path: root/src/cmd/compile/internal/ssa/gen/386.rules

// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Lowering arithmetic
(Add(Ptr|32|16|8) x y) -> (ADDL  x y)
(Add(32|64)F x y) -> (ADDS(S|D) x y)
(Add32carry x y) -> (ADDLcarry x y)
(Add32withcarry x y c) -> (ADCL x y c)

(Sub(Ptr|32|16|8) x y) -> (SUBL  x y)
(Sub(32|64)F x y) -> (SUBS(S|D) x y)
(Sub32carry x y) -> (SUBLcarry x y)
(Sub32withcarry x y c) -> (SBBL x y c)

(Mul(32|16|8)  x y) -> (MULL  x y)
(Mul(32|64)F x y) -> (MULS(S|D) x y)
(Mul32uhilo x y) -> (MULLQU x y)

(Avg32u x y) -> (AVGLU x y)

(Div32F x y) -> (DIVSS x y)
(Div64F x y) -> (DIVSD x y)

(Div32  x y) -> (DIVL  x y)
(Div32u x y) -> (DIVLU x y)
(Div16  x y) -> (DIVW  x y)
(Div16u x y) -> (DIVWU x y)
(Div8   x y) -> (DIVW  (SignExt8to16 x) (SignExt8to16 y))
(Div8u  x y) -> (DIVWU (ZeroExt8to16 x) (ZeroExt8to16 y))

(Hmul32  x y) -> (HMULL  x y)
(Hmul32u x y) -> (HMULLU x y)

(Mod32  x y) -> (MODL  x y)
(Mod32u x y) -> (MODLU x y)
(Mod16  x y) -> (MODW  x y)
(Mod16u x y) -> (MODWU x y)
(Mod8   x y) -> (MODW  (SignExt8to16 x) (SignExt8to16 y))
(Mod8u  x y) -> (MODWU (ZeroExt8to16 x) (ZeroExt8to16 y))

(And(32|16|8) x y) -> (ANDL x y)
(Or(32|16|8) x y) -> (ORL x y)
(Xor(32|16|8) x y) -> (XORL x y)

(Neg(32|16|8)  x) -> (NEGL x)
(Neg32F x) && !config.use387 -> (PXOR x (MOVSSconst <typ.Float32> [f2i(math.Copysign(0, -1))]))
(Neg64F x) && !config.use387 -> (PXOR x (MOVSDconst <typ.Float64> [f2i(math.Copysign(0, -1))]))
(Neg32F x) && config.use387 -> (FCHS x)
(Neg64F x) && config.use387 -> (FCHS x)

(Com(32|16|8) x) -> (NOTL x)

// Lowering boolean ops
(AndB x y) -> (ANDL x y)
(OrB x y) -> (ORL x y)
(Not x) -> (XORLconst [1] x)

// Lowering pointer arithmetic
(OffPtr [off] ptr) -> (ADDLconst [off] ptr)

(Bswap32 x) -> (BSWAPL x)

(Sqrt x) -> (SQRTSD x)

// Lowering extension
(SignExt8to16  x) -> (MOVBLSX x)
(SignExt8to32  x) -> (MOVBLSX x)
(SignExt16to32 x) -> (MOVWLSX x)

(ZeroExt8to16  x) -> (MOVBLZX x)
(ZeroExt8to32  x) -> (MOVBLZX x)
(ZeroExt16to32 x) -> (MOVWLZX x)

(Signmask x) -> (SARLconst x [31])
(Zeromask <t> x) -> (XORLconst [-1] (SBBLcarrymask <t> (CMPLconst x [1])))
(Slicemask <t> x) -> (SARLconst (NEGL <t> x) [31])

// Lowering truncation
// Because we ignore high parts of registers, truncates are just copies.
(Trunc16to8  x) -> x
(Trunc32to8  x) -> x
(Trunc32to16 x) -> x

// Lowering float <-> int
(Cvt32to32F x) -> (CVTSL2SS x)
(Cvt32to64F x) -> (CVTSL2SD x)

(Cvt32Fto32 x) -> (CVTTSS2SL x)
(Cvt64Fto32 x) -> (CVTTSD2SL x)

(Cvt32Fto64F x) -> (CVTSS2SD x)
(Cvt64Fto32F x) -> (CVTSD2SS x)

(Round32F x) -> x
(Round64F x) -> x

// Lowering shifts
// Unsigned shifts need to return 0 if shift amount is >= width of shifted value.
//   result = (arg << shift) & (shift >= argbits ? 0 : 0xffffffffffffffff)
(Lsh32x32 <t> x y) -> (ANDL (SHLL <t> x y) (SBBLcarrymask <t> (CMPLconst y [32])))
(Lsh32x16 <t> x y) -> (ANDL (SHLL <t> x y) (SBBLcarrymask <t> (CMPWconst y [32])))
(Lsh32x8  <t> x y) -> (ANDL (SHLL <t> x y) (SBBLcarrymask <t> (CMPBconst y [32])))

(Lsh16x32 <t> x y) -> (ANDL (SHLL <t> x y) (SBBLcarrymask <t> (CMPLconst y [32])))
(Lsh16x16 <t> x y) -> (ANDL (SHLL <t> x y) (SBBLcarrymask <t> (CMPWconst y [32])))
(Lsh16x8  <t> x y) -> (ANDL (SHLL <t> x y) (SBBLcarrymask <t> (CMPBconst y [32])))

(Lsh8x32 <t> x y)  -> (ANDL (SHLL <t> x y) (SBBLcarrymask <t> (CMPLconst y [32])))
(Lsh8x16 <t> x y)  -> (ANDL (SHLL <t> x y) (SBBLcarrymask <t> (CMPWconst y [32])))
(Lsh8x8  <t> x y)  -> (ANDL (SHLL <t> x y) (SBBLcarrymask <t> (CMPBconst y [32])))

(Rsh32Ux32 <t> x y) -> (ANDL (SHRL <t> x y) (SBBLcarrymask <t> (CMPLconst y [32])))
(Rsh32Ux16 <t> x y) -> (ANDL (SHRL <t> x y) (SBBLcarrymask <t> (CMPWconst y [32])))
(Rsh32Ux8  <t> x y) -> (ANDL (SHRL <t> x y) (SBBLcarrymask <t> (CMPBconst y [32])))

(Rsh16Ux32 <t> x y) -> (ANDL (SHRW <t> x y) (SBBLcarrymask <t> (CMPLconst y [16])))
(Rsh16Ux16 <t> x y) -> (ANDL (SHRW <t> x y) (SBBLcarrymask <t> (CMPWconst y [16])))
(Rsh16Ux8  <t> x y) -> (ANDL (SHRW <t> x y) (SBBLcarrymask <t> (CMPBconst y [16])))

(Rsh8Ux32 <t> x y)  -> (ANDL (SHRB <t> x y) (SBBLcarrymask <t> (CMPLconst y [8])))
(Rsh8Ux16 <t> x y)  -> (ANDL (SHRB <t> x y) (SBBLcarrymask <t> (CMPWconst y [8])))
(Rsh8Ux8  <t> x y)  -> (ANDL (SHRB <t> x y) (SBBLcarrymask <t> (CMPBconst y [8])))

// Signed right shift needs to return 0/-1 if shift amount is >= width of shifted value.
// We implement this by setting the shift value to -1 (all ones) if the shift value is >= width.

(Rsh32x32 <t> x y) -> (SARL <t> x (ORL <y.Type> y (NOTL <y.Type> (SBBLcarrymask <y.Type> (CMPLconst y [32])))))
(Rsh32x16 <t> x y) -> (SARL <t> x (ORL <y.Type> y (NOTL <y.Type> (SBBLcarrymask <y.Type> (CMPWconst y [32])))))
(Rsh32x8  <t> x y) -> (SARL <t> x (ORL <y.Type> y (NOTL <y.Type> (SBBLcarrymask <y.Type> (CMPBconst y [32])))))

(Rsh16x32 <t> x y) -> (SARW <t> x (ORL <y.Type> y (NOTL <y.Type> (SBBLcarrymask <y.Type> (CMPLconst y [16])))))
(Rsh16x16 <t> x y) -> (SARW <t> x (ORL <y.Type> y (NOTL <y.Type> (SBBLcarrymask <y.Type> (CMPWconst y [16])))))
(Rsh16x8  <t> x y) -> (SARW <t> x (ORL <y.Type> y (NOTL <y.Type> (SBBLcarrymask <y.Type> (CMPBconst y [16])))))

(Rsh8x32 <t> x y)  -> (SARB <t> x (ORL <y.Type> y (NOTL <y.Type> (SBBLcarrymask <y.Type> (CMPLconst y [8])))))
(Rsh8x16 <t> x y)  -> (SARB <t> x (ORL <y.Type> y (NOTL <y.Type> (SBBLcarrymask <y.Type> (CMPWconst y [8])))))
(Rsh8x8  <t> x y)  -> (SARB <t> x (ORL <y.Type> y (NOTL <y.Type> (SBBLcarrymask <y.Type> (CMPBconst y [8])))))

// constant shifts
// generic opt rewrites all constant shifts to shift by Const64
(Lsh32x64 x (Const64 [c])) && uint64(c) < 32 -> (SHLLconst x [c])
(Rsh32x64 x (Const64 [c])) && uint64(c) < 32 -> (SARLconst x [c])
(Rsh32Ux64 x (Const64 [c])) && uint64(c) < 32 -> (SHRLconst x [c])
(Lsh16x64 x (Const64 [c])) && uint64(c) < 16 -> (SHLLconst x [c])
(Rsh16x64 x (Const64 [c])) && uint64(c) < 16 -> (SARWconst x [c])
(Rsh16Ux64 x (Const64 [c])) && uint64(c) < 16 -> (SHRWconst x [c])
(Lsh8x64 x (Const64 [c])) && uint64(c) < 8 -> (SHLLconst x [c])
(Rsh8x64 x (Const64 [c])) && uint64(c) < 8 -> (SARBconst x [c])
(Rsh8Ux64 x (Const64 [c])) && uint64(c) < 8 -> (SHRBconst x [c])

// large constant shifts
(Lsh32x64 _ (Const64 [c])) && uint64(c) >= 32 -> (Const32 [0])
(Rsh32Ux64 _ (Const64 [c])) && uint64(c) >= 32 -> (Const32 [0])
(Lsh16x64 _ (Const64 [c])) && uint64(c) >= 16 -> (Const16 [0])
(Rsh16Ux64 _ (Const64 [c])) && uint64(c) >= 16 -> (Const16 [0])
(Lsh8x64 _ (Const64 [c])) && uint64(c) >= 8 -> (Const8 [0])
(Rsh8Ux64 _ (Const64 [c])) && uint64(c) >= 8 -> (Const8 [0])

// large constant signed right shift, we leave the sign bit
(Rsh32x64 x (Const64 [c])) && uint64(c) >= 32 -> (SARLconst x [31])
(Rsh16x64 x (Const64 [c])) && uint64(c) >= 16 -> (SARWconst x [15])
(Rsh8x64 x (Const64 [c])) && uint64(c) >= 8 -> (SARBconst x [7])

