github.com/gagliardetto/golang-go@v0.0.0-20201020153340-53909ea70814/cmd/compile/internal/ssa/gen/MIPS.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.

(Add(Ptr|32|16|8) x y) -> (ADD x y)
(Add(32|64)F x y) -> (ADD(F|D) x y)

(Select0 (Add32carry <t> x y)) -> (ADD <t.FieldType(0)> x y)
(Select1 (Add32carry <t> x y)) -> (SGTU <typ.Bool> x (ADD <t.FieldType(0)> x y))
(Add32withcarry <t> x y c) -> (ADD c (ADD <t> x y))

(Sub(Ptr|32|16|8) x y) -> (SUB x y)
(Sub(32|64)F x y) -> (SUB(F|D) x y)

(Select0 (Sub32carry <t> x y)) -> (SUB <t.FieldType(0)> x y)
(Select1 (Sub32carry <t> x y)) -> (SGTU <typ.Bool> (SUB <t.FieldType(0)> x y) x)
(Sub32withcarry <t> x y c) -> (SUB (SUB <t> x y) c)

(Mul(32|16|8) x y) -> (MUL x y)
(Mul(32|64)F x y) -> (MUL(F|D) x y)

(Hmul(32|32u) x y) -> (Select0 (MUL(T|TU) x y))
(Mul32uhilo x y) -> (MULTU x y)

(Div32 x y) -> (Select1 (DIV x y))
(Div32u x y) -> (Select1 (DIVU x y))
(Div16 x y) -> (Select1 (DIV (SignExt16to32 x) (SignExt16to32 y)))
(Div16u x y) -> (Select1 (DIVU (ZeroExt16to32 x) (ZeroExt16to32 y)))
(Div8 x y) -> (Select1 (DIV (SignExt8to32 x) (SignExt8to32 y)))
(Div8u x y) -> (Select1 (DIVU (ZeroExt8to32 x) (ZeroExt8to32 y)))
(Div(32|64)F x y) -> (DIV(F|D) x y)

(Mod32 x y) -> (Select0 (DIV x y))
(Mod32u x y) -> (Select0 (DIVU x y))
(Mod16 x y) -> (Select0 (DIV (SignExt16to32 x) (SignExt16to32 y)))
(Mod16u x y) -> (Select0 (DIVU (ZeroExt16to32 x) (ZeroExt16to32 y)))
(Mod8 x y) -> (Select0 (DIV (SignExt8to32 x) (SignExt8to32 y)))
(Mod8u x y) -> (Select0 (DIVU (ZeroExt8to32 x) (ZeroExt8to32 y)))

// (x + y) / 2 with x>=y -> (x - y) / 2 + y
(Avg32u <t> x y) -> (ADD (SRLconst <t> (SUB <t> x y) [1]) y)

(And(32|16|8) x y) -> (AND x y)
(Or(32|16|8) x y) -> (OR x y)
(Xor(32|16|8) x y) -> (XOR x y)

// constant shifts
// generic opt rewrites all constant shifts to shift by Const64
(Lsh32x64 x (Const64 [c])) && uint32(c) < 32 -> (SLLconst x [c])
(Rsh32x64 x (Const64 [c])) && uint32(c) < 32 -> (SRAconst x [c])
(Rsh32Ux64 x (Const64 [c])) && uint32(c) < 32 -> (SRLconst x [c])
(Lsh16x64 x (Const64 [c])) && uint32(c) < 16 -> (SLLconst x [c])
(Rsh16x64 x (Const64 [c])) && uint32(c) < 16 -> (SRAconst (SLLconst <typ.UInt32> x [16]) [c+16])
(Rsh16Ux64 x (Const64 [c])) && uint32(c) < 16 -> (SRLconst (SLLconst <typ.UInt32> x [16]) [c+16])
(Lsh8x64 x (Const64 [c])) && uint32(c) < 8 -> (SLLconst x [c])
(Rsh8x64 x (Const64 [c])) && uint32(c) < 8 -> (SRAconst (SLLconst <typ.UInt32> x [24]) [c+24])
(Rsh8Ux64 x (Const64 [c])) && uint32(c) < 8 -> (SRLconst (SLLconst <typ.UInt32> x [24]) [c+24])

// large constant shifts
(Lsh32x64 _ (Const64 [c])) && uint32(c) >= 32 -> (MOVWconst [0])
(Rsh32Ux64 _ (Const64 [c])) && uint32(c) >= 32 -> (MOVWconst [0])
(Lsh16x64 _ (Const64 [c])) && uint32(c) >= 16 -> (MOVWconst [0])
(Rsh16Ux64 _ (Const64 [c])) && uint32(c) >= 16 -> (MOVWconst [0])
(Lsh8x64 _ (Const64 [c])) && uint32(c) >= 8 -> (MOVWconst [0])
(Rsh8Ux64 _ (Const64 [c])) && uint32(c) >= 8 -> (MOVWconst [0])

// large constant signed right shift, we leave the sign bit
(Rsh32x64 x (Const64 [c])) && uint32(c) >= 32 -> (SRAconst x [31])
(Rsh16x64 x (Const64 [c])) && uint32(c) >= 16 -> (SRAconst (SLLconst <typ.UInt32> x [16]) [31])
(Rsh8x64 x (Const64 [c])) && uint32(c) >= 8 -> (SRAconst (SLLconst <typ.UInt32> x [24]) [31])

// shifts
// hardware instruction uses only the low 5 bits of the shift
// we compare to 32 to ensure Go semantics for large shifts
(Lsh32x32 <t> x y) -> (CMOVZ (SLL <t> x y) (MOVWconst [0]) (SGTUconst [32] y))
(Lsh32x16 <t> x y) -> (CMOVZ (SLL <t> x (ZeroExt16to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt16to32 y)))
(Lsh32x8 <t> x y) -> (CMOVZ (SLL <t> x (ZeroExt8to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt8to32 y)))

(Lsh16x32 <t> x y) -> (CMOVZ (SLL <t> x y) (MOVWconst [0]) (SGTUconst [32] y))
(Lsh16x16 <t> x y) -> (CMOVZ (SLL <t> x (ZeroExt16to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt16to32 y)))
(Lsh16x8 <t> x y) -> (CMOVZ (SLL <t> x (ZeroExt8to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt8to32 y)))

(Lsh8x32 <t> x y) -> (CMOVZ (SLL <t> x y) (MOVWconst [0]) (SGTUconst [32] y))
(Lsh8x16 <t> x y) -> (CMOVZ (SLL <t> x (ZeroExt16to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt16to32 y)))
(Lsh8x8 <t> x y) -> (CMOVZ (SLL <t> x (ZeroExt8to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt8to32 y)))

