sym1} (MOVaddr [off2] {sym2} base) mem) && is32Bit(int64(off1)+int64(off2)) && canMergeSym(sym1, sym2) =>
   272	(MOVBUload [off1+off2] {mergeSym(sym1,sym2)} base mem)
   273(MOVBload  [off1] {sym1} (MOVaddr [off2] {sym2} base) mem) && is32Bit(int64(off1)+int64(off2)) && canMergeSym(sym1, sym2) =>
   274	(MOVBload  [off1+off2] {mergeSym(sym1,sym2)} base mem)
   275(MOVHUload [off1] {sym1} (MOVaddr [off2] {sym2} base) mem) && is32Bit(int64(off1)+int64(off2)) && canMergeSym(sym1, sym2) =>
   276	(MOVHUload [off1+off2] {mergeSym(sym1,sym2)} base mem)
   277(MOVHload  [off1] {sym1} (MOVaddr [off2] {sym2} base) mem) && is32Bit(int64(off1)+int64(off2)) && canMergeSym(sym1, sym2) =>
   278	(MOVHload  [off1+off2] {mergeSym(sym1,sym2)} base mem)
   279(MOVWUload [off1] {sym1} (MOVaddr [off2] {sym2} base) mem) && is32Bit(int64(off1)+int64(off2)) && canMergeSym(sym1, sym2) =>
   280	(MOVWUload [off1+off2] {mergeSym(sym1,sym2)} base mem)
   281(MOVWload  [off1] {sym1} (MOVaddr [off2] {sym2} base) mem) && is32Bit(int64(off1)+int64(off2)) && canMergeSym(sym1, sym2) =>
   282	(MOVWload  [off1+off2] {mergeSym(sym1,sym2)} base mem)
   283(MOVDload  [off1] {sym1} (MOVaddr [off2] {sym2} base) mem) && is32Bit(int64(off1)+int64(off2)) && canMergeSym(sym1, sym2) =>
   284	(MOVDload  [off1+off2] {mergeSym(sym1,sym2)} base mem)
   285
   286(MOVBstore [off1] {sym1} (MOVaddr [off2] {sym2} base) val mem) && is32Bit(int64(off1)+int64(off2)) && canMergeSym(sym1, sym2) =>
   287	(MOVBstore [off1+off2] {mergeSym(sym1,sym2)} base val mem)
   288(MOVHstore [off1] {sym1} (MOVaddr [off2] {sym2} base) val mem) && is32Bit(int64(off1)+int64(off2)) && canMergeSym(sym1, sym2) =>
   289	(MOVHstore [off1+off2] {mergeSym(sym1,sym2)} base val mem)
   290(MOVWstore [off1] {sym1} (MOVaddr [off2] {sym2} base) val mem) && is32Bit(int64(off1)+int64(off2)) && canMergeSym(sym1, sym2) =>
   291	(MOVWstore [off1+off2] {mergeSym(sym1,sym2)} base val mem)
   292(MOVDstore [off1] {sym1} (MOVaddr [off2] {sym2} base) val mem) && is32Bit(int64(off1)+int64(off2)) && canMergeSym(sym1, sym2) =>
   293	(MOVDstore [off1+off2] {mergeSym(sym1,sym2)} base val mem)
   294(MOVBstorezero [off1] {sym1} (MOVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
   295	(MOVBstorezero [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
   296(MOVHstorezero [off1] {sym1} (MOVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
   297	(MOVHstorezero [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
   298(MOVWstorezero [off1] {sym1} (MOVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
   299	(MOVWstorezero [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
   300(MOVDstorezero [off1] {sym1} (MOVaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) && is32Bit(int64(off1)+int64(off2)) =>
   301	(MOVDstorezero [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
   302
   303(MOVBUload [off1] {sym} (ADDI [off2] base) mem) && is32Bit(int64(off1)+off2) =>
   304	(MOVBUload [off1+int32(off2)] {sym} base mem)
   305(MOVBload  [off1] {sym} (ADDI [off2] base) mem) && is32Bit(int64(off1)+off2) =>
   306	(MOVBload  [off1+int32(off2)] {sym} base mem)
   307(MOVHUload [off1] {sym} (ADDI [off2] base) mem) && is32Bit(int64(off1)+off2) =>
   308	(MOVHUload [off1+int32(off2)] {sym} base mem)
   309(MOVHload  [off1] {sym} (ADDI [off2] base) mem) && is32Bit(int64(off1)+off2) =>
   310	(MOVHload  [off1+int32(off2)] {sym} base mem)
   311(MOVWUload [off1] {sym} (ADDI [off2] base) mem) && is32Bit(int64(off1)+off2) =>
   312	(MOVWUload [off1+int32(off2)] {sym} base mem)
   313(MOVWload  [off1] {sym} (ADDI [off2] base) mem) && is32Bit(int64(off1)+off2) =>
   314	(MOVWload  [off1+int32(off2)] {sym} base mem)
   315(MOVDload  [off1] {sym} (ADDI [off2] base) mem) && is32Bit(int64(off1)+off2) =>
   316	(MOVDload  [off1+int32(off2)] {sym} base mem)
   317
   318(MOVBstore [off1] {sym} (ADDI [off2] base) val mem) && is32Bit(int64(off1)+off2) =>
   319	(MOVBstore [off1+int32(off2)] {sym} base val mem)
   320(MOVHstore [off1] {sym} (ADDI [off2] base) val mem) && is32Bit(int64(off1)+off2) =>
   321	(MOVHstore [off1+int32(off2)] {sym} base val mem)
   322(MOVWstore [off1] {sym} (ADDI [off2] base) val mem) && is32Bit(int64(off1)+off2) =>
   323	(MOVWstore [off1+int32(off2)] {sym} base val mem)
   324(MOVDstore [off1] {sym} (ADDI [off2] base) val mem) && is32Bit(int64(off1)+off2) =>
   325	(MOVDstore [off1+int32(off2)] {sym} base val mem)
   326(MOVBstorezero [off1] {sym} (ADDI [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVBstorezero [off1+int32(off2)] {sym} ptr mem)
   327(MOVHstorezero [off1] {sym} (ADDI [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVHstorezero [off1+int32(off2)] {sym} ptr mem)
   328(MOVWstorezero [off1] {sym} (ADDI [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVWstorezero [off1+int32(off2)] {sym} ptr mem)
   329(MOVDstorezero [off1] {sym} (ADDI [off2] ptr) mem) && is32Bit(int64(off1)+off2) => (MOVDstorezero [off1+int32(off2)] {sym} ptr mem)
   330
   331// Similarly, fold ADDI into MOVaddr to avoid confusing live variable analysis
   332// with OffPtr -> ADDI.
