cmd/compile: optimize store combination on 386/amd64

This CL add 3 rules to combine byte-store to word-store on386 and
amd64.

Change-Id: Iffd9cda42f1961680c81def4edc773ad58f211b3
Reviewed-on: https://go-review.googlesource.com/c/143057
Run-TryBot: Ben Shi <powerman1st@163.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

src/cmd/compile/internal/ssa/gen/386.rules

@@ -1127,11 +1127,21 @@
   && 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)
+(MOVBstoreconst [a] {s} p x:(MOVBstoreconst [c] {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)
+(MOVWstoreconst [a] {s} p x:(MOVWstoreconst [c] {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

src/cmd/compile/internal/ssa/gen/AMD64.rules

@@ -2125,16 +2125,31 @@
   && 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)
+(MOVBstoreconst [a] {s} p x:(MOVBstoreconst [c] {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)
+(MOVWstoreconst [a] {s} p x:(MOVWstoreconst [c] {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)
 (MOVLstoreconst [c] {s} p x:(MOVLstoreconst [a] {s} p mem))
   && x.Uses == 1
   && ValAndOff(a).Off() + 4 == ValAndOff(c).Off()
   && clobber(x)
   -> (MOVQstore [ValAndOff(a).Off()] {s} p (MOVQconst [ValAndOff(a).Val()&0xffffffff | ValAndOff(c).Val()<<32]) mem)
+(MOVLstoreconst [a] {s} p x:(MOVLstoreconst [c] {s} p mem))
+  && x.Uses == 1
+  && ValAndOff(a).Off() + 4 == ValAndOff(c).Off()
+  && clobber(x)
+  -> (MOVQstore [ValAndOff(a).Off()] {s} p (MOVQconst [ValAndOff(a).Val()&0xffffffff | ValAndOff(c).Val()<<32]) mem)
 (MOVQstoreconst [c] {s} p x:(MOVQstoreconst [c2] {s} p mem))
   && config.useSSE
   && x.Uses == 1
@@ -2176,6 +2191,10 @@
   && x.Uses == 1
   && clobber(x)
   -> (MOVWstore [i-1] {s} p w mem)
+(MOVBstore [i] {s} p w x:(MOVBstore [i+1] {s} p (SHR(W|L|Q)const [8] w) mem))
+  && x.Uses == 1
+  && clobber(x)
+  -> (MOVWstore [i] {s} p w mem)
 (MOVBstore [i] {s} p (SHR(L|Q)const [j] w) x:(MOVBstore [i-1] {s} p w0:(SHR(L|Q)const [j-8] w) mem))
   && x.Uses == 1
   && clobber(x)

src/cmd/compile/internal/ssa/rewrite386.go

@@ -5916,6 +5916,37 @@ func rewriteValue386_Op386MOVBstoreconst_0(v *Value) bool {
 		v.AddArg(mem)
 		return true
 	}
+	// match: (MOVBstoreconst [a] {s} p x:(MOVBstoreconst [c] {s} p mem))
+	// cond: x.Uses == 1 && ValAndOff(a).Off() + 1 == ValAndOff(c).Off() && clobber(x)
+	// result: (MOVWstoreconst [makeValAndOff(ValAndOff(a).Val()&0xff | ValAndOff(c).Val()<<8, ValAndOff(a).Off())] {s} p mem)
+	for {
+		a := v.AuxInt
+		s := v.Aux
+		_ = v.Args[1]
+		p := v.Args[0]
+		x := v.Args[1]
+		if x.Op != Op386MOVBstoreconst {
+			break
+		}
+		c := x.AuxInt
+		if x.Aux != s {
+			break
+		}
+		_ = x.Args[1]
+		if p != x.Args[0] {
+			break
+		}
+		mem := x.Args[1]
+		if !(x.Uses == 1 && ValAndOff(a).Off()+1 == ValAndOff(c).Off() && clobber(x)) {
+			break
+		}
+		v.reset(Op386MOVWstoreconst)
+		v.AuxInt = makeValAndOff(ValAndOff(a).Val()&0xff|ValAndOff(c).Val()<<8, ValAndOff(a).Off())
+		v.Aux = s
+		v.AddArg(p)
+		v.AddArg(mem)
+		return true
+	}
 	return false
 }
 func rewriteValue386_Op386MOVBstoreconstidx1_0(v *Value) bool {
@@ -11729,6 +11760,37 @@ func rewriteValue386_Op386MOVWstoreconst_0(v *Value) bool {
 		v.AddArg(mem)
 		return true
 	}
+	// match: (MOVWstoreconst [a] {s} p x:(MOVWstoreconst [c] {s} p mem))
+	// cond: x.Uses == 1 && ValAndOff(a).Off() + 2 == ValAndOff(c).Off() && clobber(x)
+	// result: (MOVLstoreconst [makeValAndOff(ValAndOff(a).Val()&0xffff | ValAndOff(c).Val()<<16, ValAndOff(a).Off())] {s} p mem)
+	for {
+		a := v.AuxInt
+		s := v.Aux
+		_ = v.Args[1]
+		p := v.Args[0]
+		x := v.Args[1]
+		if x.Op != Op386MOVWstoreconst {
+			break
+		}
+		c := x.AuxInt
+		if x.Aux != s {
+			break
+		}
+		_ = x.Args[1]
+		if p != x.Args[0] {
+			break
+		}
+		mem := x.Args[1]
+		if !(x.Uses == 1 && ValAndOff(a).Off()+2 == ValAndOff(c).Off() && clobber(x)) {
+			break
+		}
+		v.reset(Op386MOVLstoreconst)
+		v.AuxInt = makeValAndOff(ValAndOff(a).Val()&0xffff|ValAndOff(c).Val()<<16, ValAndOff(a).Off())
+		v.Aux = s
+		v.AddArg(p)
+		v.AddArg(mem)
+		return true
+	}
 	return false
 }
 func rewriteValue386_Op386MOVWstoreconstidx1_0(v *Value) bool {