(Rsh32Ux32 <t> x y) -> (CMOVZ (SRL <t> x y) (MOVWconst [0]) (SGTUconst [32] y))
(Rsh32Ux16 <t> x y) -> (CMOVZ (SRL <t> x (ZeroExt16to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt16to32 y)))
(Rsh32Ux8 <t> x y) -> (CMOVZ (SRL <t> x (ZeroExt8to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt8to32 y)))

(Rsh16Ux32 <t> x y) -> (CMOVZ (SRL <t> (ZeroExt16to32 x) y) (MOVWconst [0]) (SGTUconst [32] y))
(Rsh16Ux16 <t> x y) -> (CMOVZ (SRL <t> (ZeroExt16to32 x) (ZeroExt16to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt16to32 y)))
(Rsh16Ux8 <t> x y) -> (CMOVZ (SRL <t> (ZeroExt16to32 x) (ZeroExt8to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt8to32 y)))

(Rsh8Ux32 <t> x y) -> (CMOVZ (SRL <t> (ZeroExt8to32 x) y) (MOVWconst [0]) (SGTUconst [32] y))
(Rsh8Ux16 <t> x y) -> (CMOVZ (SRL <t> (ZeroExt8to32 x) (ZeroExt16to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt16to32 y)))
(Rsh8Ux8 <t> x y) -> (CMOVZ (SRL <t> (ZeroExt8to32 x) (ZeroExt8to32 y) ) (MOVWconst [0]) (SGTUconst [32] (ZeroExt8to32 y)))

(Rsh32x32 x y) -> (SRA x ( CMOVZ <typ.UInt32> y (MOVWconst [-1]) (SGTUconst [32] y)))
(Rsh32x16 x y) -> (SRA x ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt16to32 y))))
(Rsh32x8 x y) -> (SRA x ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt8to32 y))))

(Rsh16x32 x y) -> (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> y (MOVWconst [-1]) (SGTUconst [32] y)))
(Rsh16x16 x y) -> (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt16to32 y))))
(Rsh16x8 x y) -> (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt8to32 y))))

(Rsh8x32 x y) -> (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> y (MOVWconst [-1]) (SGTUconst [32] y)))
(Rsh8x16 x y) -> (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt16to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt16to32 y))))
(Rsh8x8 x y) -> (SRA (SignExt16to32 x) ( CMOVZ <typ.UInt32> (ZeroExt8to32 y) (MOVWconst [-1]) (SGTUconst [32] (ZeroExt8to32 y))))

// rotates
(RotateLeft8 <t> x (MOVWconst [c])) -> (Or8 (Lsh8x32 <t> x (MOVWconst [c&7])) (Rsh8Ux32 <t> x (MOVWconst [-c&7])))
(RotateLeft16 <t> x (MOVWconst [c])) -> (Or16 (Lsh16x32 <t> x (MOVWconst [c&15])) (Rsh16Ux32 <t> x (MOVWconst [-c&15])))
(RotateLeft32 <t> x (MOVWconst [c])) -> (Or32 (Lsh32x32 <t> x (MOVWconst [c&31])) (Rsh32Ux32 <t> x (MOVWconst [-c&31])))
(RotateLeft64 <t> x (MOVWconst [c])) -> (Or64 (Lsh64x32 <t> x (MOVWconst [c&63])) (Rsh64Ux32 <t> x (MOVWconst [-c&63])))

// unary ops
(Neg(32|16|8) x) -> (NEG x)
(Neg(32|64)F x) -> (NEG(F|D) x)

(Com(32|16|8) x) -> (NORconst [0] x)

(Sqrt x) -> (SQRTD x)

// TODO: optimize this case?
(Ctz32NonZero x) -> (Ctz32 x)

// count trailing zero
// 32 - CLZ(x&-x - 1)
(Ctz32 <t> x) -> (SUB (MOVWconst [32]) (CLZ <t> (SUBconst <t> [1] (AND <t> x (NEG <t> x)))))

// bit length
(BitLen32 <t> x) -> (SUB (MOVWconst [32]) (CLZ <t> x))

// boolean ops -- booleans are represented with 0=false, 1=true
(AndB x y) -> (AND x y)
(OrB x y) -> (OR x y)
(EqB x y) -> (XORconst [1] (XOR <typ.Bool> x y))
(NeqB x y) -> (XOR x y)
(Not x) -> (XORconst [1] x)

// constants
(Const(32|16|8) [val]) -> (MOVWconst [val])
(Const(32|64)F [val]) -> (MOV(F|D)const [val])
(ConstNil) -> (MOVWconst [0])
(ConstBool [b]) -> (MOVWconst [b])

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

// Zero-/Sign-extensions
(ZeroExt8to16 x) -> (MOVBUreg x)
(ZeroExt8to32 x) -> (MOVBUreg x)
(ZeroExt16to32 x) -> (MOVHUreg x)

(SignExt8to16 x) -> (MOVBreg x)
(SignExt8to32 x) -> (MOVBreg x)
(SignExt16to32 x) -> (MOVHreg x)

(Signmask x) -> (SRAconst x [31])
(Zeromask x) -> (NEG (SGTU x (MOVWconst [0])))
(Slicemask <t> x) -> (SRAconst (NEG <t> x) [31])

// float <-> int conversion
(Cvt32to(32|64)F x) -> (MOVW(F|D) x)
(Cvt(32|64)Fto32 x) -> (TRUNC(F|D)W x)
(Cvt32Fto64F x) -> (MOVFD x)
(Cvt64Fto32F x) -> (MOVDF x)

(Round(32|64)F x) -> x

// comparisons
(Eq8 x y)  -> (SGTUconst [1] (XOR (ZeroExt8to32 x) (ZeroExt8to32 y)))
(Eq16 x y) -> (SGTUconst [1] (XOR (ZeroExt16to32 x) (ZeroExt16to32 y)))
(Eq32 x y) -> (SGTUconst [1] (XOR x y))
(EqPtr x y) -> (SGTUconst [1] (XOR x y))
(Eq(32|64)F x y) -> (FPFlagTrue (CMPEQ(F|D) x y))

(Neq8 x y)  -> (SGTU (XOR (ZeroExt8to32 x) (ZeroExt8to32 y)) (MOVWconst [0]))
(Neq16 x y) -> (SGTU (XOR (ZeroExt16to32 x) (ZeroExt16to32 y)) (MOVWconst [0]))
(Neq32 x y) -> (SGTU (XOR x y) (MOVWconst [0]))
(NeqPtr x y) -> (SGTU (XOR x y) (MOVWconst [0]))
(Neq(32|64)F x y) -> (FPFlagFalse (CMPEQ(F|D) x y))