   333(ADDI [c] (MOVaddr [d] {s} x)) && is32Bit(c+int64(d)) => (MOVaddr [int32(c)+d] {s} x)
   334
   335// Small zeroing
   336(Zero [0] _ mem) => mem
   337(Zero [1] ptr mem) => (MOVBstore ptr (MOVDconst [0]) mem)
   338(Zero [2] {t} ptr mem) && t.Alignment()%2 == 0 =>
   339	(MOVHstore ptr (MOVDconst [0]) mem)
   340(Zero [2] ptr mem) =>
   341	(MOVBstore [1] ptr (MOVDconst [0])
   342		(MOVBstore ptr (MOVDconst [0]) mem))
   343(Zero [4] {t} ptr mem) && t.Alignment()%4 == 0 =>
   344	(MOVWstore ptr (MOVDconst [0]) mem)
   345(Zero [4] {t} ptr mem) && t.Alignment()%2 == 0 =>
   346	(MOVHstore [2] ptr (MOVDconst [0])
   347		(MOVHstore ptr (MOVDconst [0]) mem))
   348(Zero [4] ptr mem) =>
   349	(MOVBstore [3] ptr (MOVDconst [0])
   350		(MOVBstore [2] ptr (MOVDconst [0])
   351			(MOVBstore [1] ptr (MOVDconst [0])
   352				(MOVBstore ptr (MOVDconst [0]) mem))))
   353(Zero [8] {t} ptr mem) && t.Alignment()%8 == 0 =>
   354	(MOVDstore ptr (MOVDconst [0]) mem)
   355(Zero [8] {t} ptr mem) && t.Alignment()%4 == 0 =>
   356	(MOVWstore [4] ptr (MOVDconst [0])
   357		(MOVWstore ptr (MOVDconst [0]) mem))
   358(Zero [8] {t} ptr mem) && t.Alignment()%2 == 0 =>
   359	(MOVHstore [6] ptr (MOVDconst [0])
   360		(MOVHstore [4] ptr (MOVDconst [0])
   361			(MOVHstore [2] ptr (MOVDconst [0])
   362				(MOVHstore ptr (MOVDconst [0]) mem))))
   363
   364(Zero [3] ptr mem) =>
   365	(MOVBstore [2] ptr (MOVDconst [0])
   366		(MOVBstore [1] ptr (MOVDconst [0])
   367			(MOVBstore ptr (MOVDconst [0]) mem)))
   368(Zero [6] {t} ptr mem) && t.Alignment()%2 == 0 =>
   369	(MOVHstore [4] ptr (MOVDconst [0])
   370		(MOVHstore [2] ptr (MOVDconst [0])
   371			(MOVHstore ptr (MOVDconst [0]) mem)))
   372(Zero [12] {t} ptr mem) && t.Alignment()%4 == 0 =>
   373	(MOVWstore [8] ptr (MOVDconst [0])
   374		(MOVWstore [4] ptr (MOVDconst [0])
   375			(MOVWstore ptr (MOVDconst [0]) mem)))
   376(Zero [16] {t} ptr mem) && t.Alignment()%8 == 0 =>
   377	(MOVDstore [8] ptr (MOVDconst [0])
   378		(MOVDstore ptr (MOVDconst [0]) mem))
   379(Zero [24] {t} ptr mem) && t.Alignment()%8 == 0 =>
   380	(MOVDstore [16] ptr (MOVDconst [0])
   381		(MOVDstore [8] ptr (MOVDconst [0])
   382			(MOVDstore ptr (MOVDconst [0]) mem)))
   383(Zero [32] {t} ptr mem) && t.Alignment()%8 == 0 =>
   384	(MOVDstore [24] ptr (MOVDconst [0])
   385		(MOVDstore [16] ptr (MOVDconst [0])
   386			(MOVDstore [8] ptr (MOVDconst [0])
   387				(MOVDstore ptr (MOVDconst [0]) mem))))
   388
   389// Medium 8-aligned zeroing uses a Duff's device
   390// 8 and 128 are magic constants, see runtime/mkduff.go
   391(Zero [s] {t} ptr mem)
   392	&& s%8 == 0 && s <= 8*128
   393	&& t.Alignment()%8 == 0 && !config.noDuffDevice =>
   394	(DUFFZERO [8 * (128 - s/8)] ptr mem)
   395
   396// Generic zeroing uses a loop
   397(Zero [s] {t} ptr mem) =>
   398	(LoweredZero [t.Alignment()]
   399		ptr
   400		(ADD <ptr.Type> ptr (MOVDconst [s-moveSize(t.Alignment(), config)]))
   401		mem)
   402
   403// Checks
   404(IsNonNil ...) => (SNEZ ...)