// Lowering comparisons
(Less32  x y) -> (SETL (CMPL x y))
(Less16  x y) -> (SETL (CMPW x y))
(Less8   x y) -> (SETL (CMPB x y))
(Less32U x y) -> (SETB (CMPL x y))
(Less16U x y) -> (SETB (CMPW x y))
(Less8U  x y) -> (SETB (CMPB x y))
// Use SETGF with reversed operands to dodge NaN case
(Less64F x y) -> (SETGF (UCOMISD y x))
(Less32F x y) -> (SETGF (UCOMISS y x))

(Leq32  x y) -> (SETLE (CMPL x y))
(Leq16  x y) -> (SETLE (CMPW x y))
(Leq8   x y) -> (SETLE (CMPB x y))
(Leq32U x y) -> (SETBE (CMPL x y))
(Leq16U x y) -> (SETBE (CMPW x y))
(Leq8U  x y) -> (SETBE (CMPB x y))
// Use SETGEF with reversed operands to dodge NaN case
(Leq64F x y) -> (SETGEF (UCOMISD y x))
(Leq32F x y) -> (SETGEF (UCOMISS y x))

(Greater32  x y) -> (SETG (CMPL x y))
(Greater16  x y) -> (SETG (CMPW x y))
(Greater8   x y) -> (SETG (CMPB x y))
(Greater32U x y) -> (SETA (CMPL x y))
(Greater16U x y) -> (SETA (CMPW x y))
(Greater8U  x y) -> (SETA (CMPB x y))
// Note Go assembler gets UCOMISx operand order wrong, but it is right here
// Bug is accommodated at generation of assembly language.
(Greater64F x y) -> (SETGF (UCOMISD x y))
(Greater32F x y) -> (SETGF (UCOMISS x y))

(Geq32  x y) -> (SETGE (CMPL x y))
(Geq16  x y) -> (SETGE (CMPW x y))
(Geq8   x y) -> (SETGE (CMPB x y))
(Geq32U x y) -> (SETAE (CMPL x y))
(Geq16U x y) -> (SETAE (CMPW x y))
(Geq8U  x y) -> (SETAE (CMPB x y))
// Note Go assembler gets UCOMISx operand order wrong, but it is right here
// Bug is accommodated at generation of assembly language.
(Geq64F x y) -> (SETGEF (UCOMISD x y))
(Geq32F x y) -> (SETGEF (UCOMISS x y))

(Eq32  x y) -> (SETEQ (CMPL x y))
(Eq16  x y) -> (SETEQ (CMPW x y))
(Eq8   x y) -> (SETEQ (CMPB x y))
(EqB   x y) -> (SETEQ (CMPB x y))
(EqPtr x y) -> (SETEQ (CMPL x y))
(Eq64F x y) -> (SETEQF (UCOMISD x y))
(Eq32F x y) -> (SETEQF (UCOMISS x y))

(Neq32  x y) -> (SETNE (CMPL x y))
(Neq16  x y) -> (SETNE (CMPW x y))
(Neq8   x y) -> (SETNE (CMPB x y))
(NeqB   x y) -> (SETNE (CMPB x y))
(NeqPtr x y) -> (SETNE (CMPL x y))
(Neq64F x y) -> (SETNEF (UCOMISD x y))
(Neq32F x y) -> (SETNEF (UCOMISS x y))

// Lowering loads
(Load <t> ptr mem) && (is32BitInt(t) || isPtr(t)) -> (MOVLload ptr mem)
(Load <t> ptr mem) && is16BitInt(t) -> (MOVWload ptr mem)
(Load <t> ptr mem) && (t.IsBoolean() || is8BitInt(t)) -> (MOVBload ptr mem)
(Load <t> ptr mem) && is32BitFloat(t) -> (MOVSSload ptr mem)
(Load <t> ptr mem) && is64BitFloat(t) -> (MOVSDload ptr mem)

// Lowering stores
// These more-specific FP versions of Store pattern should come first.
(Store {t} ptr val mem) && t.(*types.Type).Size() == 8 && is64BitFloat(val.Type) -> (MOVSDstore ptr val mem)
(Store {t} ptr val mem) && t.(*types.Type).Size() == 4 && is32BitFloat(val.Type) -> (MOVSSstore ptr val mem)

(Store {t} ptr val mem) && t.(*types.Type).Size() == 4 -> (MOVLstore ptr val mem)
(Store {t} ptr val mem) && t.(*types.Type).Size() == 2 -> (MOVWstore ptr val mem)
(Store {t} ptr val mem) && t.(*types.Type).Size() == 1 -> (MOVBstore ptr val mem)

// Lowering moves
(Move [0] _ _ mem) -> mem
(Move [1] dst src mem) -> (MOVBstore dst (MOVBload src mem) mem)
(Move [2] dst src mem) -> (MOVWstore dst (MOVWload src mem) mem)
(Move [4] dst src mem) -> (MOVLstore dst (MOVLload src mem) mem)
(Move [3] dst src mem) ->
	(MOVBstore [2] dst (MOVBload [2] src mem)
		(MOVWstore dst (MOVWload src mem) mem))
(Move [5] dst src mem) ->
	(MOVBstore [4] dst (MOVBload [4] src mem)
		(MOVLstore dst (MOVLload src mem) mem))
(Move [6] dst src mem) ->
	(MOVWstore [4] dst (MOVWload [4] src mem)
		(MOVLstore dst (MOVLload src mem) mem))
(Move [7] dst src mem) ->
	(MOVLstore [3] dst (MOVLload [3] src mem)
		(MOVLstore dst (MOVLload src mem) mem))
(Move [8] dst src mem) ->
	(MOVLstore [4] dst (MOVLload [4] src mem)
		(MOVLstore dst (MOVLload src mem) mem))

// Adjust moves to be a multiple of 4 bytes.
(Move [s] dst src mem)
	&& s > 8 && s%4 != 0 ->
	(Move [s-s%4]
		(ADDLconst <dst.Type> dst [s%4])
		(ADDLconst <src.Type> src [s%4])
		(MOVLstore dst (MOVLload src mem) mem))

// Medium copying uses a duff device.
(Move [s] dst src mem)
	&& s > 8 && s <= 4*128 && s%4 == 0
	&& !config.noDuffDevice ->
	(DUFFCOPY [10*(128-s/4)] dst src mem)
// 10 and 128 are magic constants.  10 is the number of bytes to encode:
//	MOVL	(SI), CX
//	ADDL	$4, SI
//	MOVL	CX, (DI)
//	ADDL	$4, DI
// and 128 is the number of such blocks. See src/runtime/duff_386.s:duffcopy.

// Large copying uses REP MOVSL.
(Move [s] dst src mem) && (s > 4*128 || config.noDuffDevice) && s%4 == 0 ->
	(REPMOVSL dst src (MOVLconst [s/4]) mem)

// Lowering Zero instructions
(Zero [0] _ mem) -> mem
(Zero [1] destptr mem) -> (MOVBstoreconst [0] destptr mem)
(Zero [2] destptr mem) -> (MOVWstoreconst [0] destptr mem)
(Zero [4] destptr mem) -> (MOVLstoreconst [0] destptr mem)

(Zero [3] destptr mem) ->
	(MOVBstoreconst [makeValAndOff(0,2)] destptr
		(MOVWstoreconst [0] destptr mem))
(Zero [5] destptr mem) ->
	(MOVBstoreconst [makeValAndOff(0,4)] destptr
		(MOVLstoreconst [0] destptr mem))
(Zero [6] destptr mem) ->
	(MOVWstoreconst [makeValAndOff(0,4)] destptr
		(MOVLstoreconst [0] destptr mem))
(Zero [7] destptr mem) ->
	(MOVLstoreconst [makeValAndOff(0,3)] destptr
		(MOVLstoreconst [0] destptr mem))

// Strip off any fractional word zeroing.
(Zero [s] destptr mem) && s%4 != 0 && s > 4 ->
	(Zero [s-s%4] (ADDLconst destptr [s%4])
		(MOVLstoreconst [0] destptr mem))

// Zero small numbers of words directly.
(Zero [8] destptr mem) ->
	(MOVLstoreconst [makeValAndOff(0,4)] destptr
		(MOVLstoreconst [0] destptr mem))
(Zero [12] destptr mem) ->
	(MOVLstoreconst [makeValAndOff(0,8)] destptr
		(MOVLstoreconst [makeValAndOff(0,4)] destptr
			(MOVLstoreconst [0] destptr mem)))
(Zero [16] destptr mem) ->
	(MOVLstoreconst [makeValAndOff(0,12)] destptr
		(MOVLstoreconst [makeValAndOff(0,8)] destptr
			(MOVLstoreconst [makeValAndOff(0,4)] destptr
				(MOVLstoreconst [0] destptr mem))))

// Medium zeroing uses a duff device.
(Zero [s] destptr mem)
  && s > 16 && s <= 4*128 && s%4 == 0
  && !config.noDuffDevice ->
	(DUFFZERO [1*(128-s/4)] destptr (MOVLconst [0]) mem)
// 1 and 128 are magic constants.  1 is the number of bytes to encode STOSL.
// 128 is the number of STOSL instructions in duffzero.
// See src/runtime/duff_386.s:duffzero.

// Large zeroing uses REP STOSQ.
(Zero [s] destptr mem)
  && (s > 4*128 || (config.noDuffDevice && s > 16))
  && s%4 == 0 ->
	(REPSTOSL destptr (MOVLconst [s/4]) (MOVLconst [0]) mem)

// Lowering constants
(Const(8|16|32)   [val]) -> (MOVLconst [val])
(Const(32|64)F [val]) -> (MOVS(S|D)const [val])
(ConstNil) -> (MOVLconst [0])
(ConstBool [b]) -> (MOVLconst [b])

// Lowering calls
(StaticCall [argwid] {target} mem) -> (CALLstatic [argwid] {target} mem)
(ClosureCall [argwid] entry closure mem) -> (CALLclosure [argwid] entry closure mem)
(InterCall [argwid] entry mem) -> (CALLinter [argwid] entry mem)

// Miscellaneous
(Convert <t> x mem) -> (MOVLconvert <t> x mem)
(IsNonNil p) -> (SETNE (TESTL p p))
(IsInBounds idx len) -> (SETB (CMPL idx len))
(IsSliceInBounds idx len) -> (SETBE (CMPL idx len))
(NilCheck ptr mem) -> (LoweredNilCheck ptr mem)
(GetG mem) -> (LoweredGetG mem)
(GetClosurePtr) -> (LoweredGetClosurePtr)
(GetCallerPC) -> (LoweredGetCallerPC)
(GetCallerSP) -> (LoweredGetCallerSP)
(Addr {sym} base) -> (LEAL {sym} base)

// block rewrites
(If (SETL  cmp) yes no) -> (LT  cmp yes no)
(If (SETLE cmp) yes no) -> (LE  cmp yes no)
(If (SETG  cmp) yes no) -> (GT  cmp yes no)
(If (SETGE cmp) yes no) -> (GE  cmp yes no)
(If (SETEQ cmp) yes no) -> (EQ  cmp yes no)
(If (SETNE cmp) yes no) -> (NE  cmp yes no)
(If (SETB  cmp) yes no) -> (ULT cmp yes no)
(If (SETBE cmp) yes no) -> (ULE cmp yes no)
(If (SETA  cmp) yes no) -> (UGT cmp yes no)
(If (SETAE cmp) yes no) -> (UGE cmp yes no)

// Special case for floating point - LF/LEF not generated
(If (SETGF  cmp) yes no) -> (UGT  cmp yes no)
(If (SETGEF cmp) yes no) -> (UGE  cmp yes no)
(If (SETEQF cmp) yes no) -> (EQF  cmp yes no)
(If (SETNEF cmp) yes no) -> (NEF  cmp yes no)

(If cond yes no) -> (NE (TESTB cond cond) yes no)

// Write barrier.
(WB {fn} destptr srcptr mem) -> (LoweredWB {fn} destptr srcptr mem)

// ***************************
// Above: lowering rules
// Below: optimizations
// ***************************
// TODO: Should the optimizations be a separate pass?