(Less8 x y)  -> (SGT (SignExt8to32 y) (SignExt8to32 x))
(Less16 x y) -> (SGT (SignExt16to32 y) (SignExt16to32 x))
(Less32 x y) -> (SGT y x)
(Less(32|64)F x y) -> (FPFlagTrue (CMPGT(F|D) y x)) // reverse operands to work around NaN

(Less8U x y)  -> (SGTU (ZeroExt8to32 y) (ZeroExt8to32 x))
(Less16U x y) -> (SGTU (ZeroExt16to32 y) (ZeroExt16to32 x))
(Less32U x y) -> (SGTU y x)

(Leq8 x y)  -> (XORconst [1] (SGT (SignExt8to32 x) (SignExt8to32 y)))
(Leq16 x y) -> (XORconst [1] (SGT (SignExt16to32 x) (SignExt16to32 y)))
(Leq32 x y) -> (XORconst [1] (SGT x y))
(Leq(32|64)F x y) -> (FPFlagTrue (CMPGE(F|D) y x)) // reverse operands to work around NaN

(Leq8U x y)  -> (XORconst [1] (SGTU (ZeroExt8to32 x) (ZeroExt8to32 y)))
(Leq16U x y) -> (XORconst [1] (SGTU (ZeroExt16to32 x) (ZeroExt16to32 y)))
(Leq32U x y) -> (XORconst [1] (SGTU x y))

(Greater8 x y)  -> (SGT (SignExt8to32 x) (SignExt8to32 y))
(Greater16 x y) -> (SGT (SignExt16to32 x) (SignExt16to32 y))
(Greater32 x y) -> (SGT x y)
(Greater(32|64)F x y) -> (FPFlagTrue (CMPGT(F|D) x y))

(Greater8U x y)  -> (SGTU (ZeroExt8to32 x) (ZeroExt8to32 y))
(Greater16U x y) -> (SGTU (ZeroExt16to32 x) (ZeroExt16to32 y))
(Greater32U x y) -> (SGTU x y)

(Geq8 x y)  -> (XORconst [1] (SGT (SignExt8to32 y) (SignExt8to32 x)))
(Geq16 x y) -> (XORconst [1] (SGT (SignExt16to32 y) (SignExt16to32 x)))
(Geq32 x y) -> (XORconst [1] (SGT y x))
(Geq(32|64)F x y) -> (FPFlagTrue (CMPGE(F|D) x y))

(Geq8U x y)  -> (XORconst [1] (SGTU (ZeroExt8to32 y) (ZeroExt8to32 x)))
(Geq16U x y) -> (XORconst [1] (SGTU (ZeroExt16to32 y) (ZeroExt16to32 x)))
(Geq32U x y) -> (XORconst [1] (SGTU y x))

(OffPtr [off] ptr:(SP)) -> (MOVWaddr [off] ptr)
(OffPtr [off] ptr) -> (ADDconst [off] ptr)

(Addr {sym} base) -> (MOVWaddr {sym} base)
(LocalAddr {sym} base _) -> (MOVWaddr {sym} base)

// loads
(Load <t> ptr mem) && t.IsBoolean() -> (MOVBUload ptr mem)
(Load <t> ptr mem) && (is8BitInt(t) && isSigned(t)) -> (MOVBload ptr mem)
(Load <t> ptr mem) && (is8BitInt(t) && !isSigned(t)) -> (MOVBUload ptr mem)
(Load <t> ptr mem) && (is16BitInt(t) && isSigned(t)) -> (MOVHload ptr mem)
(Load <t> ptr mem) && (is16BitInt(t) && !isSigned(t)) -> (MOVHUload ptr mem)
(Load <t> ptr mem) && (is32BitInt(t) || isPtr(t)) -> (MOVWload ptr mem)
(Load <t> ptr mem) && is32BitFloat(t) -> (MOVFload ptr mem)
(Load <t> ptr mem) && is64BitFloat(t) -> (MOVDload ptr mem)

// stores
(Store {t} ptr val mem) && t.(*types.Type).Size() == 1 -> (MOVBstore ptr val mem)
(Store {t} ptr val mem) && t.(*types.Type).Size() == 2 -> (MOVHstore ptr val mem)
(Store {t} ptr val mem) && t.(*types.Type).Size() == 4 && !is32BitFloat(val.Type) -> (MOVWstore ptr val mem)
(Store {t} ptr val mem) && t.(*types.Type).Size() == 4 && is32BitFloat(val.Type) -> (MOVFstore ptr val mem)
(Store {t} ptr val mem) && t.(*types.Type).Size() == 8 && is64BitFloat(val.Type) -> (MOVDstore ptr val mem)

// zero instructions
(Zero [0] _ mem) -> mem
(Zero [1] ptr mem) -> (MOVBstore ptr (MOVWconst [0]) mem)
(Zero [2] {t} ptr mem) && t.(*types.Type).Alignment()%2 == 0 ->
	(MOVHstore ptr (MOVWconst [0]) mem)
(Zero [2] ptr mem) ->
	(MOVBstore [1] ptr (MOVWconst [0])
		(MOVBstore [0] ptr (MOVWconst [0]) mem))
(Zero [4] {t} ptr mem) && t.(*types.Type).Alignment()%4 == 0 ->
	(MOVWstore ptr (MOVWconst [0]) mem)
(Zero [4] {t} ptr mem) && t.(*types.Type).Alignment()%2 == 0 ->
	(MOVHstore [2] ptr (MOVWconst [0])
		(MOVHstore [0] ptr (MOVWconst [0]) mem))
(Zero [4] ptr mem) ->
	(MOVBstore [3] ptr (MOVWconst [0])
		(MOVBstore [2] ptr (MOVWconst [0])
			(MOVBstore [1] ptr (MOVWconst [0])
				(MOVBstore [0] ptr (MOVWconst [0]) mem))))
(Zero [3] ptr mem) ->
	(MOVBstore [2] ptr (MOVWconst [0])
		(MOVBstore [1] ptr (MOVWconst [0])
			(MOVBstore [0] ptr (MOVWconst [0]) mem)))
(Zero [6] {t} ptr mem) && t.(*types.Type).Alignment()%2 == 0 ->
	(MOVHstore [4] ptr (MOVWconst [0])
		(MOVHstore [2] ptr (MOVWconst [0])
			(MOVHstore [0] ptr (MOVWconst [0]) mem)))
(Zero [8] {t} ptr mem) && t.(*types.Type).Alignment()%4 == 0 ->
		(MOVWstore [4] ptr (MOVWconst [0])
			(MOVWstore [0] ptr (MOVWconst [0]) mem))
(Zero [12] {t} ptr mem) && t.(*types.Type).Alignment()%4 == 0 ->
	(MOVWstore [8] ptr (MOVWconst [0])
		(MOVWstore [4] ptr (MOVWconst [0])
			(MOVWstore [0] ptr (MOVWconst [0]) mem)))
(Zero [16] {t} ptr mem) && t.(*types.Type).Alignment()%4 == 0 ->
	(MOVWstore [12] ptr (MOVWconst [0])
		(MOVWstore [8] ptr (MOVWconst [0])
			(MOVWstore [4] ptr (MOVWconst [0])
				(MOVWstore [0] ptr (MOVWconst [0]) mem))))