src/cmd/compile/internal/ssa/rewriteAMD64.go

@@ -248,7 +248,7 @@ func rewriteValueAMD64(v *Value) bool {
 	case OpAMD64MOVBloadidx1:
 		return rewriteValueAMD64_OpAMD64MOVBloadidx1_0(v)
 	case OpAMD64MOVBstore:
-		return rewriteValueAMD64_OpAMD64MOVBstore_0(v) || rewriteValueAMD64_OpAMD64MOVBstore_10(v) || rewriteValueAMD64_OpAMD64MOVBstore_20(v)
+		return rewriteValueAMD64_OpAMD64MOVBstore_0(v) || rewriteValueAMD64_OpAMD64MOVBstore_10(v) || rewriteValueAMD64_OpAMD64MOVBstore_20(v) || rewriteValueAMD64_OpAMD64MOVBstore_30(v)
 	case OpAMD64MOVBstoreconst:
 		return rewriteValueAMD64_OpAMD64MOVBstoreconst_0(v)
 	case OpAMD64MOVBstoreconstidx1:
@@ -13556,6 +13556,141 @@ func rewriteValueAMD64_OpAMD64MOVBstore_20(v *Value) bool {
 		v.AddArg(mem)
 		return true
 	}
+	// match: (MOVBstore [i] {s} p w x:(MOVBstore [i+1] {s} p (SHRWconst [8] w) mem))
+	// cond: x.Uses == 1 && clobber(x)
+	// result: (MOVWstore [i] {s} p w mem)
+	for {
+		i := v.AuxInt
+		s := v.Aux
+		_ = v.Args[2]
+		p := v.Args[0]
+		w := v.Args[1]
+		x := v.Args[2]
+		if x.Op != OpAMD64MOVBstore {
+			break
+		}
+		if x.AuxInt != i+1 {
+			break
+		}
+		if x.Aux != s {
+			break
+		}
+		_ = x.Args[2]
+		if p != x.Args[0] {
+			break
+		}
+		x_1 := x.Args[1]
+		if x_1.Op != OpAMD64SHRWconst {
+			break
+		}
+		if x_1.AuxInt != 8 {
+			break
+		}
+		if w != x_1.Args[0] {
+			break
+		}
+		mem := x.Args[2]
+		if !(x.Uses == 1 && clobber(x)) {
+			break
+		}
+		v.reset(OpAMD64MOVWstore)
+		v.AuxInt = i
+		v.Aux = s
+		v.AddArg(p)
+		v.AddArg(w)
+		v.AddArg(mem)
+		return true
+	}
+	// match: (MOVBstore [i] {s} p w x:(MOVBstore [i+1] {s} p (SHRLconst [8] w) mem))
+	// cond: x.Uses == 1 && clobber(x)
+	// result: (MOVWstore [i] {s} p w mem)
+	for {
+		i := v.AuxInt
+		s := v.Aux
+		_ = v.Args[2]
+		p := v.Args[0]
+		w := v.Args[1]
+		x := v.Args[2]
+		if x.Op != OpAMD64MOVBstore {
+			break
+		}
+		if x.AuxInt != i+1 {
+			break
+		}
+		if x.Aux != s {
+			break
+		}
+		_ = x.Args[2]
+		if p != x.Args[0] {
+			break
+		}
+		x_1 := x.Args[1]
+		if x_1.Op != OpAMD64SHRLconst {
+			break
+		}
+		if x_1.AuxInt != 8 {
+			break
+		}
+		if w != x_1.Args[0] {
+			break
+		}
+		mem := x.Args[2]
+		if !(x.Uses == 1 && clobber(x)) {
+			break
+		}
+		v.reset(OpAMD64MOVWstore)
+		v.AuxInt = i
+		v.Aux = s
+		v.AddArg(p)
+		v.AddArg(w)
+		v.AddArg(mem)
+		return true
+	}
+	// match: (MOVBstore [i] {s} p w x:(MOVBstore [i+1] {s} p (SHRQconst [8] w) mem))
+	// cond: x.Uses == 1 && clobber(x)
+	// result: (MOVWstore [i] {s} p w mem)
+	for {