// Fold boolean tests into blocks
(NE (TESTB (SETL  cmp) (SETL  cmp)) yes no) -> (LT  cmp yes no)
(NE (TESTB (SETLE cmp) (SETLE cmp)) yes no) -> (LE  cmp yes no)
(NE (TESTB (SETG  cmp) (SETG  cmp)) yes no) -> (GT  cmp yes no)
(NE (TESTB (SETGE cmp) (SETGE cmp)) yes no) -> (GE  cmp yes no)
(NE (TESTB (SETEQ cmp) (SETEQ cmp)) yes no) -> (EQ  cmp yes no)
(NE (TESTB (SETNE cmp) (SETNE cmp)) yes no) -> (NE  cmp yes no)
(NE (TESTB (SETB  cmp) (SETB  cmp)) yes no) -> (ULT cmp yes no)
(NE (TESTB (SETBE cmp) (SETBE cmp)) yes no) -> (ULE cmp yes no)
(NE (TESTB (SETA  cmp) (SETA  cmp)) yes no) -> (UGT cmp yes no)
(NE (TESTB (SETAE cmp) (SETAE cmp)) yes no) -> (UGE cmp yes no)

// Special case for floating point - LF/LEF not generated
(NE (TESTB (SETGF  cmp) (SETGF  cmp)) yes no) -> (UGT  cmp yes no)
(NE (TESTB (SETGEF cmp) (SETGEF cmp)) yes no) -> (UGE  cmp yes no)
(NE (TESTB (SETEQF cmp) (SETEQF cmp)) yes no) -> (EQF  cmp yes no)
(NE (TESTB (SETNEF cmp) (SETNEF cmp)) yes no) -> (NEF  cmp yes no)

// fold constants into instructions
(ADDL x (MOVLconst [c])) -> (ADDLconst [c] x)
(ADDLcarry x (MOVLconst [c])) -> (ADDLconstcarry [c] x)
(ADCL x (MOVLconst [c]) f) -> (ADCLconst [c] x f)
(ADCL (MOVLconst [c]) x f) -> (ADCLconst [c] x f)

(SUBL x (MOVLconst [c])) -> (SUBLconst x [c])
(SUBL (MOVLconst [c]) x) -> (NEGL (SUBLconst <v.Type> x [c]))
(SUBLcarry x (MOVLconst [c])) -> (SUBLconstcarry [c] x)
(SBBL x (MOVLconst [c]) f) -> (SBBLconst [c] x f)

(MULL x (MOVLconst [c])) -> (MULLconst [c] x)

(ANDL x (MOVLconst [c])) -> (ANDLconst [c] x)

(ANDLconst [c] (ANDLconst [d] x)) -> (ANDLconst [c & d] x)

(XORLconst [c] (XORLconst [d] x)) -> (XORLconst [c ^ d] x)

(MULLconst [c] (MULLconst [d] x)) -> (MULLconst [int64(int32(c * d))] x)

(ORL x (MOVLconst [c])) -> (ORLconst [c] x)

(XORL x (MOVLconst [c])) -> (XORLconst [c] x)

(SHLL x (MOVLconst [c])) -> (SHLLconst [c&31] x)
(SHRL x (MOVLconst [c])) -> (SHRLconst [c&31] x)
(SHRW x (MOVLconst [c])) && c&31 < 16 -> (SHRWconst [c&31] x)
(SHRW _ (MOVLconst [c])) && c&31 >= 16 -> (MOVLconst [0])
(SHRB x (MOVLconst [c])) && c&31 < 8 -> (SHRBconst [c&31] x)
(SHRB _ (MOVLconst [c])) && c&31 >= 8 -> (MOVLconst [0])

(SARL x (MOVLconst [c])) -> (SARLconst [c&31] x)
(SARW x (MOVLconst [c])) -> (SARWconst [min(c&31,15)] x)
(SARB x (MOVLconst [c])) -> (SARBconst [min(c&31,7)] x)

(SARL x (ANDLconst [31] y)) -> (SARL x y)

(SHLL x (ANDLconst [31] y)) -> (SHLL x y)

(SHRL x (ANDLconst [31] y)) -> (SHRL x y)

// Rotate instructions

(ADDL (SHLLconst [c] x) (SHRLconst [d] x)) && d == 32-c -> (ROLLconst [c] x)
( ORL (SHLLconst [c] x) (SHRLconst [d] x)) && d == 32-c -> (ROLLconst [c] x)
(XORL (SHLLconst [c] x) (SHRLconst [d] x)) && d == 32-c -> (ROLLconst [c] x)

(ADDL <t> (SHLLconst x [c]) (SHRWconst x [d])) && c < 16 && d == 16-c && t.Size() == 2 -> (ROLWconst x [c])
( ORL <t> (SHLLconst x [c]) (SHRWconst x [d])) && c < 16 && d == 16-c && t.Size() == 2 -> (ROLWconst x [c])
(XORL <t> (SHLLconst x [c]) (SHRWconst x [d])) && c < 16 && d == 16-c && t.Size() == 2 -> (ROLWconst x [c])

(ADDL <t> (SHLLconst x [c]) (SHRBconst x [d])) && c < 8 && d == 8-c && t.Size() == 1 -> (ROLBconst x [c])
( ORL <t> (SHLLconst x [c]) (SHRBconst x [d])) && c < 8 && d == 8-c && t.Size() == 1 -> (ROLBconst x [c])
(XORL <t> (SHLLconst x [c]) (SHRBconst x [d])) && c < 8 && d == 8-c && t.Size() == 1 -> (ROLBconst x [c])

(ROLLconst [c] (ROLLconst [d] x)) -> (ROLLconst [(c+d)&31] x)
(ROLWconst [c] (ROLWconst [d] x)) -> (ROLWconst [(c+d)&15] x)
(ROLBconst [c] (ROLBconst [d] x)) -> (ROLBconst [(c+d)& 7] x)

// Constant shift simplifications

(SHLLconst x [0]) -> x
(SHRLconst x [0]) -> x
(SARLconst x [0]) -> x

(SHRWconst x [0]) -> x
(SARWconst x [0]) -> x

(SHRBconst x [0]) -> x
(SARBconst x [0]) -> x

(ROLLconst [0] x) -> x
(ROLWconst [0] x) -> x
(ROLBconst [0] x) -> x

// Note: the word and byte shifts keep the low 5 bits (not the low 4 or 3 bits)
// because the x86 instructions are defined to use all 5 bits of the shift even
// for the small shifts. I don't think we'll ever generate a weird shift (e.g.
// (SHRW x (MOVLconst [24])), but just in case.

(CMPL x (MOVLconst [c])) -> (CMPLconst x [c])
(CMPL (MOVLconst [c]) x) -> (InvertFlags (CMPLconst x [c]))
(CMPW x (MOVLconst [c])) -> (CMPWconst x [int64(int16(c))])
(CMPW (MOVLconst [c]) x) -> (InvertFlags (CMPWconst x [int64(int16(c))]))
(CMPB x (MOVLconst [c])) -> (CMPBconst x [int64(int8(c))])
(CMPB (MOVLconst [c]) x) -> (InvertFlags (CMPBconst x [int64(int8(c))]))

// strength reduction
// Assumes that the following costs from https://gmplib.org/~tege/x86-timing.pdf:
//    1 - addq, shlq, leaq, negq
//    3 - imulq
// This limits the rewrites to two instructions.
// TODO: 27, 81
(MULLconst [-1] x) -> (NEGL x)
(MULLconst [0] _) -> (MOVLconst [0])
(MULLconst [1] x) -> x
(MULLconst [3] x) -> (LEAL2 x x)
(MULLconst [5] x) -> (LEAL4 x x)
(MULLconst [7] x) -> (LEAL8 (NEGL <v.Type> x) x)
(MULLconst [9] x) -> (LEAL8 x x)
(MULLconst [11] x) -> (LEAL2 x (LEAL4 <v.Type> x x))
(MULLconst [13] x) -> (LEAL4 x (LEAL2 <v.Type> x x))
(MULLconst [21] x) -> (LEAL4 x (LEAL4 <v.Type> x x))
(MULLconst [25] x) -> (LEAL8 x (LEAL2 <v.Type> x x))
(MULLconst [37] x) -> (LEAL4 x (LEAL8 <v.Type> x x))
(MULLconst [41] x) -> (LEAL8 x (LEAL4 <v.Type> x x))
(MULLconst [73] x) -> (LEAL8 x (LEAL8 <v.Type> x x))

(MULLconst [c] x) && isPowerOfTwo(c+1) && c >= 15 -> (SUBL (SHLLconst <v.Type> [log2(c+1)] x) x)
(MULLconst [c] x) && isPowerOfTwo(c-1) && c >= 17 -> (LEAL1 (SHLLconst <v.Type> [log2(c-1)] x) x)
(MULLconst [c] x) && isPowerOfTwo(c-2) && c >= 34 -> (LEAL2 (SHLLconst <v.Type> [log2(c-2)] x) x)
(MULLconst [c] x) && isPowerOfTwo(c-4) && c >= 68 -> (LEAL4 (SHLLconst <v.Type> [log2(c-4)] x) x)
(MULLconst [c] x) && isPowerOfTwo(c-8) && c >= 136 -> (LEAL8 (SHLLconst <v.Type> [log2(c-8)] x) x)
(MULLconst [c] x) && c%3 == 0 && isPowerOfTwo(c/3) -> (SHLLconst [log2(c/3)] (LEAL2 <v.Type> x x))
(MULLconst [c] x) && c%5 == 0 && isPowerOfTwo(c/5) -> (SHLLconst [log2(c/5)] (LEAL4 <v.Type> x x))
(MULLconst [c] x) && c%9 == 0 && isPowerOfTwo(c/9) -> (SHLLconst [log2(c/9)] (LEAL8 <v.Type> x x))

// combine add/shift into LEAL
(ADDL x (SHLLconst [3] y)) -> (LEAL8 x y)
(ADDL x (SHLLconst [2] y)) -> (LEAL4 x y)
(ADDL x (SHLLconst [1] y)) -> (LEAL2 x y)
(ADDL x (ADDL y y)) -> (LEAL2 x y)
(ADDL x (ADDL x y)) -> (LEAL2 y x)