   405(IsInBounds ...) => (Less64U ...)
   406(IsSliceInBounds ...) => (Leq64U ...)
   407
   408// Trivial lowering
   409(NilCheck ...) => (LoweredNilCheck ...)
   410(GetClosurePtr ...) => (LoweredGetClosurePtr ...)
   411(GetCallerSP ...) => (LoweredGetCallerSP ...)
   412(GetCallerPC ...) => (LoweredGetCallerPC ...)
   413
   414// Write barrier.
   415(WB ...) => (LoweredWB ...)
   416
   417// Publication barrier as intrinsic
   418(PubBarrier ...) => (LoweredPubBarrier ...)
   419
   420(PanicBounds [kind] x y mem) && boundsABI(kind) == 0 => (LoweredPanicBoundsA [kind] x y mem)
   421(PanicBounds [kind] x y mem) && boundsABI(kind) == 1 => (LoweredPanicBoundsB [kind] x y mem)
   422(PanicBounds [kind] x y mem) && boundsABI(kind) == 2 => (LoweredPanicBoundsC [kind] x y mem)
   423
   424// Small moves
   425(Move [0] _ _ mem) => mem
   426(Move [1] dst src mem) => (MOVBstore dst (MOVBload src mem) mem)
   427(Move [2] {t} dst src mem) && t.Alignment()%2 == 0 =>
   428	(MOVHstore dst (MOVHload src mem) mem)
   429(Move [2] dst src mem) =>
   430	(MOVBstore [1] dst (MOVBload [1] src mem)
   431		(MOVBstore dst (MOVBload src mem) mem))
   432(Move [4] {t} dst src mem) && t.Alignment()%4 == 0 =>
   433	(MOVWstore dst (MOVWload src mem) mem)
   434(Move [4] {t} dst src mem) && t.Alignment()%2 == 0 =>
   435	(MOVHstore [2] dst (MOVHload [2] src mem)
   436		(MOVHstore dst (MOVHload src mem) mem))
   437(Move [4] dst src mem) =>
   438	(MOVBstore [3] dst (MOVBload [3] src mem)
   439		(MOVBstore [2] dst (MOVBload [2] src mem)
   440			(MOVBstore [1] dst (MOVBload [1] src mem)
   441				(MOVBstore dst (MOVBload src mem) mem))))
   442(Move [8] {t} dst src mem) && t.Alignment()%8 == 0 =>
   443	(MOVDstore dst (MOVDload src mem) mem)
   444(Move [8] {t} dst src mem) && t.Alignment()%4 == 0 =>
   445	(MOVWstore [4] dst (MOVWload [4] src mem)
   446		(MOVWstore dst (MOVWload src mem) mem))
   447(Move [8] {t} dst src mem) && t.Alignment()%2 == 0 =>
   448	(MOVHstore [6] dst (MOVHload [6] src mem)
   449		(MOVHstore [4] dst (MOVHload [4] src mem)
   450			(MOVHstore [2] dst (MOVHload [2] src mem)
   451				(MOVHstore dst (MOVHload src mem) mem))))
   452
   453(Move [3] dst src mem) =>
   454	(MOVBstore [2] dst (MOVBload [2] src mem)
   455		(MOVBstore [1] dst (MOVBload [1] src mem)
   456			(MOVBstore dst (MOVBload src mem) mem)))
   457(Move [6] {t} dst src mem) && t.Alignment()%2 == 0 =>
   458	(MOVHstore [4] dst (MOVHload [4] src mem)
   459		(MOVHstore [2] dst (MOVHload [2] src mem)
   460			(MOVHstore dst (MOVHload src mem) mem)))
   461(Move [12] {t} dst src mem) && t.Alignment()%4 == 0 =>
   462	(MOVWstore [8] dst (MOVWload [8] src mem)
   463		(MOVWstore [4] dst (MOVWload [4] src mem)
   464			(MOVWstore dst (MOVWload src mem) mem)))
   465(Move [16] {t} dst src mem) && t.Alignment()%8 == 0 =>
   466	(MOVDstore [8] dst (MOVDload [8] src mem)
   467		(MOVDstore dst (MOVDload src mem) mem))
   468(Move [24] {t} dst src mem) && t.Alignment()%8 == 0 =>
   469	(MOVDstore [16] dst (MOVDload [16] src mem)
   470		(MOVDstore [8] dst (MOVDload [8] src mem)
   471			(MOVDstore dst (MOVDload src mem) mem)))
   472(Move [32] {t} dst src mem) && t.Alignment()%8 == 0 =>
   473	(MOVDstore [24] dst (MOVDload [24] src mem)
   474		(MOVDstore [16] dst (MOVDload [16] src mem)
   475			(MOVDstore [8] dst (MOVDload [8] src mem)
   476				(MOVDstore dst (MOVDload src mem) mem))))
   477
   478// Medium 8-aligned move uses a Duff's device
   479// 16 and 128 are magic constants, see runtime/mkduff.go
   480(Move [s] {t} dst src mem)
   481	&& s%8 == 0 && s <= 8*128 && t.Alignment()%8 == 0
   482	&& !config.noDuffDevice && logLargeCopy(v, s) =>
   483	(DUFFCOPY [16 * (128 - s/8)] dst src mem)
   484
   485// Generic move uses a loop
   486(Move [s] {t} dst src mem) && (s <= 16 || logLargeCopy(v, s)) =>
   487	(LoweredMove [t.Alignment()]
   488		dst
   489		src
   490		(ADDI <src.Type> [s-moveSize(t.Alignment(), config)] src)
   491		mem)
   492
   493// Boolean ops; 0=false, 1=true
   494(AndB ...) => (AND ...)