// large or unaligned zeroing uses a loop
(Zero [s] {t} ptr mem)
	&& (s > 16  || t.(*types.Type).Alignment()%4 != 0) ->
	(LoweredZero [t.(*types.Type).Alignment()]
		ptr
		(ADDconst <ptr.Type> ptr [s-moveSize(t.(*types.Type).Alignment(), config)])
		mem)

// moves
(Move [0] _ _ mem) -> mem
(Move [1] dst src mem) -> (MOVBstore dst (MOVBUload src mem) mem)
(Move [2] {t} dst src mem) && t.(*types.Type).Alignment()%2 == 0 ->
	(MOVHstore dst (MOVHUload src mem) mem)
(Move [2] dst src mem) ->
	(MOVBstore [1] dst (MOVBUload [1] src mem)
		(MOVBstore dst (MOVBUload src mem) mem))
(Move [4] {t} dst src mem) && t.(*types.Type).Alignment()%4 == 0 ->
	(MOVWstore dst (MOVWload src mem) mem)
(Move [4] {t} dst src mem) && t.(*types.Type).Alignment()%2 == 0 ->
	(MOVHstore [2] dst (MOVHUload [2] src mem)
		(MOVHstore dst (MOVHUload src mem) mem))
(Move [4] dst src mem) ->
	(MOVBstore [3] dst (MOVBUload [3] src mem)
		(MOVBstore [2] dst (MOVBUload [2] src mem)
			(MOVBstore [1] dst (MOVBUload [1] src mem)
				(MOVBstore dst (MOVBUload src mem) mem))))
(Move [3] dst src mem) ->
	(MOVBstore [2] dst (MOVBUload [2] src mem)
		(MOVBstore [1] dst (MOVBUload [1] src mem)
			(MOVBstore dst (MOVBUload src mem) mem)))
(Move [8] {t} dst src mem) && t.(*types.Type).Alignment()%4 == 0 ->
	(MOVWstore [4] dst (MOVWload [4] src mem)
		(MOVWstore dst (MOVWload src mem) mem))
(Move [8] {t} dst src mem) && t.(*types.Type).Alignment()%2 == 0 ->
	(MOVHstore [6] dst (MOVHload [6] src mem)
		(MOVHstore [4] dst (MOVHload [4] src mem)
			(MOVHstore [2] dst (MOVHload [2] src mem)
				(MOVHstore dst (MOVHload src mem) mem))))
(Move [6] {t} dst src mem) && t.(*types.Type).Alignment()%2 == 0 ->
	(MOVHstore [4] dst (MOVHload [4] src mem)
		(MOVHstore [2] dst (MOVHload [2] src mem)
			(MOVHstore dst (MOVHload src mem) mem)))
(Move [12] {t} dst src mem) && t.(*types.Type).Alignment()%4 == 0 ->
	(MOVWstore [8] dst (MOVWload [8] src mem)
		(MOVWstore [4] dst (MOVWload [4] src mem)
			(MOVWstore dst (MOVWload src mem) mem)))
(Move [16] {t} dst src mem) && t.(*types.Type).Alignment()%4 == 0 ->
	(MOVWstore [12] dst (MOVWload [12] src mem)
		(MOVWstore [8] dst (MOVWload [8] src mem)
			(MOVWstore [4] dst (MOVWload [4] src mem)
				(MOVWstore dst (MOVWload src mem) mem))))


// large or unaligned move uses a loop
(Move [s] {t} dst src mem)
	&& (s > 16 || t.(*types.Type).Alignment()%4 != 0) ->
	(LoweredMove [t.(*types.Type).Alignment()]
		dst
		src
		(ADDconst <src.Type> src [s-moveSize(t.(*types.Type).Alignment(), config)])
		mem)

// 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)

// atomic intrinsics
(AtomicLoad(8|32) ptr mem) -> (LoweredAtomicLoad(8|32) ptr mem)
(AtomicLoadPtr    ptr mem) -> (LoweredAtomicLoad32     ptr mem)

(AtomicStore(8|32)  ptr val mem) -> (LoweredAtomicStore(8|32) ptr val mem)
(AtomicStorePtrNoWB ptr val mem) -> (LoweredAtomicStore32     ptr val mem)

(AtomicExchange32 ptr val mem) -> (LoweredAtomicExchange ptr val mem)
(AtomicAdd32 ptr val mem) -> (LoweredAtomicAdd ptr val mem)

(AtomicCompareAndSwap32 ptr old new_ mem) -> (LoweredAtomicCas ptr old new_ mem)

// AtomicOr8(ptr,val) -> LoweredAtomicOr(ptr&^3,uint32(val) << ((ptr & 3) * 8))
(AtomicOr8 ptr val mem) && !config.BigEndian ->
	(LoweredAtomicOr (AND <typ.UInt32Ptr> (MOVWconst [^3]) ptr)
		(SLL <typ.UInt32> (ZeroExt8to32 val)
			(SLLconst <typ.UInt32> [3]
				(ANDconst <typ.UInt32> [3] ptr))) mem)

// AtomicAnd8(ptr,val) -> LoweredAtomicAnd(ptr&^3,(uint32(val) << ((ptr & 3) * 8)) | ^(uint32(0xFF) << ((ptr & 3) * 8))))
(AtomicAnd8  ptr val mem) && !config.BigEndian ->
	(LoweredAtomicAnd (AND <typ.UInt32Ptr> (MOVWconst [^3]) ptr)
		(OR <typ.UInt32> (SLL <typ.UInt32> (ZeroExt8to32 val)
			(SLLconst <typ.UInt32> [3]
				(ANDconst  <typ.UInt32> [3] ptr)))
		(NORconst [0] <typ.UInt32> (SLL <typ.UInt32>
			(MOVWconst [0xff]) (SLLconst <typ.UInt32> [3]
				(ANDconst <typ.UInt32> [3] ptr))))) mem)