// combine ADDL/ADDLconst into LEAL1
(ADDLconst [c] (ADDL x y)) -> (LEAL1 [c] x y)
(ADDL (ADDLconst [c] x) y) -> (LEAL1 [c] x y)

// fold ADDL into LEAL
(ADDLconst [c] (LEAL [d] {s} x)) && is32Bit(c+d) -> (LEAL [c+d] {s} x)
(LEAL [c] {s} (ADDLconst [d] x)) && is32Bit(c+d) -> (LEAL [c+d] {s} x)
(LEAL [c] {s} (ADDL x y)) && x.Op != OpSB && y.Op != OpSB -> (LEAL1 [c] {s} x y)
(ADDL x (LEAL [c] {s} y)) && x.Op != OpSB && y.Op != OpSB -> (LEAL1 [c] {s} x y)

// fold ADDLconst into LEALx
(ADDLconst [c] (LEAL1 [d] {s} x y)) && is32Bit(c+d) -> (LEAL1 [c+d] {s} x y)
(ADDLconst [c] (LEAL2 [d] {s} x y)) && is32Bit(c+d) -> (LEAL2 [c+d] {s} x y)
(ADDLconst [c] (LEAL4 [d] {s} x y)) && is32Bit(c+d) -> (LEAL4 [c+d] {s} x y)
(ADDLconst [c] (LEAL8 [d] {s} x y)) && is32Bit(c+d) -> (LEAL8 [c+d] {s} x y)
(LEAL1 [c] {s} (ADDLconst [d] x) y) && is32Bit(c+d)   && x.Op != OpSB -> (LEAL1 [c+d] {s} x y)
(LEAL2 [c] {s} (ADDLconst [d] x) y) && is32Bit(c+d)   && x.Op != OpSB -> (LEAL2 [c+d] {s} x y)
(LEAL2 [c] {s} x (ADDLconst [d] y)) && is32Bit(c+2*d) && y.Op != OpSB -> (LEAL2 [c+2*d] {s} x y)
(LEAL4 [c] {s} (ADDLconst [d] x) y) && is32Bit(c+d)   && x.Op != OpSB -> (LEAL4 [c+d] {s} x y)
(LEAL4 [c] {s} x (ADDLconst [d] y)) && is32Bit(c+4*d) && y.Op != OpSB -> (LEAL4 [c+4*d] {s} x y)
(LEAL8 [c] {s} (ADDLconst [d] x) y) && is32Bit(c+d)   && x.Op != OpSB -> (LEAL8 [c+d] {s} x y)
(LEAL8 [c] {s} x (ADDLconst [d] y)) && is32Bit(c+8*d) && y.Op != OpSB -> (LEAL8 [c+8*d] {s} x y)

// fold shifts into LEALx
(LEAL1 [c] {s} x (SHLLconst [1] y)) -> (LEAL2 [c] {s} x y)
(LEAL1 [c] {s} x (SHLLconst [2] y)) -> (LEAL4 [c] {s} x y)
(LEAL1 [c] {s} x (SHLLconst [3] y)) -> (LEAL8 [c] {s} x y)
(LEAL2 [c] {s} x (SHLLconst [1] y)) -> (LEAL4 [c] {s} x y)
(LEAL2 [c] {s} x (SHLLconst [2] y)) -> (LEAL8 [c] {s} x y)
(LEAL4 [c] {s} x (SHLLconst [1] y)) -> (LEAL8 [c] {s} x y)

// reverse ordering of compare instruction
(SETL (InvertFlags x)) -> (SETG x)
(SETG (InvertFlags x)) -> (SETL x)
(SETB (InvertFlags x)) -> (SETA x)
(SETA (InvertFlags x)) -> (SETB x)
(SETLE (InvertFlags x)) -> (SETGE x)
(SETGE (InvertFlags x)) -> (SETLE x)
(SETBE (InvertFlags x)) -> (SETAE x)
(SETAE (InvertFlags x)) -> (SETBE x)
(SETEQ (InvertFlags x)) -> (SETEQ x)
(SETNE (InvertFlags x)) -> (SETNE x)

// sign extended loads
// Note: The combined instruction must end up in the same block
// as the original load. If not, we end up making a value with
// memory type live in two different blocks, which can lead to
// multiple memory values alive simultaneously.
// Make sure we don't combine these ops if the load has another use.
// This prevents a single load from being split into multiple loads
// which then might return different values.  See test/atomicload.go.
(MOVBLSX x:(MOVBload [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) -> @x.Block (MOVBLSXload <v.Type> [off] {sym} ptr mem)
(MOVBLZX x:(MOVBload [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) -> @x.Block (MOVBload <v.Type> [off] {sym} ptr mem)
(MOVWLSX x:(MOVWload [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) -> @x.Block (MOVWLSXload <v.Type> [off] {sym} ptr mem)
(MOVWLZX x:(MOVWload [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) -> @x.Block (MOVWload <v.Type> [off] {sym} ptr mem)

(MOVBLZX x:(MOVBloadidx1 [off] {sym} ptr idx mem)) && x.Uses == 1 && clobber(x) -> @x.Block (MOVBloadidx1 <v.Type> [off] {sym} ptr idx mem)
(MOVWLZX x:(MOVWloadidx1 [off] {sym} ptr idx mem)) && x.Uses == 1 && clobber(x) -> @x.Block (MOVWloadidx1 <v.Type> [off] {sym} ptr idx mem)
(MOVWLZX x:(MOVWloadidx2 [off] {sym} ptr idx mem)) && x.Uses == 1 && clobber(x) -> @x.Block (MOVWloadidx2 <v.Type> [off] {sym} ptr idx mem)

// replace load from same location as preceding store with zero/sign extension (or copy in case of full width)
(MOVBload [off] {sym} ptr (MOVBstore [off2] {sym2} ptr2 x _)) && sym == sym2 && off == off2 && isSamePtr(ptr, ptr2) -> (MOVBLZX x)
(MOVWload [off] {sym} ptr (MOVWstore [off2] {sym2} ptr2 x _)) && sym == sym2 && off == off2 && isSamePtr(ptr, ptr2) -> (MOVWLZX x)
(MOVLload [off] {sym} ptr (MOVLstore [off2] {sym2} ptr2 x _)) && sym == sym2 && off == off2 && isSamePtr(ptr, ptr2) -> x
(MOVBLSXload [off] {sym} ptr (MOVBstore [off2] {sym2} ptr2 x _)) && sym == sym2 && off == off2 && isSamePtr(ptr, ptr2) -> (MOVBLSX x)
(MOVWLSXload [off] {sym} ptr (MOVWstore [off2] {sym2} ptr2 x _)) && sym == sym2 && off == off2 && isSamePtr(ptr, ptr2) -> (MOVWLSX x)

// Fold extensions and ANDs together.
(MOVBLZX (ANDLconst [c] x)) -> (ANDLconst [c & 0xff] x)
(MOVWLZX (ANDLconst [c] x)) -> (ANDLconst [c & 0xffff] x)
(MOVBLSX (ANDLconst [c] x)) && c & 0x80 == 0 -> (ANDLconst [c & 0x7f] x)
(MOVWLSX (ANDLconst [c] x)) && c & 0x8000 == 0 -> (ANDLconst [c & 0x7fff] x)

// Don't extend before storing
(MOVWstore [off] {sym} ptr (MOVWLSX x) mem) -> (MOVWstore [off] {sym} ptr x mem)
(MOVBstore [off] {sym} ptr (MOVBLSX x) mem) -> (MOVBstore [off] {sym} ptr x mem)
(MOVWstore [off] {sym} ptr (MOVWLZX x) mem) -> (MOVWstore [off] {sym} ptr x mem)
(MOVBstore [off] {sym} ptr (MOVBLZX x) mem) -> (MOVBstore [off] {sym} ptr x mem)

// fold constants into memory operations
// Note that this is not always a good idea because if not all the uses of
// the ADDQconst get eliminated, we still have to compute the ADDQconst and we now
// have potentially two live values (ptr and (ADDQconst [off] ptr)) instead of one.
// Nevertheless, let's do it!
(MOVLload  [off1] {sym} (ADDLconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVLload  [off1+off2] {sym} ptr mem)
(MOVWload  [off1] {sym} (ADDLconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVWload  [off1+off2] {sym} ptr mem)
(MOVBload  [off1] {sym} (ADDLconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVBload  [off1+off2] {sym} ptr mem)
(MOVSSload [off1] {sym} (ADDLconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVSSload [off1+off2] {sym} ptr mem)
(MOVSDload [off1] {sym} (ADDLconst [off2] ptr) mem) && is32Bit(off1+off2) -> (MOVSDload [off1+off2] {sym} ptr mem)

(MOVLstore  [off1] {sym} (ADDLconst [off2] ptr) val mem) && is32Bit(off1+off2) -> (MOVLstore  [off1+off2] {sym} ptr val mem)
(MOVWstore  [off1] {sym} (ADDLconst [off2] ptr) val mem) && is32Bit(off1+off2) -> (MOVWstore  [off1+off2] {sym} ptr val mem)
(MOVBstore  [off1] {sym} (ADDLconst [off2] ptr) val mem) && is32Bit(off1+off2) -> (MOVBstore  [off1+off2] {sym} ptr val mem)
(MOVSSstore [off1] {sym} (ADDLconst [off2] ptr) val mem) && is32Bit(off1+off2) -> (MOVSSstore [off1+off2] {sym} ptr val mem)
(MOVSDstore [off1] {sym} (ADDLconst [off2] ptr) val mem) && is32Bit(off1+off2) -> (MOVSDstore [off1+off2] {sym} ptr val mem)

// Fold constants into stores.
(MOVLstore [off] {sym} ptr (MOVLconst [c]) mem) && validOff(off) ->
	(MOVLstoreconst [makeValAndOff(int64(int32(c)),off)] {sym} ptr mem)
(MOVWstore [off] {sym} ptr (MOVLconst [c]) mem) && validOff(off) ->
	(MOVWstoreconst [makeValAndOff(int64(int16(c)),off)] {sym} ptr mem)
(MOVBstore [off] {sym} ptr (MOVLconst [c]) mem) && validOff(off) ->
	(MOVBstoreconst [makeValAndOff(int64(int8(c)),off)] {sym} ptr mem)

// Fold address offsets into constant stores.
(MOVLstoreconst [sc] {s} (ADDLconst [off] ptr) mem) && ValAndOff(sc).canAdd(off) ->
	(MOVLstoreconst [ValAndOff(sc).add(off)] {s} ptr mem)
(MOVWstoreconst [sc] {s} (ADDLconst [off] ptr) mem) && ValAndOff(sc).canAdd(off) ->
	(MOVWstoreconst [ValAndOff(sc).add(off)] {s} ptr mem)
(MOVBstoreconst [sc] {s} (ADDLconst [off] ptr) mem) && ValAndOff(sc).canAdd(off) ->
	(MOVBstoreconst [ValAndOff(sc).add(off)] {s} ptr mem)