   495(OrB  ...) => (OR  ...)
   496(EqB  x y) => (SEQZ (SUB <typ.Bool> x y))
   497(NeqB x y) => (SNEZ (SUB <typ.Bool> x y))
   498(Not  ...) => (SEQZ ...)
   499
   500// Lowering pointer arithmetic
   501// TODO: Special handling for SP offsets, like ARM
   502(OffPtr [off] ptr:(SP)) && is32Bit(off) => (MOVaddr [int32(off)] ptr)
   503(OffPtr [off] ptr) && is32Bit(off) => (ADDI [off] ptr)
   504(OffPtr [off] ptr) => (ADD (MOVDconst [off]) ptr)
   505
   506(Const(64|32|16|8) [val]) => (MOVDconst [int64(val)])
   507(Const32F [val]) => (FMVSX (MOVDconst [int64(math.Float32bits(val))]))
   508(Const64F [val]) => (FMVDX (MOVDconst [int64(math.Float64bits(val))]))
   509(ConstNil) => (MOVDconst [0])
   510(ConstBool [val]) => (MOVDconst [int64(b2i(val))])
   511
   512(Addr {sym} base) => (MOVaddr {sym} [0] base)
   513(LocalAddr <t> {sym} base mem) && t.Elem().HasPointers() => (MOVaddr {sym} (SPanchored base mem))
   514(LocalAddr <t> {sym} base _)  && !t.Elem().HasPointers() => (MOVaddr {sym} base)
   515
   516// Calls
   517(StaticCall  ...) => (CALLstatic  ...)
   518(ClosureCall ...) => (CALLclosure ...)
   519(InterCall   ...) => (CALLinter   ...)
   520(TailCall ...) => (CALLtail ...)
   521
   522// Atomic Intrinsics
   523(AtomicLoad(Ptr|64|32|8)  ...) => (LoweredAtomicLoad(64|64|32|8) ...)
   524(AtomicStore(PtrNoWB|64|32|8) ...) => (LoweredAtomicStore(64|64|32|8) ...)
   525(AtomicAdd(64|32) ...) => (LoweredAtomicAdd(64|32) ...)
   526
   527// AtomicAnd8(ptr,val) => LoweredAtomicAnd32(ptr&^3, ^((uint8(val) ^ 0xff) << ((ptr & 3) * 8)))
   528(AtomicAnd8 ptr val mem) =>
   529	(LoweredAtomicAnd32 (ANDI <typ.Uintptr> [^3] ptr)
   530		(NOT <typ.UInt32> (SLL <typ.UInt32> (XORI <typ.UInt32> [0xff] (ZeroExt8to32 val))
   531			(SLLI <typ.UInt64> [3] (ANDI <typ.UInt64> [3] ptr)))) mem)
   532
   533(AtomicAnd32 ...) => (LoweredAtomicAnd32 ...)
   534
   535(AtomicCompareAndSwap32 ptr old new mem) => (LoweredAtomicCas32 ptr (SignExt32to64 old) new mem)
   536(AtomicCompareAndSwap64 ...) => (LoweredAtomicCas64 ...)
   537
   538(AtomicExchange(64|32) ...) => (LoweredAtomicExchange(64|32) ...)
   539
   540// AtomicOr8(ptr,val)  => LoweredAtomicOr32(ptr&^3, uint32(val)<<((ptr&3)*8))
   541(AtomicOr8 ptr val mem) =>
   542	(LoweredAtomicOr32 (ANDI <typ.Uintptr> [^3] ptr)
   543		(SLL <typ.UInt32> (ZeroExt8to32 val)
   544			(SLLI <typ.UInt64> [3] (ANDI <typ.UInt64> [3] ptr))) mem)
   545
   546(AtomicOr32  ...) => (LoweredAtomicOr32  ...)
   547
   548// Conditional branches
   549(If cond yes no) => (BNEZ (MOVBUreg <typ.UInt64> cond) yes no)
   550
   551// Optimizations
   552
   553// Absorb SEQZ/SNEZ into branch.