// AtomicOr8(ptr,val) -> LoweredAtomicOr(ptr&^3,uint32(val) << (((ptr^3) & 3) * 8))
(AtomicOr8 ptr val mem) && config.BigEndian ->
	(LoweredAtomicOr (AND <typ.UInt32Ptr> (MOVWconst [^3]) ptr)
		(SLL <typ.UInt32> (ZeroExt8to32 val)
			(SLLconst <typ.UInt32> [3]
				(ANDconst <typ.UInt32> [3]
					(XORconst <typ.UInt32> [3] ptr)))) mem)

// AtomicAnd8(ptr,val) -> LoweredAtomicAnd(ptr&^3,(uint32(val) << (((ptr^3) & 3) * 8)) | ^(uint32(0xFF) << (((ptr^3) & 3) * 8))))
(AtomicAnd8  ptr val mem) && config.BigEndian ->
	(LoweredAtomicAnd (AND <typ.UInt32Ptr> (MOVWconst [^3]) ptr)
		(OR <typ.UInt32> (SLL <typ.UInt32> (ZeroExt8to32 val)
			(SLLconst <typ.UInt32> [3]
				(ANDconst  <typ.UInt32> [3]
					(XORconst <typ.UInt32> [3] ptr))))
		(NORconst [0] <typ.UInt32> (SLL <typ.UInt32>
			(MOVWconst [0xff]) (SLLconst <typ.UInt32> [3]
				(ANDconst <typ.UInt32> [3]
					(XORconst <typ.UInt32> [3] ptr)))))) mem)


// checks
(NilCheck ptr mem) -> (LoweredNilCheck ptr mem)
(IsNonNil ptr) -> (SGTU ptr (MOVWconst [0]))
(IsInBounds idx len) -> (SGTU len idx)
(IsSliceInBounds idx len) -> (XORconst [1] (SGTU idx len))

// pseudo-ops
(GetClosurePtr) -> (LoweredGetClosurePtr)
(GetCallerSP) -> (LoweredGetCallerSP)
(GetCallerPC) -> (LoweredGetCallerPC)

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

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

(PanicBounds [kind] x y mem) && boundsABI(kind) == 0 -> (LoweredPanicBoundsA [kind] x y mem)
(PanicBounds [kind] x y mem) && boundsABI(kind) == 1 -> (LoweredPanicBoundsB [kind] x y mem)
(PanicBounds [kind] x y mem) && boundsABI(kind) == 2 -> (LoweredPanicBoundsC [kind] x y mem)

(PanicExtend [kind] hi lo y mem) && boundsABI(kind) == 0 -> (LoweredPanicExtendA [kind] hi lo y mem)
(PanicExtend [kind] hi lo y mem) && boundsABI(kind) == 1 -> (LoweredPanicExtendB [kind] hi lo y mem)
(PanicExtend [kind] hi lo y mem) && boundsABI(kind) == 2 -> (LoweredPanicExtendC [kind] hi lo y mem)

// Optimizations

// Absorb boolean tests into block
(NE (FPFlagTrue cmp) yes no) -> (FPT cmp yes no)
(NE (FPFlagFalse cmp) yes no) -> (FPF cmp yes no)
(EQ (FPFlagTrue cmp) yes no) -> (FPF cmp yes no)
(EQ (FPFlagFalse cmp) yes no) -> (FPT cmp yes no)
(NE (XORconst [1] cmp:(SGT _ _)) yes no) -> (EQ cmp yes no)
(NE (XORconst [1] cmp:(SGTU _ _)) yes no) -> (EQ cmp yes no)
(NE (XORconst [1] cmp:(SGTconst _)) yes no) -> (EQ cmp yes no)
(NE (XORconst [1] cmp:(SGTUconst _)) yes no) -> (EQ cmp yes no)
(NE (XORconst [1] cmp:(SGTzero _)) yes no) -> (EQ cmp yes no)
(NE (XORconst [1] cmp:(SGTUzero _)) yes no) -> (EQ cmp yes no)
(EQ (XORconst [1] cmp:(SGT _ _)) yes no) -> (NE cmp yes no)
(EQ (XORconst [1] cmp:(SGTU _ _)) yes no) -> (NE cmp yes no)
(EQ (XORconst [1] cmp:(SGTconst _)) yes no) -> (NE cmp yes no)
(EQ (XORconst [1] cmp:(SGTUconst _)) yes no) -> (NE cmp yes no)
(EQ (XORconst [1] cmp:(SGTzero _)) yes no) -> (NE cmp yes no)
(EQ (XORconst [1] cmp:(SGTUzero _)) yes no) -> (NE cmp yes no)
(NE (SGTUconst [1] x) yes no) -> (EQ x yes no)
(EQ (SGTUconst [1] x) yes no) -> (NE x yes no)
(NE (SGTUzero x) yes no) -> (NE x yes no)
(EQ (SGTUzero x) yes no) -> (EQ x yes no)
(NE (SGTconst [0] x) yes no) -> (LTZ x yes no)
(EQ (SGTconst [0] x) yes no) -> (GEZ x yes no)
(NE (SGTzero x) yes no) -> (GTZ x yes no)
(EQ (SGTzero x) yes no) -> (LEZ x yes no)

// fold offset into address
(ADDconst [off1] (MOVWaddr [off2] {sym} ptr)) -> (MOVWaddr [off1+off2] {sym} ptr)

// fold address into load/store
(MOVBload  [off1] {sym} x:(ADDconst [off2] ptr) mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVBload  [off1+off2] {sym} ptr mem)
(MOVBUload [off1] {sym} x:(ADDconst [off2] ptr) mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVBUload [off1+off2] {sym} ptr mem)
(MOVHload  [off1] {sym} x:(ADDconst [off2] ptr) mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVHload  [off1+off2] {sym} ptr mem)
(MOVHUload [off1] {sym} x:(ADDconst [off2] ptr) mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVHUload [off1+off2] {sym} ptr mem)
(MOVWload  [off1] {sym} x:(ADDconst [off2] ptr) mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVWload  [off1+off2] {sym} ptr mem)
(MOVFload  [off1] {sym} x:(ADDconst [off2] ptr) mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVFload  [off1+off2] {sym} ptr mem)
(MOVDload  [off1] {sym} x:(ADDconst [off2] ptr) mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVDload  [off1+off2] {sym} ptr mem)