// We need to fold LEAQ into the MOVx ops so that the live variable analysis knows
// what variables are being read/written by the ops.
// Note: we turn off this merging for operations on globals when building
// position-independent code (when Flag_shared is set).
// PIC needs a spare register to load the PC into.  Having the LEAL be
// a separate instruction gives us that register.  Having the LEAL be
// a separate instruction also allows it to be CSEd (which is good because
// it compiles to a thunk call).
(MOVLload  [off1] {sym1} (LEAL [off2] {sym2} base) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVLload  [off1+off2] {mergeSym(sym1,sym2)} base mem)
(MOVWload  [off1] {sym1} (LEAL [off2] {sym2} base) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVWload  [off1+off2] {mergeSym(sym1,sym2)} base mem)
(MOVBload  [off1] {sym1} (LEAL [off2] {sym2} base) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVBload  [off1+off2] {mergeSym(sym1,sym2)} base mem)
(MOVSSload [off1] {sym1} (LEAL [off2] {sym2} base) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVSSload [off1+off2] {mergeSym(sym1,sym2)} base mem)
(MOVSDload [off1] {sym1} (LEAL [off2] {sym2} base) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVSDload [off1+off2] {mergeSym(sym1,sym2)} base mem)

(MOVBLSXload [off1] {sym1} (LEAL [off2] {sym2} base) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVBLSXload [off1+off2] {mergeSym(sym1,sym2)} base mem)
(MOVWLSXload [off1] {sym1} (LEAL [off2] {sym2} base) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVWLSXload [off1+off2] {mergeSym(sym1,sym2)} base mem)

(MOVLstore  [off1] {sym1} (LEAL [off2] {sym2} base) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVLstore  [off1+off2] {mergeSym(sym1,sym2)} base val mem)
(MOVWstore  [off1] {sym1} (LEAL [off2] {sym2} base) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVWstore  [off1+off2] {mergeSym(sym1,sym2)} base val mem)
(MOVBstore  [off1] {sym1} (LEAL [off2] {sym2} base) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVBstore  [off1+off2] {mergeSym(sym1,sym2)} base val mem)
(MOVSSstore [off1] {sym1} (LEAL [off2] {sym2} base) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVSSstore [off1+off2] {mergeSym(sym1,sym2)} base val mem)
(MOVSDstore [off1] {sym1} (LEAL [off2] {sym2} base) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2)
  && (base.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVSDstore [off1+off2] {mergeSym(sym1,sym2)} base val mem)

(MOVLstoreconst [sc] {sym1} (LEAL [off] {sym2} ptr) mem) && canMergeSym(sym1, sym2) && ValAndOff(sc).canAdd(off)
  && (ptr.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVLstoreconst [ValAndOff(sc).add(off)] {mergeSym(sym1, sym2)} ptr mem)
(MOVWstoreconst [sc] {sym1} (LEAL [off] {sym2} ptr) mem) && canMergeSym(sym1, sym2) && ValAndOff(sc).canAdd(off)
  && (ptr.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVWstoreconst [ValAndOff(sc).add(off)] {mergeSym(sym1, sym2)} ptr mem)
(MOVBstoreconst [sc] {sym1} (LEAL [off] {sym2} ptr) mem) && canMergeSym(sym1, sym2) && ValAndOff(sc).canAdd(off)
  && (ptr.Op != OpSB || !config.ctxt.Flag_shared) ->
	(MOVBstoreconst [ValAndOff(sc).add(off)] {mergeSym(sym1, sym2)} ptr mem)

// generating indexed loads and stores
(MOVBload [off1] {sym1} (LEAL1 [off2] {sym2} ptr idx) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVBloadidx1 [off1+off2] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVWload [off1] {sym1} (LEAL1 [off2] {sym2} ptr idx) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVWloadidx1 [off1+off2] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVWload [off1] {sym1} (LEAL2 [off2] {sym2} ptr idx) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVWloadidx2 [off1+off2] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVLload [off1] {sym1} (LEAL1 [off2] {sym2} ptr idx) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVLloadidx1 [off1+off2] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVLload [off1] {sym1} (LEAL4 [off2] {sym2} ptr idx) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVLloadidx4 [off1+off2] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVSSload [off1] {sym1} (LEAL1 [off2] {sym2} ptr idx) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVSSloadidx1 [off1+off2] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVSSload [off1] {sym1} (LEAL4 [off2] {sym2} ptr idx) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVSSloadidx4 [off1+off2] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVSDload [off1] {sym1} (LEAL1 [off2] {sym2} ptr idx) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVSDloadidx1 [off1+off2] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVSDload [off1] {sym1} (LEAL8 [off2] {sym2} ptr idx) mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVSDloadidx8 [off1+off2] {mergeSym(sym1,sym2)} ptr idx mem)

(MOVBstore [off1] {sym1} (LEAL1 [off2] {sym2} ptr idx) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVBstoreidx1 [off1+off2] {mergeSym(sym1,sym2)} ptr idx val mem)
(MOVWstore [off1] {sym1} (LEAL1 [off2] {sym2} ptr idx) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVWstoreidx1 [off1+off2] {mergeSym(sym1,sym2)} ptr idx val mem)
(MOVWstore [off1] {sym1} (LEAL2 [off2] {sym2} ptr idx) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVWstoreidx2 [off1+off2] {mergeSym(sym1,sym2)} ptr idx val mem)
(MOVLstore [off1] {sym1} (LEAL1 [off2] {sym2} ptr idx) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVLstoreidx1 [off1+off2] {mergeSym(sym1,sym2)} ptr idx val mem)
(MOVLstore [off1] {sym1} (LEAL4 [off2] {sym2} ptr idx) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVLstoreidx4 [off1+off2] {mergeSym(sym1,sym2)} ptr idx val mem)
(MOVSSstore [off1] {sym1} (LEAL1 [off2] {sym2} ptr idx) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVSSstoreidx1 [off1+off2] {mergeSym(sym1,sym2)} ptr idx val mem)
(MOVSSstore [off1] {sym1} (LEAL4 [off2] {sym2} ptr idx) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVSSstoreidx4 [off1+off2] {mergeSym(sym1,sym2)} ptr idx val mem)
(MOVSDstore [off1] {sym1} (LEAL1 [off2] {sym2} ptr idx) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVSDstoreidx1 [off1+off2] {mergeSym(sym1,sym2)} ptr idx val mem)
(MOVSDstore [off1] {sym1} (LEAL8 [off2] {sym2} ptr idx) val mem) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
	(MOVSDstoreidx8 [off1+off2] {mergeSym(sym1,sym2)} ptr idx val mem)

(MOVBload [off] {sym} (ADDL ptr idx) mem) && ptr.Op != OpSB -> (MOVBloadidx1 [off] {sym} ptr idx mem)
(MOVWload [off] {sym} (ADDL ptr idx) mem) && ptr.Op != OpSB -> (MOVWloadidx1 [off] {sym} ptr idx mem)
(MOVLload [off] {sym} (ADDL ptr idx) mem) && ptr.Op != OpSB -> (MOVLloadidx1 [off] {sym} ptr idx mem)
(MOVSSload [off] {sym} (ADDL ptr idx) mem) && ptr.Op != OpSB -> (MOVSSloadidx1 [off] {sym} ptr idx mem)
(MOVSDload [off] {sym} (ADDL ptr idx) mem) && ptr.Op != OpSB -> (MOVSDloadidx1 [off] {sym} ptr idx mem)
(MOVBstore [off] {sym} (ADDL ptr idx) val mem) && ptr.Op != OpSB -> (MOVBstoreidx1 [off] {sym} ptr idx val mem)
(MOVWstore [off] {sym} (ADDL ptr idx) val mem) && ptr.Op != OpSB -> (MOVWstoreidx1 [off] {sym} ptr idx val mem)
(MOVLstore [off] {sym} (ADDL ptr idx) val mem) && ptr.Op != OpSB -> (MOVLstoreidx1 [off] {sym} ptr idx val mem)
(MOVSSstore [off] {sym} (ADDL ptr idx) val mem) && ptr.Op != OpSB -> (MOVSSstoreidx1 [off] {sym} ptr idx val mem)
(MOVSDstore [off] {sym} (ADDL ptr idx) val mem) && ptr.Op != OpSB -> (MOVSDstoreidx1 [off] {sym} ptr idx val mem)

(MOVBstoreconst [x] {sym1} (LEAL1 [off] {sym2} ptr idx) mem) && canMergeSym(sym1, sym2) ->
	(MOVBstoreconstidx1 [ValAndOff(x).add(off)] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVWstoreconst [x] {sym1} (LEAL1 [off] {sym2} ptr idx) mem) && canMergeSym(sym1, sym2) ->
	(MOVWstoreconstidx1 [ValAndOff(x).add(off)] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVWstoreconst [x] {sym1} (LEAL2 [off] {sym2} ptr idx) mem) && canMergeSym(sym1, sym2) ->
	(MOVWstoreconstidx2 [ValAndOff(x).add(off)] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVLstoreconst [x] {sym1} (LEAL1 [off] {sym2} ptr idx) mem) && canMergeSym(sym1, sym2) ->
	(MOVLstoreconstidx1 [ValAndOff(x).add(off)] {mergeSym(sym1,sym2)} ptr idx mem)
(MOVLstoreconst [x] {sym1} (LEAL4 [off] {sym2} ptr idx) mem) && canMergeSym(sym1, sym2) ->
	(MOVLstoreconstidx4 [ValAndOff(x).add(off)] {mergeSym(sym1,sym2)} ptr idx mem)

(MOVBstoreconst [x] {sym} (ADDL ptr idx) mem) -> (MOVBstoreconstidx1 [x] {sym} ptr idx mem)
(MOVWstoreconst [x] {sym} (ADDL ptr idx) mem) -> (MOVWstoreconstidx1 [x] {sym} ptr idx mem)
(MOVLstoreconst [x] {sym} (ADDL ptr idx) mem) -> (MOVLstoreconstidx1 [x] {sym} ptr idx mem)

// combine SHLL into indexed loads and stores
(MOVWloadidx1 [c] {sym} ptr (SHLLconst [1] idx) mem) -> (MOVWloadidx2 [c] {sym} ptr idx mem)
(MOVLloadidx1 [c] {sym} ptr (SHLLconst [2] idx) mem) -> (MOVLloadidx4 [c] {sym} ptr idx mem)
(MOVWstoreidx1 [c] {sym} ptr (SHLLconst [1] idx) val mem) -> (MOVWstoreidx2 [c] {sym} ptr idx val mem)
(MOVLstoreidx1 [c] {sym} ptr (SHLLconst [2] idx) val mem) -> (MOVLstoreidx4 [c] {sym} ptr idx val mem)
(MOVWstoreconstidx1 [c] {sym} ptr (SHLLconst [1] idx) mem) -> (MOVWstoreconstidx2 [c] {sym} ptr idx mem)
(MOVLstoreconstidx1 [c] {sym} ptr (SHLLconst [2] idx) mem) -> (MOVLstoreconstidx4 [c] {sym} ptr idx mem)