   554(BEQZ (SEQZ x) yes no) => (BNEZ x yes no)
   555(BEQZ (SNEZ x) yes no) => (BEQZ x yes no)
   556(BNEZ (SEQZ x) yes no) => (BEQZ x yes no)
   557(BNEZ (SNEZ x) yes no) => (BNEZ x yes no)
   558
   559// Remove redundant NEG from BEQZ/BNEZ.
   560(BEQZ (NEG x) yes no) => (BEQZ x yes no)
   561(BNEZ (NEG x) yes no) => (BNEZ x yes no)
   562
   563// Negate comparison with FNES/FNED.
   564(BEQZ (FNES <t> x y) yes no) => (BNEZ (FEQS <t> x y) yes no)
   565(BNEZ (FNES <t> x y) yes no) => (BEQZ (FEQS <t> x y) yes no)
   566(BEQZ (FNED <t> x y) yes no) => (BNEZ (FEQD <t> x y) yes no)
   567(BNEZ (FNED <t> x y) yes no) => (BEQZ (FEQD <t> x y) yes no)
   568
   569// Convert BEQZ/BNEZ into more optimal branch conditions.
   570(BEQZ (SUB x y) yes no) => (BEQ x y yes no)
   571(BNEZ (SUB x y) yes no) => (BNE x y yes no)
   572(BEQZ (SLT x y) yes no) => (BGE x y yes no)
   573(BNEZ (SLT x y) yes no) => (BLT x y yes no)
   574(BEQZ (SLTU x y) yes no) => (BGEU x y yes no)
   575(BNEZ (SLTU x y) yes no) => (BLTU x y yes no)
   576(BEQZ (SLTI [x] y) yes no) => (BGE y (MOVDconst [x]) yes no)
   577(BNEZ (SLTI [x] y) yes no) => (BLT y (MOVDconst [x]) yes no)
   578(BEQZ (SLTIU [x] y) yes no) => (BGEU y (MOVDconst [x]) yes no)
   579(BNEZ (SLTIU [x] y) yes no) => (BLTU y (MOVDconst [x]) yes no)
   580
   581// Convert branch with zero to more optimal branch zero.
   582(BEQ (MOVDconst [0]) cond yes no) => (BEQZ cond yes no)
   583(BEQ cond (MOVDconst [0]) yes no) => (BEQZ cond yes no)
   584(BNE (MOVDconst [0]) cond yes no) => (BNEZ cond yes no)
   585(BNE cond (MOVDconst [0]) yes no) => (BNEZ cond yes no)
   586(BLT (MOVDconst [0]) cond yes no) => (BGTZ cond yes no)
   587(BLT cond (MOVDconst [0]) yes no) => (BLTZ cond yes no)
   588(BGE (MOVDconst [0]) cond yes no) => (BLEZ cond yes no)
   589(BGE cond (MOVDconst [0]) yes no) => (BGEZ cond yes no)
   590
   591// Remove redundant NEG from SEQZ/SNEZ.
   592(SEQZ (NEG x)) => (SEQZ x)
   593(SNEZ (NEG x)) => (SNEZ x)
   594
   595// Remove redundant SEQZ/SNEZ.
   596(SEQZ (SEQZ x)) => (SNEZ x)
   597(SEQZ (SNEZ x)) => (SEQZ x)
   598(SNEZ (SEQZ x)) => (SEQZ x)
   599(SNEZ (SNEZ x)) => (SNEZ x)
   600
   601// Store zero.
   602(MOVBstore [off] {sym} ptr (MOVDconst [0]) mem) => (MOVBstorezero [off] {sym} ptr mem)
   603(MOVHstore [off] {sym} ptr (MOVDconst [0]) mem) => (MOVHstorezero [off] {sym} ptr mem)
   604(MOVWstore [off] {sym} ptr (MOVDconst [0]) mem) => (MOVWstorezero [off] {sym} ptr mem)
   605(MOVDstore [off] {sym} ptr (MOVDconst [0]) mem) => (MOVDstorezero [off] {sym} ptr mem)
   606
   607// Boolean ops are already extended.
   608(MOVBUreg x:((FLES|FLTS|FEQS|FNES) _ _)) => x
   609(MOVBUreg x:((FLED|FLTD|FEQD|FNED) _ _)) => x
   610(MOVBUreg x:((SEQZ|SNEZ) _)) => x
   611(MOVBUreg x:((SLT|SLTU) _ _)) => x
   612
   613// Avoid extending when already sufficiently masked.
   614(MOVBreg  x:(ANDI [c] y)) && c >= 0 && int64(int8(c)) == c => x
   615(MOVHreg  x:(ANDI [c] y)) && c >= 0 && int64(int16(c)) == c => x
   616(MOVWreg  x:(ANDI [c] y)) && c >= 0 && int64(int32(c)) == c => x
   617(MOVBUreg x:(ANDI [c] y)) && c >= 0 && int64(uint8(c)) == c => x
   618(MOVHUreg x:(ANDI [c] y)) && c >= 0 && int64(uint16(c)) == c => x
   619(MOVWUreg x:(ANDI [c] y)) && c >= 0 && int64(uint32(c)) == c => x
   620
   621// Combine masking and zero extension.