(MOVBstore [off1] {sym} x:(ADDconst [off2] ptr) val mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVBstore [off1+off2] {sym} ptr val mem)
(MOVHstore [off1] {sym} x:(ADDconst [off2] ptr) val mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVHstore [off1+off2] {sym} ptr val mem)
(MOVWstore [off1] {sym} x:(ADDconst [off2] ptr) val mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVWstore [off1+off2] {sym} ptr val mem)
(MOVFstore [off1] {sym} x:(ADDconst [off2] ptr) val mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVFstore [off1+off2] {sym} ptr val mem)
(MOVDstore [off1] {sym} x:(ADDconst [off2] ptr) val mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVDstore [off1+off2] {sym} ptr val mem)

(MOVBstorezero [off1] {sym} x:(ADDconst [off2] ptr) mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVBstorezero [off1+off2] {sym} ptr mem)
(MOVHstorezero [off1] {sym} x:(ADDconst [off2] ptr) mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVHstorezero [off1+off2] {sym} ptr mem)
(MOVWstorezero [off1] {sym} x:(ADDconst [off2] ptr) mem) && (is16Bit(off1+off2) || x.Uses == 1) -> (MOVWstorezero [off1+off2] {sym} ptr mem)

(MOVBload [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) ->
	(MOVBload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
(MOVBUload [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) ->
	(MOVBUload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
(MOVHload [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) ->
	(MOVHload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
(MOVHUload [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) ->
	(MOVHUload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
(MOVWload [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) ->
	(MOVWload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
(MOVFload [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) ->
	(MOVFload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
(MOVDload [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) ->
	(MOVDload [off1+off2] {mergeSym(sym1,sym2)} ptr mem)

(MOVBstore [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) ->
	(MOVBstore [off1+off2] {mergeSym(sym1,sym2)} ptr val mem)
(MOVHstore [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) ->
	(MOVHstore [off1+off2] {mergeSym(sym1,sym2)} ptr val mem)
(MOVWstore [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) ->
	(MOVWstore [off1+off2] {mergeSym(sym1,sym2)} ptr val mem)
(MOVFstore [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) ->
	(MOVFstore [off1+off2] {mergeSym(sym1,sym2)} ptr val mem)
(MOVDstore [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) val mem) && canMergeSym(sym1,sym2) ->
	(MOVDstore [off1+off2] {mergeSym(sym1,sym2)} ptr val mem)
(MOVBstorezero [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) ->
	(MOVBstorezero [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
(MOVHstorezero [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) ->
	(MOVHstorezero [off1+off2] {mergeSym(sym1,sym2)} ptr mem)
(MOVWstorezero [off1] {sym1} (MOVWaddr [off2] {sym2} ptr) mem) && canMergeSym(sym1,sym2) ->
	(MOVWstorezero [off1+off2] {mergeSym(sym1,sym2)} ptr 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) -> (MOVBreg x)
(MOVBUload [off] {sym} ptr (MOVBstore [off2] {sym2} ptr2 x _)) && sym == sym2 && off == off2 && isSamePtr(ptr, ptr2) -> (MOVBUreg x)
(MOVHload [off] {sym} ptr (MOVHstore [off2] {sym2} ptr2 x _)) && sym == sym2 && off == off2 && isSamePtr(ptr, ptr2) -> (MOVHreg x)
(MOVHUload [off] {sym} ptr (MOVHstore [off2] {sym2} ptr2 x _)) && sym == sym2 && off == off2 && isSamePtr(ptr, ptr2) -> (MOVHUreg x)
(MOVWload [off] {sym} ptr (MOVWstore [off2] {sym2} ptr2 x _)) && sym == sym2 && off == off2 && isSamePtr(ptr, ptr2) -> x
(MOVFload [off] {sym} ptr (MOVFstore [off2] {sym2} ptr2 x _)) && sym == sym2 && off == off2 && isSamePtr(ptr, ptr2) -> x
(MOVDload [off] {sym} ptr (MOVDstore [off2] {sym2} ptr2 x _)) && sym == sym2 && off == off2 && isSamePtr(ptr, ptr2) -> x

// store zero
(MOVBstore [off] {sym} ptr (MOVWconst [0]) mem) -> (MOVBstorezero [off] {sym} ptr mem)
(MOVHstore [off] {sym} ptr (MOVWconst [0]) mem) -> (MOVHstorezero [off] {sym} ptr mem)
(MOVWstore [off] {sym} ptr (MOVWconst [0]) mem) -> (MOVWstorezero [off] {sym} ptr mem)

// don't extend after proper load
(MOVBreg x:(MOVBload _ _)) -> (MOVWreg x)
(MOVBUreg x:(MOVBUload _ _)) -> (MOVWreg x)
(MOVHreg x:(MOVBload _ _)) -> (MOVWreg x)
(MOVHreg x:(MOVBUload _ _)) -> (MOVWreg x)
(MOVHreg x:(MOVHload _ _)) -> (MOVWreg x)
(MOVHUreg x:(MOVBUload _ _)) -> (MOVWreg x)
(MOVHUreg x:(MOVHUload _ _)) -> (MOVWreg x)

// fold double extensions
(MOVBreg x:(MOVBreg _)) -> (MOVWreg x)
(MOVBUreg x:(MOVBUreg _)) -> (MOVWreg x)
(MOVHreg x:(MOVBreg _)) -> (MOVWreg x)
(MOVHreg x:(MOVBUreg _)) -> (MOVWreg x)
(MOVHreg x:(MOVHreg _)) -> (MOVWreg x)
(MOVHUreg x:(MOVBUreg _)) -> (MOVWreg x)
(MOVHUreg x:(MOVHUreg _)) -> (MOVWreg 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.
(MOVBreg <t> x:(MOVBUload [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) -> @x.Block (MOVBload <t> [off] {sym} ptr mem)
(MOVBUreg <t> x:(MOVBload [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) -> @x.Block (MOVBUload <t> [off] {sym} ptr mem)
(MOVHreg <t> x:(MOVHUload [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) -> @x.Block (MOVHload <t> [off] {sym} ptr mem)
(MOVHUreg <t> x:(MOVHload [off] {sym} ptr mem)) && x.Uses == 1 && clobber(x) -> @x.Block (MOVHUload <t> [off] {sym} ptr mem)