+		i := v.AuxInt
+		s := v.Aux
+		_ = v.Args[2]
+		p := v.Args[0]
+		w := v.Args[1]
+		x := v.Args[2]
+		if x.Op != OpAMD64MOVBstore {
+			break
+		}
+		if x.AuxInt != i+1 {
+			break
+		}
+		if x.Aux != s {
+			break
+		}
+		_ = x.Args[2]
+		if p != x.Args[0] {
+			break
+		}
+		x_1 := x.Args[1]
+		if x_1.Op != OpAMD64SHRQconst {
+			break
+		}
+		if x_1.AuxInt != 8 {
+			break
+		}
+		if w != x_1.Args[0] {
+			break
+		}
+		mem := x.Args[2]
+		if !(x.Uses == 1 && clobber(x)) {
+			break
+		}
+		v.reset(OpAMD64MOVWstore)
+		v.AuxInt = i
+		v.Aux = s
+		v.AddArg(p)
+		v.AddArg(w)
+		v.AddArg(mem)
+		return true
+	}
 	// match: (MOVBstore [i] {s} p (SHRLconst [j] w) x:(MOVBstore [i-1] {s} p w0:(SHRLconst [j-8] w) mem))
 	// cond: x.Uses == 1 && clobber(x)
 	// result: (MOVWstore [i-1] {s} p w0 mem)
@@ -13723,6 +13858,9 @@ func rewriteValueAMD64_OpAMD64MOVBstore_20(v *Value) bool {
 		v.AddArg(mem)
 		return true
 	}
+	return false
+}
+func rewriteValueAMD64_OpAMD64MOVBstore_30(v *Value) bool {
 	// match: (MOVBstore [off1] {sym1} (LEAL [off2] {sym2} base) val mem)
 	// cond: canMergeSym(sym1, sym2) && is32Bit(off1+off2)
 	// result: (MOVBstore [off1+off2] {mergeSym(sym1,sym2)} base val mem)
@@ -13910,6 +14048,37 @@ func rewriteValueAMD64_OpAMD64MOVBstoreconst_0(v *Value) bool {
 		v.AddArg(mem)
 		return true
 	}
+	// match: (MOVBstoreconst [a] {s} p x:(MOVBstoreconst [c] {s} p mem))
+	// cond: x.Uses == 1 && ValAndOff(a).Off() + 1 == ValAndOff(c).Off() && clobber(x)
+	// result: (MOVWstoreconst [makeValAndOff(ValAndOff(a).Val()&0xff | ValAndOff(c).Val()<<8, ValAndOff(a).Off())] {s} p mem)
+	for {
+		a := v.AuxInt
+		s := v.Aux
+		_ = v.Args[1]
+		p := v.Args[0]
+		x := v.Args[1]
+		if x.Op != OpAMD64MOVBstoreconst {
+			break
+		}
+		c := x.AuxInt
+		if x.Aux != s {
+			break
+		}
+		_ = x.Args[1]
+		if p != x.Args[0] {
+			break
+		}
+		mem := x.Args[1]
+		if !(x.Uses == 1 && ValAndOff(a).Off()+1 == ValAndOff(c).Off() && clobber(x)) {
+			break
+		}
+		v.reset(OpAMD64MOVWstoreconst)
+		v.AuxInt = makeValAndOff(ValAndOff(a).Val()&0xff|ValAndOff(c).Val()<<8, ValAndOff(a).Off())
+		v.Aux = s
+		v.AddArg(p)
+		v.AddArg(mem)
+		return true
+	}
 	// match: (MOVBstoreconst [sc] {sym1} (LEAL [off] {sym2} ptr) mem)
 	// cond: canMergeSym(sym1, sym2) && ValAndOff(sc).canAdd(off)
 	// result: (MOVBstoreconst [ValAndOff(sc).add(off)] {mergeSym(sym1, sym2)} ptr mem)
@@ -17553,6 +17722,40 @@ func rewriteValueAMD64_OpAMD64MOVLstoreconst_0(v *Value) bool {
 		v.AddArg(mem)
 		return true
 	}