   622(MOVBUreg (ANDI [c] x)) && c < 0 => (ANDI [int64(uint8(c))] x)
   623(MOVHUreg (ANDI [c] x)) && c < 0 => (ANDI [int64(uint16(c))] x)
   624(MOVWUreg (ANDI [c] x)) && c < 0 => (AND (MOVDconst [int64(uint32(c))]) x)
   625
   626// Avoid sign/zero extension for consts.
   627(MOVBreg  (MOVDconst [c])) => (MOVDconst [int64(int8(c))])
   628(MOVHreg  (MOVDconst [c])) => (MOVDconst [int64(int16(c))])
   629(MOVWreg  (MOVDconst [c])) => (MOVDconst [int64(int32(c))])
   630(MOVBUreg (MOVDconst [c])) => (MOVDconst [int64(uint8(c))])
   631(MOVHUreg (MOVDconst [c])) => (MOVDconst [int64(uint16(c))])
   632(MOVWUreg (MOVDconst [c])) => (MOVDconst [int64(uint32(c))])
   633
   634// Avoid sign/zero extension after properly typed load.
   635(MOVBreg  x:(MOVBload  _ _)) => (MOVDreg x)
   636(MOVHreg  x:(MOVBload  _ _)) => (MOVDreg x)
   637(MOVHreg  x:(MOVBUload _ _)) => (MOVDreg x)
   638(MOVHreg  x:(MOVHload  _ _)) => (MOVDreg x)
   639(MOVWreg  x:(MOVBload  _ _)) => (MOVDreg x)
   640(MOVWreg  x:(MOVBUload _ _)) => (MOVDreg x)
   641(MOVWreg  x:(MOVHload  _ _)) => (MOVDreg x)
   642(MOVWreg  x:(MOVHUload _ _)) => (MOVDreg x)
   643(MOVWreg  x:(MOVWload  _ _)) => (MOVDreg x)
   644(MOVBUreg x:(MOVBUload _ _)) => (MOVDreg x)
   645(MOVHUreg x:(MOVBUload _ _)) => (MOVDreg x)
   646(MOVHUreg x:(MOVHUload _ _)) => (MOVDreg x)
   647(MOVWUreg x:(MOVBUload _ _)) => (MOVDreg x)
   648(MOVWUreg x:(MOVHUload _ _)) => (MOVDreg x)
   649(MOVWUreg x:(MOVWUload _ _)) => (MOVDreg x)
   650
   651// Avoid zero extension after properly typed atomic operation.
   652(MOVBUreg x:(Select0 (LoweredAtomicLoad8 _ _))) => (MOVDreg x)
   653(MOVBUreg x:(Select0 (LoweredAtomicCas32 _ _ _ _))) => (MOVDreg x)
   654(MOVBUreg x:(Select0 (LoweredAtomicCas64 _ _ _ _))) => (MOVDreg x)
   655
   656// Avoid sign extension after word arithmetic.
   657(MOVWreg x:(ADDIW   _)) => (MOVDreg x)
   658(MOVWreg x:(SUBW  _ _)) => (MOVDreg x)
   659(MOVWreg x:(NEGW    _)) => (MOVDreg x)
   660(MOVWreg x:(MULW  _ _)) => (MOVDreg x)
   661(MOVWreg x:(DIVW  _ _)) => (MOVDreg x)
   662(MOVWreg x:(DIVUW _ _)) => (MOVDreg x)
   663(MOVWreg x:(REMW  _ _)) => (MOVDreg x)
   664(MOVWreg x:(REMUW _ _)) => (MOVDreg x)
   665
   666// Fold double extensions.
   667(MOVBreg  x:(MOVBreg  _)) => (MOVDreg x)
   668(MOVHreg  x:(MOVBreg  _)) => (MOVDreg x)
   669(MOVHreg  x:(MOVBUreg _)) => (MOVDreg x)
   670(MOVHreg  x:(MOVHreg  _)) => (MOVDreg x)
   671(MOVWreg  x:(MOVBreg  _)) => (MOVDreg x)
   672(MOVWreg  x:(MOVBUreg _)) => (MOVDreg x)
   673(MOVWreg  x:(MOVHreg  _)) => (MOVDreg x)
   674(MOVWreg  x:(MOVWreg  _)) => (MOVDreg x)
   675(MOVBUreg x:(MOVBUreg _)) => (MOVDreg x)
   676(MOVHUreg x:(MOVBUreg _)) => (MOVDreg x)
   677(MOVHUreg x:(MOVHUreg _)) => (MOVDreg x)
   678(MOVWUreg x:(MOVBUreg _)) => (MOVDreg x)
   679(MOVWUreg x:(MOVHUreg _)) => (MOVDreg x)
   680(MOVWUreg x:(MOVWUreg _)) => (MOVDreg x)
   681
   682// Do not extend before store.