// fold extensions and ANDs together
(MOVBUreg (ANDconst [c] x)) -> (ANDconst [c&0xff] x)
(MOVHUreg (ANDconst [c] x)) -> (ANDconst [c&0xffff] x)
(MOVBreg (ANDconst [c] x)) && c & 0x80 == 0 -> (ANDconst [c&0x7f] x)
(MOVHreg (ANDconst [c] x)) && c & 0x8000 == 0 -> (ANDconst [c&0x7fff] x)

// don't extend before store
(MOVBstore [off] {sym} ptr (MOVBreg x) mem) -> (MOVBstore [off] {sym} ptr x mem)
(MOVBstore [off] {sym} ptr (MOVBUreg x) mem) -> (MOVBstore [off] {sym} ptr x mem)
(MOVBstore [off] {sym} ptr (MOVHreg x) mem) -> (MOVBstore [off] {sym} ptr x mem)
(MOVBstore [off] {sym} ptr (MOVHUreg x) mem) -> (MOVBstore [off] {sym} ptr x mem)
(MOVBstore [off] {sym} ptr (MOVWreg x) mem) -> (MOVBstore [off] {sym} ptr x mem)
(MOVHstore [off] {sym} ptr (MOVHreg x) mem) -> (MOVHstore [off] {sym} ptr x mem)
(MOVHstore [off] {sym} ptr (MOVHUreg x) mem) -> (MOVHstore [off] {sym} ptr x mem)
(MOVHstore [off] {sym} ptr (MOVWreg x) mem) -> (MOVHstore [off] {sym} ptr x mem)
(MOVWstore [off] {sym} ptr (MOVWreg x) mem) -> (MOVWstore [off] {sym} ptr x mem)

// if a register move has only 1 use, just use the same register without emitting instruction
// MOVWnop doesn't emit instruction, only for ensuring the type.
(MOVWreg x) && x.Uses == 1 -> (MOVWnop x)

// fold constant into arithmatic ops
(ADD x (MOVWconst [c])) -> (ADDconst [c] x)
(SUB x (MOVWconst [c])) -> (SUBconst [c] x)
(AND x (MOVWconst [c])) -> (ANDconst [c] x)
(OR  x (MOVWconst [c])) -> (ORconst  [c] x)
(XOR x (MOVWconst [c])) -> (XORconst [c] x)
(NOR x (MOVWconst [c])) -> (NORconst [c] x)

(SLL _ (MOVWconst [c])) && uint32(c)>=32 -> (MOVWconst [0])
(SRL _ (MOVWconst [c])) && uint32(c)>=32 -> (MOVWconst [0])
(SRA x (MOVWconst [c])) && uint32(c)>=32 -> (SRAconst x [31])
(SLL x (MOVWconst [c])) -> (SLLconst x [c])
(SRL x (MOVWconst [c])) -> (SRLconst x [c])
(SRA x (MOVWconst [c])) -> (SRAconst x [c])

(SGT  (MOVWconst [c]) x) -> (SGTconst  [c] x)
(SGTU (MOVWconst [c]) x) -> (SGTUconst [c] x)
(SGT x (MOVWconst [0])) -> (SGTzero x)
(SGTU x (MOVWconst [0])) -> (SGTUzero x)

// mul with constant
(Select1 (MULTU (MOVWconst [0]) _ )) -> (MOVWconst [0])
(Select0 (MULTU (MOVWconst [0]) _ )) -> (MOVWconst [0])
(Select1 (MULTU (MOVWconst [1]) x )) -> x
(Select0 (MULTU (MOVWconst [1]) _ )) -> (MOVWconst [0])
(Select1 (MULTU (MOVWconst [-1]) x )) -> (NEG <x.Type> x)
(Select0 (MULTU (MOVWconst [-1]) x )) -> (CMOVZ (ADDconst <x.Type> [-1] x) (MOVWconst [0]) x)
(Select1 (MULTU (MOVWconst [c]) x )) && isPowerOfTwo(int64(uint32(c))) -> (SLLconst [log2(int64(uint32(c)))] x)
(Select0 (MULTU (MOVWconst [c]) x )) && isPowerOfTwo(int64(uint32(c))) -> (SRLconst [32-log2(int64(uint32(c)))] x)

(MUL (MOVWconst [0]) _ ) -> (MOVWconst [0])
(MUL (MOVWconst [1]) x ) -> x
(MUL (MOVWconst [-1]) x ) -> (NEG x)
(MUL (MOVWconst [c]) x ) && isPowerOfTwo(int64(uint32(c))) -> (SLLconst [log2(int64(uint32(c)))] x)

// generic simplifications
(ADD x (NEG y)) -> (SUB x y)
(SUB x x) -> (MOVWconst [0])
(SUB (MOVWconst [0]) x) -> (NEG x)
(AND x x) -> x
(OR  x x) -> x
(XOR x x) -> (MOVWconst [0])

// miscellaneous patterns generated by dec64
(AND (SGTUconst [1] x) (SGTUconst [1] y)) ->  (SGTUconst [1] (OR <x.Type> x y))
(OR (SGTUzero x) (SGTUzero y)) ->  (SGTUzero (OR <x.Type> x y))

// remove redundant *const ops
(ADDconst [0]  x) -> x
(SUBconst [0]  x) -> x
(ANDconst [0]  _) -> (MOVWconst [0])
(ANDconst [-1] x) -> x
(ORconst  [0]  x) -> x
(ORconst  [-1] _) -> (MOVWconst [-1])
(XORconst [0]  x) -> x
(XORconst [-1] x) -> (NORconst [0] x)