// combine ADDL into indexed loads and stores
(MOVBloadidx1 [c] {sym} (ADDLconst [d] ptr) idx mem) -> (MOVBloadidx1 [int64(int32(c+d))] {sym} ptr idx mem)
(MOVWloadidx1 [c] {sym} (ADDLconst [d] ptr) idx mem) -> (MOVWloadidx1 [int64(int32(c+d))] {sym} ptr idx mem)
(MOVWloadidx2 [c] {sym} (ADDLconst [d] ptr) idx mem) -> (MOVWloadidx2 [int64(int32(c+d))] {sym} ptr idx mem)
(MOVLloadidx1 [c] {sym} (ADDLconst [d] ptr) idx mem) -> (MOVLloadidx1 [int64(int32(c+d))] {sym} ptr idx mem)
(MOVLloadidx4 [c] {sym} (ADDLconst [d] ptr) idx mem) -> (MOVLloadidx4 [int64(int32(c+d))] {sym} ptr idx mem)
(MOVSSloadidx1 [c] {sym} (ADDLconst [d] ptr) idx mem) -> (MOVSSloadidx1 [int64(int32(c+d))] {sym} ptr idx mem)
(MOVSSloadidx4 [c] {sym} (ADDLconst [d] ptr) idx mem) -> (MOVSSloadidx4 [int64(int32(c+d))] {sym} ptr idx mem)
(MOVSDloadidx1 [c] {sym} (ADDLconst [d] ptr) idx mem) -> (MOVSDloadidx1 [int64(int32(c+d))] {sym} ptr idx mem)
(MOVSDloadidx8 [c] {sym} (ADDLconst [d] ptr) idx mem) -> (MOVSDloadidx8 [int64(int32(c+d))] {sym} ptr idx mem)

(MOVBstoreidx1 [c] {sym} (ADDLconst [d] ptr) idx val mem)  -> (MOVBstoreidx1 [int64(int32(c+d))] {sym} ptr idx val mem)
(MOVWstoreidx1 [c] {sym} (ADDLconst [d] ptr) idx val mem)  -> (MOVWstoreidx1 [int64(int32(c+d))] {sym} ptr idx val mem)
(MOVWstoreidx2 [c] {sym} (ADDLconst [d] ptr) idx val mem)  -> (MOVWstoreidx2 [int64(int32(c+d))] {sym} ptr idx val mem)
(MOVLstoreidx1 [c] {sym} (ADDLconst [d] ptr) idx val mem)  -> (MOVLstoreidx1 [int64(int32(c+d))] {sym} ptr idx val mem)
(MOVLstoreidx4 [c] {sym} (ADDLconst [d] ptr) idx val mem)  -> (MOVLstoreidx4 [int64(int32(c+d))] {sym} ptr idx val mem)
(MOVSSstoreidx1 [c] {sym} (ADDLconst [d] ptr) idx val mem)  -> (MOVSSstoreidx1 [int64(int32(c+d))] {sym} ptr idx val mem)
(MOVSSstoreidx4 [c] {sym} (ADDLconst [d] ptr) idx val mem)  -> (MOVSSstoreidx4 [int64(int32(c+d))] {sym} ptr idx val mem)
(MOVSDstoreidx1 [c] {sym} (ADDLconst [d] ptr) idx val mem)  -> (MOVSDstoreidx1 [int64(int32(c+d))] {sym} ptr idx val mem)
(MOVSDstoreidx8 [c] {sym} (ADDLconst [d] ptr) idx val mem)  -> (MOVSDstoreidx8 [int64(int32(c+d))] {sym} ptr idx val mem)

(MOVBloadidx1 [c] {sym} ptr (ADDLconst [d] idx) mem) -> (MOVBloadidx1  [int64(int32(c+d))]   {sym} ptr idx mem)
(MOVWloadidx1 [c] {sym} ptr (ADDLconst [d] idx) mem) -> (MOVWloadidx1  [int64(int32(c+d))]   {sym} ptr idx mem)
(MOVWloadidx2 [c] {sym} ptr (ADDLconst [d] idx) mem) -> (MOVWloadidx2  [int64(int32(c+2*d))] {sym} ptr idx mem)
(MOVLloadidx1 [c] {sym} ptr (ADDLconst [d] idx) mem) -> (MOVLloadidx1  [int64(int32(c+d))]   {sym} ptr idx mem)
(MOVLloadidx4 [c] {sym} ptr (ADDLconst [d] idx) mem) -> (MOVLloadidx4  [int64(int32(c+4*d))] {sym} ptr idx mem)
(MOVSSloadidx1 [c] {sym} ptr (ADDLconst [d] idx) mem) -> (MOVSSloadidx1 [int64(int32(c+d))]   {sym} ptr idx mem)
(MOVSSloadidx4 [c] {sym} ptr (ADDLconst [d] idx) mem) -> (MOVSSloadidx4 [int64(int32(c+4*d))] {sym} ptr idx mem)
(MOVSDloadidx1 [c] {sym} ptr (ADDLconst [d] idx) mem) -> (MOVSDloadidx1 [int64(int32(c+d))]   {sym} ptr idx mem)
(MOVSDloadidx8 [c] {sym} ptr (ADDLconst [d] idx) mem) -> (MOVSDloadidx8 [int64(int32(c+8*d))] {sym} ptr idx mem)

(MOVBstoreidx1 [c] {sym} ptr (ADDLconst [d] idx) val mem) -> (MOVBstoreidx1  [int64(int32(c+d))]   {sym} ptr idx val mem)
(MOVWstoreidx1 [c] {sym} ptr (ADDLconst [d] idx) val mem) -> (MOVWstoreidx1  [int64(int32(c+d))]   {sym} ptr idx val mem)
(MOVWstoreidx2 [c] {sym} ptr (ADDLconst [d] idx) val mem) -> (MOVWstoreidx2  [int64(int32(c+2*d))] {sym} ptr idx val mem)
(MOVLstoreidx1 [c] {sym} ptr (ADDLconst [d] idx) val mem) -> (MOVLstoreidx1  [int64(int32(c+d))]   {sym} ptr idx val mem)
(MOVLstoreidx4 [c] {sym} ptr (ADDLconst [d] idx) val mem)  -> (MOVLstoreidx4  [int64(int32(c+4*d))] {sym} ptr idx val mem)
(MOVSSstoreidx1 [c] {sym} ptr (ADDLconst [d] idx) val mem) -> (MOVSSstoreidx1 [int64(int32(c+d))]   {sym} ptr idx val mem)
(MOVSSstoreidx4 [c] {sym} ptr (ADDLconst [d] idx) val mem) -> (MOVSSstoreidx4 [int64(int32(c+4*d))] {sym} ptr idx val mem)
(MOVSDstoreidx1 [c] {sym} ptr (ADDLconst [d] idx) val mem) -> (MOVSDstoreidx1 [int64(int32(c+d))]   {sym} ptr idx val mem)
(MOVSDstoreidx8 [c] {sym} ptr (ADDLconst [d] idx) val mem) -> (MOVSDstoreidx8 [int64(int32(c+8*d))] {sym} ptr idx val mem)

(MOVBstoreconstidx1 [x] {sym} (ADDLconst [c] ptr) idx mem) ->
	(MOVBstoreconstidx1 [ValAndOff(x).add(c)] {sym} ptr idx mem)
(MOVWstoreconstidx1 [x] {sym} (ADDLconst [c] ptr) idx mem) ->
	(MOVWstoreconstidx1 [ValAndOff(x).add(c)] {sym} ptr idx mem)
(MOVWstoreconstidx2 [x] {sym} (ADDLconst [c] ptr) idx mem) ->
	(MOVWstoreconstidx2 [ValAndOff(x).add(c)] {sym} ptr idx mem)
(MOVLstoreconstidx1 [x] {sym} (ADDLconst [c] ptr) idx mem) ->
	(MOVLstoreconstidx1 [ValAndOff(x).add(c)] {sym} ptr idx mem)
(MOVLstoreconstidx4 [x] {sym} (ADDLconst [c] ptr) idx mem) ->
	(MOVLstoreconstidx4 [ValAndOff(x).add(c)] {sym} ptr idx mem)

(MOVBstoreconstidx1 [x] {sym} ptr (ADDLconst [c] idx) mem) ->
	(MOVBstoreconstidx1 [ValAndOff(x).add(c)] {sym} ptr idx mem)
(MOVWstoreconstidx1 [x] {sym} ptr (ADDLconst [c] idx) mem) ->
	(MOVWstoreconstidx1 [ValAndOff(x).add(c)] {sym} ptr idx mem)
(MOVWstoreconstidx2 [x] {sym} ptr (ADDLconst [c] idx) mem) ->
	(MOVWstoreconstidx2 [ValAndOff(x).add(2*c)] {sym} ptr idx mem)
(MOVLstoreconstidx1 [x] {sym} ptr (ADDLconst [c] idx) mem) ->
	(MOVLstoreconstidx1 [ValAndOff(x).add(c)] {sym} ptr idx mem)
(MOVLstoreconstidx4 [x] {sym} ptr (ADDLconst [c] idx) mem) ->
	(MOVLstoreconstidx4 [ValAndOff(x).add(4*c)] {sym} ptr idx mem)

// fold LEALs together
(LEAL [off1] {sym1} (LEAL [off2] {sym2} x)) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
      (LEAL [off1+off2] {mergeSym(sym1,sym2)} x)

// LEAL into LEAL1
(LEAL1 [off1] {sym1} (LEAL [off2] {sym2} x) y) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) && x.Op != OpSB ->
       (LEAL1 [off1+off2] {mergeSym(sym1,sym2)} x y)

// LEAL1 into LEAL
(LEAL [off1] {sym1} (LEAL1 [off2] {sym2} x y)) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
       (LEAL1 [off1+off2] {mergeSym(sym1,sym2)} x y)

// LEAL into LEAL[248]
(LEAL2 [off1] {sym1} (LEAL [off2] {sym2} x) y) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) && x.Op != OpSB ->
       (LEAL2 [off1+off2] {mergeSym(sym1,sym2)} x y)
(LEAL4 [off1] {sym1} (LEAL [off2] {sym2} x) y) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) && x.Op != OpSB ->
       (LEAL4 [off1+off2] {mergeSym(sym1,sym2)} x y)
(LEAL8 [off1] {sym1} (LEAL [off2] {sym2} x) y) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) && x.Op != OpSB ->
       (LEAL8 [off1+off2] {mergeSym(sym1,sym2)} x y)

// LEAL[248] into LEAL
(LEAL [off1] {sym1} (LEAL2 [off2] {sym2} x y)) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
      (LEAL2 [off1+off2] {mergeSym(sym1,sym2)} x y)
(LEAL [off1] {sym1} (LEAL4 [off2] {sym2} x y)) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
      (LEAL4 [off1+off2] {mergeSym(sym1,sym2)} x y)
(LEAL [off1] {sym1} (LEAL8 [off2] {sym2} x y)) && is32Bit(off1+off2) && canMergeSym(sym1, sym2) ->
      (LEAL8 [off1+off2] {mergeSym(sym1,sym2)} x y)

// Absorb InvertFlags into branches.
(LT (InvertFlags cmp) yes no) -> (GT cmp yes no)
(GT (InvertFlags cmp) yes no) -> (LT cmp yes no)
(LE (InvertFlags cmp) yes no) -> (GE cmp yes no)
(GE (InvertFlags cmp) yes no) -> (LE cmp yes no)
(ULT (InvertFlags cmp) yes no) -> (UGT cmp yes no)
(UGT (InvertFlags cmp) yes no) -> (ULT cmp yes no)
(ULE (InvertFlags cmp) yes no) -> (UGE cmp yes no)
(UGE (InvertFlags cmp) yes no) -> (ULE cmp yes no)
(EQ (InvertFlags cmp) yes no) -> (EQ cmp yes no)
(NE (InvertFlags cmp) yes no) -> (NE cmp yes no)