   683(MOVBstore [off] {sym} ptr (MOVBreg  x) mem) => (MOVBstore [off] {sym} ptr x mem)
   684(MOVBstore [off] {sym} ptr (MOVHreg  x) mem) => (MOVBstore [off] {sym} ptr x mem)
   685(MOVBstore [off] {sym} ptr (MOVWreg  x) mem) => (MOVBstore [off] {sym} ptr x mem)
   686(MOVBstore [off] {sym} ptr (MOVBUreg x) mem) => (MOVBstore [off] {sym} ptr x mem)
   687(MOVBstore [off] {sym} ptr (MOVHUreg x) mem) => (MOVBstore [off] {sym} ptr x mem)
   688(MOVBstore [off] {sym} ptr (MOVWUreg x) mem) => (MOVBstore [off] {sym} ptr x mem)
   689(MOVHstore [off] {sym} ptr (MOVHreg  x) mem) => (MOVHstore [off] {sym} ptr x mem)
   690(MOVHstore [off] {sym} ptr (MOVWreg  x) mem) => (MOVHstore [off] {sym} ptr x mem)
   691(MOVHstore [off] {sym} ptr (MOVHUreg x) mem) => (MOVHstore [off] {sym} ptr x mem)
   692(MOVHstore [off] {sym} ptr (MOVWUreg x) mem) => (MOVHstore [off] {sym} ptr x mem)
   693(MOVWstore [off] {sym} ptr (MOVWreg  x) mem) => (MOVWstore [off] {sym} ptr x mem)
   694(MOVWstore [off] {sym} ptr (MOVWUreg x) mem) => (MOVWstore [off] {sym} ptr x mem)
   695
   696// Replace extend after load with alternate load where possible.
   697(MOVBreg  <t> x:(MOVBUload [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) => @x.Block (MOVBload  <t> [off] {sym} ptr mem)
   698(MOVHreg  <t> x:(MOVHUload [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) => @x.Block (MOVHload  <t> [off] {sym} ptr mem)
   699(MOVWreg  <t> x:(MOVWUload [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) => @x.Block (MOVWload  <t> [off] {sym} ptr mem)
   700(MOVBUreg <t> x:(MOVBload  [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) => @x.Block (MOVBUload <t> [off] {sym} ptr mem)
   701(MOVHUreg <t> x:(MOVHload  [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) => @x.Block (MOVHUload <t> [off] {sym} ptr mem)
   702(MOVWUreg <t> x:(MOVWload  [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) => @x.Block (MOVWUload <t> [off] {sym} ptr mem)
   703
   704// If a register move has only 1 use, just use the same register without emitting instruction
   705// MOVnop does not emit an instruction, only for ensuring the type.
   706(MOVDreg x) && x.Uses == 1 => (MOVDnop x)
   707
   708// TODO: we should be able to get rid of MOVDnop all together.
   709// But for now, this is enough to get rid of lots of them.
   710(MOVDnop (MOVDconst [c])) => (MOVDconst [c])
   711
   712// Avoid unnecessary zero and sign extension when right shifting.
   713(SRAI <t> [x] (MOVWreg  y)) && x >= 0 && x <= 31 => (SRAIW <t> [int64(x)] y)
   714(SRLI <t> [x] (MOVWUreg y)) && x >= 0 && x <= 31 => (SRLIW <t> [int64(x)] y)
   715
   716// Replace right shifts that exceed size of signed type.
   717(SRAI <t> [x] (MOVBreg y)) && x >=  8 => (SRAI  [63] (SLLI <t> [56] y))
   718(SRAI <t> [x] (MOVHreg y)) && x >= 16 => (SRAI  [63] (SLLI <t> [48] y))
   719(SRAI <t> [x] (MOVWreg y)) && x >= 32 => (SRAIW [31] y)
   720
   721// Eliminate right shifts that exceed size of unsigned type.
   722(SRLI <t> [x] (MOVBUreg y)) && x >=  8 => (MOVDconst <t> [0])
   723(SRLI <t> [x] (MOVHUreg y)) && x >= 16 => (MOVDconst <t> [0])
   724(SRLI <t> [x] (MOVWUreg y)) && x >= 32 => (MOVDconst <t> [0])
   725
   726// Fold constant into immediate instructions where possible.
   727(ADD (MOVDconst <t> [val]) x) && is32Bit(val) && !t.IsPtr() => (ADDI [val] x)
   728(AND (MOVDconst [val]) x) && is32Bit(val) => (ANDI [val] x)
   729(OR  (MOVDconst [val]) x) && is32Bit(val) => (ORI  [val] x)
   730(XOR (MOVDconst [val]) x) && is32Bit(val) => (XORI [val] x)
   731(SLL  x (MOVDconst [val])) => (SLLI [int64(val&63)] x)
   732(SRL  x (MOVDconst [val])) => (SRLI [int64(val&63)] x)
   733(SRLW x (MOVDconst [val])) => (SRLIW [int64(val&31)] x)
   734(SRA  x (MOVDconst [val])) => (SRAI [int64(val&63)] x)
   735(SRAW x (MOVDconst [val])) => (SRAIW [int64(val&31)] x)
   736(SLT  x (MOVDconst [val])) && val >= -2048 && val <= 2047 => (SLTI  [val] x)
   737(SLTU x (MOVDconst [val])) && val >= -2048 && val <= 2047 => (SLTIU [val] x)
   738
   739// Convert const subtraction into ADDI with negative immediate, where possible.
   740(SUB x (MOVDconst [val])) && is32Bit(-val) => (ADDI [-val] x)
   741(SUB <t> (MOVDconst [val]) y) && is32Bit(-val) => (NEG (ADDI <t> [-val] y))
   742
   743// Subtraction of zero.