// generic constant folding
(ADDconst [c] (MOVWconst [d]))  -> (MOVWconst [int64(int32(c+d))])
(ADDconst [c] (ADDconst [d] x)) -> (ADDconst [int64(int32(c+d))] x)
(ADDconst [c] (SUBconst [d] x)) -> (ADDconst [int64(int32(c-d))] x)
(SUBconst [c] (MOVWconst [d]))  -> (MOVWconst [int64(int32(d-c))])
(SUBconst [c] (SUBconst [d] x)) -> (ADDconst [int64(int32(-c-d))] x)
(SUBconst [c] (ADDconst [d] x)) -> (ADDconst [int64(int32(-c+d))] x)
(SLLconst [c] (MOVWconst [d]))  -> (MOVWconst [int64(int32(uint32(d)<<uint32(c)))])
(SRLconst [c] (MOVWconst [d]))  -> (MOVWconst [int64(uint32(d)>>uint32(c))])
(SRAconst [c] (MOVWconst [d]))  -> (MOVWconst [int64(int32(d)>>uint32(c))])
(MUL (MOVWconst [c]) (MOVWconst [d])) -> (MOVWconst [int64(int32(c)*int32(d))])
(Select1 (MULTU  (MOVWconst [c]) (MOVWconst [d]))) -> (MOVWconst [int64(int32(uint32(c)*uint32(d)))])
(Select0 (MULTU  (MOVWconst [c]) (MOVWconst [d]))) -> (MOVWconst [(c*d)>>32])
(Select1 (DIV  (MOVWconst [c]) (MOVWconst [d]))) -> (MOVWconst [int64(int32(c)/int32(d))])
(Select1 (DIVU (MOVWconst [c]) (MOVWconst [d]))) -> (MOVWconst [int64(int32(uint32(c)/uint32(d)))])
(Select0 (DIV  (MOVWconst [c]) (MOVWconst [d]))) -> (MOVWconst [int64(int32(c)%int32(d))])
(Select0 (DIVU (MOVWconst [c]) (MOVWconst [d]))) -> (MOVWconst [int64(int32(uint32(c)%uint32(d)))])
(ANDconst [c] (MOVWconst [d])) -> (MOVWconst [c&d])
(ANDconst [c] (ANDconst [d] x)) -> (ANDconst [c&d] x)
(ORconst [c] (MOVWconst [d])) -> (MOVWconst [c|d])
(ORconst [c] (ORconst [d] x)) -> (ORconst [c|d] x)
(XORconst [c] (MOVWconst [d])) -> (MOVWconst [c^d])
(XORconst [c] (XORconst [d] x)) -> (XORconst [c^d] x)
(NORconst [c] (MOVWconst [d])) -> (MOVWconst [^(c|d)])
(NEG (MOVWconst [c])) -> (MOVWconst [int64(int32(-c))])
(MOVBreg  (MOVWconst [c])) -> (MOVWconst [int64(int8(c))])
(MOVBUreg (MOVWconst [c])) -> (MOVWconst [int64(uint8(c))])
(MOVHreg  (MOVWconst [c])) -> (MOVWconst [int64(int16(c))])
(MOVHUreg (MOVWconst [c])) -> (MOVWconst [int64(uint16(c))])
(MOVWreg  (MOVWconst [c])) -> (MOVWconst [c])

// constant comparisons
(SGTconst [c] (MOVWconst [d])) && int32(c) > int32(d) -> (MOVWconst [1])
(SGTconst [c] (MOVWconst [d])) && int32(c) <= int32(d) -> (MOVWconst [0])
(SGTUconst [c] (MOVWconst [d])) && uint32(c)>uint32(d) -> (MOVWconst [1])
(SGTUconst [c] (MOVWconst [d])) && uint32(c)<=uint32(d) -> (MOVWconst [0])
(SGTzero (MOVWconst [d])) && int32(d) > 0 -> (MOVWconst [1])
(SGTzero (MOVWconst [d])) && int32(d) <= 0 -> (MOVWconst [0])
(SGTUzero (MOVWconst [d])) && uint32(d) != 0 -> (MOVWconst [1])
(SGTUzero (MOVWconst [d])) && uint32(d) == 0 -> (MOVWconst [0])

// other known comparisons
(SGTconst [c] (MOVBreg _)) && 0x7f < int32(c) -> (MOVWconst [1])
(SGTconst [c] (MOVBreg _)) && int32(c) <= -0x80 -> (MOVWconst [0])
(SGTconst [c] (MOVBUreg _)) && 0xff < int32(c) -> (MOVWconst [1])
(SGTconst [c] (MOVBUreg _)) && int32(c) < 0 -> (MOVWconst [0])
(SGTUconst [c] (MOVBUreg _)) && 0xff < uint32(c) -> (MOVWconst [1])
(SGTconst [c] (MOVHreg _)) && 0x7fff < int32(c) -> (MOVWconst [1])
(SGTconst [c] (MOVHreg _)) && int32(c) <= -0x8000 -> (MOVWconst [0])
(SGTconst [c] (MOVHUreg _)) && 0xffff < int32(c) -> (MOVWconst [1])
(SGTconst [c] (MOVHUreg _)) && int32(c) < 0 -> (MOVWconst [0])
(SGTUconst [c] (MOVHUreg _)) && 0xffff < uint32(c) -> (MOVWconst [1])
(SGTconst [c] (ANDconst [m] _)) && 0 <= int32(m) && int32(m) < int32(c) -> (MOVWconst [1])
(SGTUconst [c] (ANDconst [m] _)) && uint32(m) < uint32(c) -> (MOVWconst [1])
(SGTconst [c] (SRLconst _ [d])) && 0 <= int32(c) && uint32(d) <= 31 && 0xffffffff>>uint32(d) < uint32(c) -> (MOVWconst [1])
(SGTUconst [c] (SRLconst _ [d])) && uint32(d) <= 31 && 0xffffffff>>uint32(d) < uint32(c) -> (MOVWconst [1])

// absorb constants into branches
(EQ  (MOVWconst [0]) yes no) -> (First yes no)
(EQ  (MOVWconst [c]) yes no) && c != 0 -> (First no yes)
(NE  (MOVWconst [0]) yes no) -> (First no yes)
(NE  (MOVWconst [c]) yes no) && c != 0 -> (First yes no)
(LTZ (MOVWconst [c]) yes no) && int32(c) <  0 -> (First yes no)
(LTZ (MOVWconst [c]) yes no) && int32(c) >= 0 -> (First no yes)
(LEZ (MOVWconst [c]) yes no) && int32(c) <= 0 -> (First yes no)
(LEZ (MOVWconst [c]) yes no) && int32(c) >  0 -> (First no yes)
(GTZ (MOVWconst [c]) yes no) && int32(c) >  0 -> (First yes no)
(GTZ (MOVWconst [c]) yes no) && int32(c) <= 0 -> (First no yes)
(GEZ (MOVWconst [c]) yes no) && int32(c) >= 0 -> (First yes no)
(GEZ (MOVWconst [c]) yes no) && int32(c) <  0 -> (First no yes)

// conditional move
(CMOVZ _ f (MOVWconst [0])) -> f
(CMOVZ a _ (MOVWconst [c])) && c!=0 -> a
(CMOVZzero _ (MOVWconst [0])) -> (MOVWconst [0])
(CMOVZzero a (MOVWconst [c])) && c!=0 -> a
(CMOVZ a (MOVWconst [0]) c) -> (CMOVZzero a c)

// atomic
(LoweredAtomicStore32 ptr (MOVWconst [0]) mem) -> (LoweredAtomicStorezero ptr mem)
(LoweredAtomicAdd ptr (MOVWconst [c]) mem) && is16Bit(c) -> (LoweredAtomicAddconst [c] ptr mem)