// Constant comparisons.
(CMPLconst (MOVLconst [x]) [y]) && int32(x)==int32(y) -> (FlagEQ)
(CMPLconst (MOVLconst [x]) [y]) && int32(x)<int32(y) && uint32(x)<uint32(y) -> (FlagLT_ULT)
(CMPLconst (MOVLconst [x]) [y]) && int32(x)<int32(y) && uint32(x)>uint32(y) -> (FlagLT_UGT)
(CMPLconst (MOVLconst [x]) [y]) && int32(x)>int32(y) && uint32(x)<uint32(y) -> (FlagGT_ULT)
(CMPLconst (MOVLconst [x]) [y]) && int32(x)>int32(y) && uint32(x)>uint32(y) -> (FlagGT_UGT)
(CMPWconst (MOVLconst [x]) [y]) && int16(x)==int16(y) -> (FlagEQ)
(CMPWconst (MOVLconst [x]) [y]) && int16(x)<int16(y) && uint16(x)<uint16(y) -> (FlagLT_ULT)
(CMPWconst (MOVLconst [x]) [y]) && int16(x)<int16(y) && uint16(x)>uint16(y) -> (FlagLT_UGT)
(CMPWconst (MOVLconst [x]) [y]) && int16(x)>int16(y) && uint16(x)<uint16(y) -> (FlagGT_ULT)
(CMPWconst (MOVLconst [x]) [y]) && int16(x)>int16(y) && uint16(x)>uint16(y) -> (FlagGT_UGT)
(CMPBconst (MOVLconst [x]) [y]) && int8(x)==int8(y) -> (FlagEQ)
(CMPBconst (MOVLconst [x]) [y]) && int8(x)<int8(y) && uint8(x)<uint8(y) -> (FlagLT_ULT)
(CMPBconst (MOVLconst [x]) [y]) && int8(x)<int8(y) && uint8(x)>uint8(y) -> (FlagLT_UGT)
(CMPBconst (MOVLconst [x]) [y]) && int8(x)>int8(y) && uint8(x)<uint8(y) -> (FlagGT_ULT)
(CMPBconst (MOVLconst [x]) [y]) && int8(x)>int8(y) && uint8(x)>uint8(y) -> (FlagGT_UGT)

// Other known comparisons.
(CMPLconst (SHRLconst _ [c]) [n]) && 0 <= n && 0 < c && c <= 32 && (1<<uint64(32-c)) <= uint64(n) -> (FlagLT_ULT)
(CMPLconst (ANDLconst _ [m]) [n]) && 0 <= int32(m) && int32(m) < int32(n) -> (FlagLT_ULT)
(CMPWconst (ANDLconst _ [m]) [n]) && 0 <= int16(m) && int16(m) < int16(n) -> (FlagLT_ULT)
(CMPBconst (ANDLconst _ [m]) [n]) && 0 <= int8(m) && int8(m) < int8(n) -> (FlagLT_ULT)
// TODO: DIVxU also.

// Absorb flag constants into SBB ops.
(SBBLcarrymask (FlagEQ)) -> (MOVLconst [0])
(SBBLcarrymask (FlagLT_ULT)) -> (MOVLconst [-1])
(SBBLcarrymask (FlagLT_UGT)) -> (MOVLconst [0])
(SBBLcarrymask (FlagGT_ULT)) -> (MOVLconst [-1])
(SBBLcarrymask (FlagGT_UGT)) -> (MOVLconst [0])

// Absorb flag constants into branches.
(EQ (FlagEQ) yes no) -> (First nil yes no)
(EQ (FlagLT_ULT) yes no) -> (First nil no yes)
(EQ (FlagLT_UGT) yes no) -> (First nil no yes)
(EQ (FlagGT_ULT) yes no) -> (First nil no yes)
(EQ (FlagGT_UGT) yes no) -> (First nil no yes)

(NE (FlagEQ) yes no) -> (First nil no yes)
(NE (FlagLT_ULT) yes no) -> (First nil yes no)
(NE (FlagLT_UGT) yes no) -> (First nil yes no)
(NE (FlagGT_ULT) yes no) -> (First nil yes no)
(NE (FlagGT_UGT) yes no) -> (First nil yes no)

(LT (FlagEQ) yes no) -> (First nil no yes)
(LT (FlagLT_ULT) yes no) -> (First nil yes no)
(LT (FlagLT_UGT) yes no) -> (First nil yes no)
(LT (FlagGT_ULT) yes no) -> (First nil no yes)
(LT (FlagGT_UGT) yes no) -> (First nil no yes)

(LE (FlagEQ) yes no) -> (First nil yes no)
(LE (FlagLT_ULT) yes no) -> (First nil yes no)
(LE (FlagLT_UGT) yes no) -> (First nil yes no)
(LE (FlagGT_ULT) yes no) -> (First nil no yes)
(LE (FlagGT_UGT) yes no) -> (First nil no yes)

(GT (FlagEQ) yes no) -> (First nil no yes)
(GT (FlagLT_ULT) yes no) -> (First nil no yes)
(GT (FlagLT_UGT) yes no) -> (First nil no yes)
(GT (FlagGT_ULT) yes no) -> (First nil yes no)
(GT (FlagGT_UGT) yes no) -> (First nil yes no)

(GE (FlagEQ) yes no) -> (First nil yes no)
(GE (FlagLT_ULT) yes no) -> (First nil no yes)
(GE (FlagLT_UGT) yes no) -> (First nil no yes)
(GE (FlagGT_ULT) yes no) -> (First nil yes no)
(GE (FlagGT_UGT) yes no) -> (First nil yes no)

(ULT (FlagEQ) yes no) -> (First nil no yes)
(ULT (FlagLT_ULT) yes no) -> (First nil yes no)
(ULT (FlagLT_UGT) yes no) -> (First nil no yes)
(ULT (FlagGT_ULT) yes no) -> (First nil yes no)
(ULT (FlagGT_UGT) yes no) -> (First nil no yes)

(ULE (FlagEQ) yes no) -> (First nil yes no)
(ULE (FlagLT_ULT) yes no) -> (First nil yes no)
(ULE (FlagLT_UGT) yes no) -> (First nil no yes)
(ULE (FlagGT_ULT) yes no) -> (First nil yes no)
(ULE (FlagGT_UGT) yes no) -> (First nil no yes)

(UGT (FlagEQ) yes no) -> (First nil no yes)
(UGT (FlagLT_ULT) yes no) -> (First nil no yes)
(UGT (FlagLT_UGT) yes no) -> (First nil yes no)
(UGT (FlagGT_ULT) yes no) -> (First nil no yes)
(UGT (FlagGT_UGT) yes no) -> (First nil yes no)

(UGE (FlagEQ) yes no) -> (First nil yes no)
(UGE (FlagLT_ULT) yes no) -> (First nil no yes)
(UGE (FlagLT_UGT) yes no) -> (First nil yes no)
(UGE (FlagGT_ULT) yes no) -> (First nil no yes)
(UGE (FlagGT_UGT) yes no) -> (First nil yes no)

// Absorb flag constants into SETxx ops.
(SETEQ (FlagEQ)) -> (MOVLconst [1])
(SETEQ (FlagLT_ULT)) -> (MOVLconst [0])
(SETEQ (FlagLT_UGT)) -> (MOVLconst [0])
(SETEQ (FlagGT_ULT)) -> (MOVLconst [0])
(SETEQ (FlagGT_UGT)) -> (MOVLconst [0])

(SETNE (FlagEQ)) -> (MOVLconst [0])
(SETNE (FlagLT_ULT)) -> (MOVLconst [1])
(SETNE (FlagLT_UGT)) -> (MOVLconst [1])
(SETNE (FlagGT_ULT)) -> (MOVLconst [1])
(SETNE (FlagGT_UGT)) -> (MOVLconst [1])

(SETL (FlagEQ)) -> (MOVLconst [0])
(SETL (FlagLT_ULT)) -> (MOVLconst [1])
(SETL (FlagLT_UGT)) -> (MOVLconst [1])
(SETL (FlagGT_ULT)) -> (MOVLconst [0])
(SETL (FlagGT_UGT)) -> (MOVLconst [0])

(SETLE (FlagEQ)) -> (MOVLconst [1])
(SETLE (FlagLT_ULT)) -> (MOVLconst [1])
(SETLE (FlagLT_UGT)) -> (MOVLconst [1])
(SETLE (FlagGT_ULT)) -> (MOVLconst [0])
(SETLE (FlagGT_UGT)) -> (MOVLconst [0])

(SETG (FlagEQ)) -> (MOVLconst [0])
(SETG (FlagLT_ULT)) -> (MOVLconst [0])
(SETG (FlagLT_UGT)) -> (MOVLconst [0])
(SETG (FlagGT_ULT)) -> (MOVLconst [1])
(SETG (FlagGT_UGT)) -> (MOVLconst [1])

(SETGE (FlagEQ)) -> (MOVLconst [1])
(SETGE (FlagLT_ULT)) -> (MOVLconst [0])
(SETGE (FlagLT_UGT)) -> (MOVLconst [0])
(SETGE (FlagGT_ULT)) -> (MOVLconst [1])
(SETGE (FlagGT_UGT)) -> (MOVLconst [1])

(SETB (FlagEQ)) -> (MOVLconst [0])
(SETB (FlagLT_ULT)) -> (MOVLconst [1])
(SETB (FlagLT_UGT)) -> (MOVLconst [0])
(SETB (FlagGT_ULT)) -> (MOVLconst [1])
(SETB (FlagGT_UGT)) -> (MOVLconst [0])

(SETBE (FlagEQ)) -> (MOVLconst [1])
(SETBE (FlagLT_ULT)) -> (MOVLconst [1])
(SETBE (FlagLT_UGT)) -> (MOVLconst [0])
(SETBE (FlagGT_ULT)) -> (MOVLconst [1])
(SETBE (FlagGT_UGT)) -> (MOVLconst [0])

(SETA (FlagEQ)) -> (MOVLconst [0])
(SETA (FlagLT_ULT)) -> (MOVLconst [0])
(SETA (FlagLT_UGT)) -> (MOVLconst [1])
(SETA (FlagGT_ULT)) -> (MOVLconst [0])
(SETA (FlagGT_UGT)) -> (MOVLconst [1])

(SETAE (FlagEQ)) -> (MOVLconst [1])
(SETAE (FlagLT_ULT)) -> (MOVLconst [0])
(SETAE (FlagLT_UGT)) -> (MOVLconst [1])
(SETAE (FlagGT_ULT)) -> (MOVLconst [0])
(SETAE (FlagGT_UGT)) -> (MOVLconst [1])