   744(SUB  x (MOVDconst [0])) => x
   745(SUBW x (MOVDconst [0])) => (ADDIW [0] x)
   746
   747// Subtraction from zero.
   748(SUB  (MOVDconst [0]) x) => (NEG x)
   749(SUBW (MOVDconst [0]) x) => (NEGW x)
   750
   751// Fold negation into subtraction.
   752(NEG (SUB x y)) => (SUB y x)
   753(NEG <t> s:(ADDI [val] (SUB x y))) && s.Uses == 1 && is32Bit(-val) => (ADDI [-val] (SUB <t> y x))
   754
   755// Double negation.
   756(NEG (NEG x)) => x
   757
   758// Addition of zero or two constants.
   759(ADDI [0] x) => x
   760(ADDI [x] (MOVDconst [y])) && is32Bit(x + y) => (MOVDconst [x + y])
   761
   762// ANDI with all zeros, all ones or two constants.
   763(ANDI [0]  x) => (MOVDconst [0])
   764(ANDI [-1] x) => x
   765(ANDI [x] (MOVDconst [y])) => (MOVDconst [x & y])
   766
   767// ORI with all zeroes, all ones or two constants.
   768(ORI [0]  x) => x
   769(ORI [-1] x) => (MOVDconst [-1])
   770(ORI [x] (MOVDconst [y])) => (MOVDconst [x | y])
   771
   772// Combine operations with immediate.
   773(ADDI [x] (ADDI [y] z)) && is32Bit(x + y) => (ADDI [x + y] z)
   774(ANDI [x] (ANDI [y] z)) => (ANDI [x & y] z)
   775(ORI  [x] (ORI  [y] z)) => (ORI  [x | y] z)
   776
   777// Negation of a constant.
   778(NEG  (MOVDconst [x])) => (MOVDconst [-x])
   779(NEGW (MOVDconst [x])) => (MOVDconst [int64(int32(-x))])
   780
   781// Shift of a constant.
   782(SLLI [x] (MOVDconst [y])) && is32Bit(y << uint32(x)) => (MOVDconst [y << uint32(x)])
   783(SRLI [x] (MOVDconst [y])) => (MOVDconst [int64(uint64(y) >> uint32(x))])
   784(SRAI [x] (MOVDconst [y])) => (MOVDconst [int64(y) >> uint32(x)])
   785
   786// SLTI/SLTIU with constants.
   787(SLTI  [x] (MOVDconst [y])) => (MOVDconst [b2i(int64(y) < int64(x))])
   788(SLTIU [x] (MOVDconst [y])) => (MOVDconst [b2i(uint64(y) < uint64(x))])
   789
   790// SLTI/SLTIU with known outcomes.
   791(SLTI  [x] (ANDI [y] _)) && y >= 0 && int64(y) < int64(x) => (MOVDconst [1])
   792(SLTIU [x] (ANDI [y] _)) && y >= 0 && uint64(y) < uint64(x) => (MOVDconst [1])
   793(SLTI  [x] (ORI  [y] _)) && y >= 0 && int64(y) >= int64(x) => (MOVDconst [0])
   794(SLTIU [x] (ORI  [y] _)) && y >= 0 && uint64(y) >= uint64(x) => (MOVDconst [0])
   795
   796// SLT/SLTU with known outcomes.
   797(SLT  x x) => (MOVDconst [0])
   798(SLTU x x) => (MOVDconst [0])
   799
   800// Deadcode for LoweredMuluhilo
   801(Select0 m:(LoweredMuluhilo x y)) && m.Uses == 1 => (MULHU x y)
   802(Select1 m:(LoweredMuluhilo x y)) && m.Uses == 1 => (MUL x y)
   803
   804(FADD(S|D) a (FMUL(S|D) x y)) && a.Block.Func.useFMA(v) => (FMADD(S|D) x y a)
   805(FSUB(S|D) a (FMUL(S|D) x y)) && a.Block.Func.useFMA(v) => (FNMSUB(S|D) x y a)
   806(FSUB(S|D) (FMUL(S|D) x y) a) && a.Block.Func.useFMA(v) => (FMSUB(S|D) x y a)
   807
   808// Merge negation into fused multiply-add and multiply-subtract.
   809//
   810// Key:
   811//
   812//   [+ -](x * y [+ -] z).
   813//    _ N         A S
   814//                D U
   815//                D B
   816//
   817// Note: multiplication commutativity handled by rule generator.
   818(F(MADD|NMADD|MSUB|NMSUB)S neg:(FNEGS x) y z) && neg.Uses == 1 => (F(NMSUB|MSUB|NMADD|MADD)S x y z)
   819(F(MADD|NMADD|MSUB|NMSUB)S x y neg:(FNEGS z)) && neg.Uses == 1 => (F(MSUB|NMSUB|MADD|NMADD)S x y z)
   820(F(MADD|NMADD|MSUB|NMSUB)D neg:(FNEGD x) y z) && neg.Uses == 1 => (F(NMSUB|MSUB|NMADD|MADD)D x y z)
   821(F(MADD|NMADD|MSUB|NMSUB)D x y neg:(FNEGD z)) && neg.Uses == 1 => (F(MSUB|NMSUB|MADD|NMADD)D x y z)

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