// Remove redundant *const ops
(ADDLconst [c] x) && int32(c)==0 -> x
(SUBLconst [c] x) && int32(c) == 0 -> x
(ANDLconst [c] _) && int32(c)==0  -> (MOVLconst [0])
(ANDLconst [c] x) && int32(c)==-1 -> x
(ORLconst [c] x) && int32(c)==0   -> x
(ORLconst [c] _) && int32(c)==-1  -> (MOVLconst [-1])
(XORLconst [c] x) && int32(c)==0   -> x
// TODO: since we got rid of the W/B versions, we might miss
// things like (ANDLconst [0x100] x) which were formerly
// (ANDBconst [0] x).  Probably doesn't happen very often.
// If we cared, we might do:
//  (ANDLconst <t> [c] x) && t.Size()==1 && int8(x)==0 -> (MOVLconst [0])

// Convert constant subtracts to constant adds
(SUBLconst [c] x) -> (ADDLconst [int64(int32(-c))] x)

// generic constant folding
// TODO: more of this
(ADDLconst [c] (MOVLconst [d])) -> (MOVLconst [int64(int32(c+d))])
(ADDLconst [c] (ADDLconst [d] x)) -> (ADDLconst [int64(int32(c+d))] x)
(SARLconst [c] (MOVLconst [d])) -> (MOVLconst [d>>uint64(c)])
(SARWconst [c] (MOVLconst [d])) -> (MOVLconst [d>>uint64(c)])
(SARBconst [c] (MOVLconst [d])) -> (MOVLconst [d>>uint64(c)])
(NEGL (MOVLconst [c])) -> (MOVLconst [int64(int32(-c))])
(MULLconst [c] (MOVLconst [d])) -> (MOVLconst [int64(int32(c*d))])
(ANDLconst [c] (MOVLconst [d])) -> (MOVLconst [c&d])
(ORLconst [c] (MOVLconst [d])) -> (MOVLconst [c|d])
(XORLconst [c] (MOVLconst [d])) -> (MOVLconst [c^d])
(NOTL (MOVLconst [c])) -> (MOVLconst [^c])

// generic simplifications
// TODO: more of this
(ADDL x (NEGL y)) -> (SUBL x y)
(SUBL x x) -> (MOVLconst [0])
(ANDL x x) -> x
(ORL x x) -> x
(XORL x x) -> (MOVLconst [0])

// checking AND against 0.
(CMP(L|W|B)const (ANDL x y) [0]) -> (TEST(L|W|B) x y)
(CMPLconst (ANDLconst [c] x) [0]) -> (TESTLconst [c] x)
(CMPWconst (ANDLconst [c] x) [0]) -> (TESTWconst [int64(int16(c))] x)
(CMPBconst (ANDLconst [c] x) [0]) -> (TESTBconst [int64(int8(c))] x)

// TEST %reg,%reg is shorter than CMP
(CMP(L|W|B)const x [0]) -> (TEST(L|W|B) x x)

// Combining byte loads into larger (unaligned) loads.
// There are many ways these combinations could occur.  This is
// designed to match the way encoding/binary.LittleEndian does it.
(ORL                  x0:(MOVBload [i0] {s} p mem)
    s0:(SHLLconst [8] x1:(MOVBload [i1] {s} p mem)))
  && i1 == i0+1
  && x0.Uses == 1
  && x1.Uses == 1
  && s0.Uses == 1
  && mergePoint(b,x0,x1) != nil
  && clobber(x0)
  && clobber(x1)
  && clobber(s0)
  -> @mergePoint(b,x0,x1) (MOVWload [i0] {s} p mem)

(ORL o0:(ORL
                       x0:(MOVWload [i0] {s} p mem)
    s0:(SHLLconst [16] x1:(MOVBload [i2] {s} p mem)))
    s1:(SHLLconst [24] x2:(MOVBload [i3] {s} p mem)))
  && i2 == i0+2
  && i3 == i0+3
  && x0.Uses == 1
  && x1.Uses == 1
  && x2.Uses == 1
  && s0.Uses == 1
  && s1.Uses == 1
  && o0.Uses == 1
  && mergePoint(b,x0,x1,x2) != nil
  && clobber(x0)
  && clobber(x1)
  && clobber(x2)
  && clobber(s0)
  && clobber(s1)
  && clobber(o0)
  -> @mergePoint(b,x0,x1,x2) (MOVLload [i0] {s} p mem)

(ORL                  x0:(MOVBloadidx1 [i0] {s} p idx mem)
    s0:(SHLLconst [8] x1:(MOVBloadidx1 [i1] {s} p idx mem)))
  && i1==i0+1
  && x0.Uses == 1
  && x1.Uses == 1
  && s0.Uses == 1
  && mergePoint(b,x0,x1) != nil
  && clobber(x0)
  && clobber(x1)
  && clobber(s0)
  -> @mergePoint(b,x0,x1) (MOVWloadidx1 <v.Type> [i0] {s} p idx mem)

(ORL o0:(ORL
                       x0:(MOVWloadidx1 [i0] {s} p idx mem)
    s0:(SHLLconst [16] x1:(MOVBloadidx1 [i2] {s} p idx mem)))
    s1:(SHLLconst [24] x2:(MOVBloadidx1 [i3] {s} p idx mem)))
  && i2 == i0+2
  && i3 == i0+3
  && x0.Uses == 1
  && x1.Uses == 1
  && x2.Uses == 1
  && s0.Uses == 1
  && s1.Uses == 1
  && o0.Uses == 1
  && mergePoint(b,x0,x1,x2) != nil
  && clobber(x0)
  && clobber(x1)
  && clobber(x2)
  && clobber(s0)
  && clobber(s1)
  && clobber(o0)
  -> @mergePoint(b,x0,x1,x2) (MOVLloadidx1 <v.Type> [i0] {s} p idx mem)

// Combine constant stores into larger (unaligned) stores.
(MOVBstoreconst [c] {s} p x:(MOVBstoreconst [a] {s} p mem))
  && x.Uses == 1
  && ValAndOff(a).Off() + 1 == ValAndOff(c).Off()
  && clobber(x)
  -> (MOVWstoreconst [makeValAndOff(ValAndOff(a).Val()&0xff | ValAndOff(c).Val()<<8, ValAndOff(a).Off())] {s} p mem)
(MOVWstoreconst [c] {s} p x:(MOVWstoreconst [a] {s} p mem))
  && x.Uses == 1
  && ValAndOff(a).Off() + 2 == ValAndOff(c).Off()
  && clobber(x)
  -> (MOVLstoreconst [makeValAndOff(ValAndOff(a).Val()&0xffff | ValAndOff(c).Val()<<16, ValAndOff(a).Off())] {s} p mem)

(MOVBstoreconstidx1 [c] {s} p i x:(MOVBstoreconstidx1 [a] {s} p i mem))
  && x.Uses == 1
  && ValAndOff(a).Off() + 1 == ValAndOff(c).Off()
  && clobber(x)
  -> (MOVWstoreconstidx1 [makeValAndOff(ValAndOff(a).Val()&0xff | ValAndOff(c).Val()<<8, ValAndOff(a).Off())] {s} p i mem)
(MOVWstoreconstidx1 [c] {s} p i x:(MOVWstoreconstidx1 [a] {s} p i mem))
  && x.Uses == 1
  && ValAndOff(a).Off() + 2 == ValAndOff(c).Off()
  && clobber(x)
  -> (MOVLstoreconstidx1 [makeValAndOff(ValAndOff(a).Val()&0xffff | ValAndOff(c).Val()<<16, ValAndOff(a).Off())] {s} p i mem)

(MOVWstoreconstidx2 [c] {s} p i x:(MOVWstoreconstidx2 [a] {s} p i mem))
  && x.Uses == 1
  && ValAndOff(a).Off() + 2 == ValAndOff(c).Off()
  && clobber(x)
  -> (MOVLstoreconstidx1 [makeValAndOff(ValAndOff(a).Val()&0xffff | ValAndOff(c).Val()<<16, ValAndOff(a).Off())] {s} p (SHLLconst <i.Type> [1] i) mem)

// Combine stores into larger (unaligned) stores.
(MOVBstore [i] {s} p (SHRLconst [8] w) x:(MOVBstore [i-1] {s} p w mem))
  && x.Uses == 1
  && clobber(x)
  -> (MOVWstore [i-1] {s} p w mem)
(MOVBstore [i] {s} p (SHRLconst [j] w) x:(MOVBstore [i-1] {s} p w0:(SHRLconst [j-8] w) mem))
  && x.Uses == 1
  && clobber(x)
  -> (MOVWstore [i-1] {s} p w0 mem)
(MOVWstore [i] {s} p (SHRLconst [16] w) x:(MOVWstore [i-2] {s} p w mem))
  && x.Uses == 1
  && clobber(x)
  -> (MOVLstore [i-2] {s} p w mem)
(MOVWstore [i] {s} p (SHRLconst [j] w) x:(MOVWstore [i-2] {s} p w0:(SHRLconst [j-16] w) mem))
  && x.Uses == 1
  && clobber(x)
  -> (MOVLstore [i-2] {s} p w0 mem)

(MOVBstoreidx1 [i] {s} p idx (SHRLconst [8] w) x:(MOVBstoreidx1 [i-1] {s} p idx w mem))
  && x.Uses == 1
  && clobber(x)
  -> (MOVWstoreidx1 [i-1] {s} p idx w mem)
(MOVBstoreidx1 [i] {s} p idx (SHRLconst [j] w) x:(MOVBstoreidx1 [i-1] {s} p idx w0:(SHRLconst [j-8] w) mem))
  && x.Uses == 1
  && clobber(x)
  -> (MOVWstoreidx1 [i-1] {s} p idx w0 mem)
(MOVWstoreidx1 [i] {s} p idx (SHRLconst [16] w) x:(MOVWstoreidx1 [i-2] {s} p idx w mem))
  && x.Uses == 1
  && clobber(x)
  -> (MOVLstoreidx1 [i-2] {s} p idx w mem)
(MOVWstoreidx1 [i] {s} p idx (SHRLconst [j] w) x:(MOVWstoreidx1 [i-2] {s} p idx w0:(SHRLconst [j-16] w) mem))
  && x.Uses == 1
  && clobber(x)
  -> (MOVLstoreidx1 [i-2] {s} p idx w0 mem)

(MOVWstoreidx2 [i] {s} p idx (SHRLconst [16] w) x:(MOVWstoreidx2 [i-2] {s} p idx w mem))
  && x.Uses == 1
  && clobber(x)
  -> (MOVLstoreidx1 [i-2] {s} p (SHLLconst <idx.Type> [1] idx) w mem)
(MOVWstoreidx2 [i] {s} p idx (SHRLconst [j] w) x:(MOVWstoreidx2 [i-2] {s} p idx w0:(SHRLconst [j-16] w) mem))
  && x.Uses == 1
  && clobber(x)
  -> (MOVLstoreidx1 [i-2] {s} p (SHLLconst <idx.Type> [1] idx) w0 mem)

// For PIC, break floating-point constant loading into two instructions so we have
// a register to use for holding the address of the constant pool entry.
(MOVSSconst [c]) && config.ctxt.Flag_shared -> (MOVSSconst2 (MOVSSconst1 [c]))
(MOVSDconst [c]) && config.ctxt.Flag_shared -> (MOVSDconst2 (MOVSDconst1 [c]))