+	// match: (MOVLstoreconst [a] {s} p x:(MOVLstoreconst [c] {s} p mem))
+	// cond: x.Uses == 1 && ValAndOff(a).Off() + 4 == ValAndOff(c).Off() && clobber(x)
+	// result: (MOVQstore [ValAndOff(a).Off()] {s} p (MOVQconst [ValAndOff(a).Val()&0xffffffff | ValAndOff(c).Val()<<32]) mem)
+	for {
+		a := v.AuxInt
+		s := v.Aux
+		_ = v.Args[1]
+		p := v.Args[0]
+		x := v.Args[1]
+		if x.Op != OpAMD64MOVLstoreconst {
+			break
+		}
+		c := x.AuxInt
+		if x.Aux != s {
+			break
+		}
+		_ = x.Args[1]
+		if p != x.Args[0] {
+			break
+		}
+		mem := x.Args[1]
+		if !(x.Uses == 1 && ValAndOff(a).Off()+4 == ValAndOff(c).Off() && clobber(x)) {
+			break
+		}
+		v.reset(OpAMD64MOVQstore)
+		v.AuxInt = ValAndOff(a).Off()
+		v.Aux = s
+		v.AddArg(p)
+		v0 := b.NewValue0(v.Pos, OpAMD64MOVQconst, typ.UInt64)
+		v0.AuxInt = ValAndOff(a).Val()&0xffffffff | ValAndOff(c).Val()<<32
+		v.AddArg(v0)
+		v.AddArg(mem)
+		return true
+	}
 	// match: (MOVLstoreconst [sc] {sym1} (LEAL [off] {sym2} ptr) mem)
 	// cond: canMergeSym(sym1, sym2) && ValAndOff(sc).canAdd(off)
 	// result: (MOVLstoreconst [ValAndOff(sc).add(off)] {mergeSym(sym1, sym2)} ptr mem)
@@ -23867,6 +24070,37 @@ func rewriteValueAMD64_OpAMD64MOVWstoreconst_0(v *Value) bool {
 		v.AddArg(mem)
 		return true
 	}
+	// match: (MOVWstoreconst [a] {s} p x:(MOVWstoreconst [c] {s} p mem))
+	// cond: x.Uses == 1 && ValAndOff(a).Off() + 2 == ValAndOff(c).Off() && clobber(x)
+	// result: (MOVLstoreconst [makeValAndOff(ValAndOff(a).Val()&0xffff | ValAndOff(c).Val()<<16, ValAndOff(a).Off())] {s} p mem)
+	for {
+		a := v.AuxInt
+		s := v.Aux
+		_ = v.Args[1]
+		p := v.Args[0]
+		x := v.Args[1]
+		if x.Op != OpAMD64MOVWstoreconst {
+			break
+		}
+		c := x.AuxInt
+		if x.Aux != s {
+			break
+		}
+		_ = x.Args[1]
+		if p != x.Args[0] {
+			break
+		}
+		mem := x.Args[1]
+		if !(x.Uses == 1 && ValAndOff(a).Off()+2 == ValAndOff(c).Off() && clobber(x)) {
+			break
+		}
+		v.reset(OpAMD64MOVLstoreconst)
+		v.AuxInt = makeValAndOff(ValAndOff(a).Val()&0xffff|ValAndOff(c).Val()<<16, ValAndOff(a).Off())
+		v.Aux = s
+		v.AddArg(p)
+		v.AddArg(mem)
+		return true
+	}
 	// match: (MOVWstoreconst [sc] {sym1} (LEAL [off] {sym2} ptr) mem)
 	// cond: canMergeSym(sym1, sym2) && ValAndOff(sc).canAdd(off)
 	// result: (MOVWstoreconst [ValAndOff(sc).add(off)] {mergeSym(sym1, sym2)} ptr mem)

test/codegen/memcombine.go

@@ -434,6 +434,7 @@ func store_le_byte_2(b []byte, val uint16) {
 func store_le_byte_2_inv(b []byte, val uint16) {
 	_ = b[2]
 	// 386:`MOVW\s[A-Z]+,\s1\([A-Z]+\)`,-`MOVB`
+	// amd64:`MOVW\s[A-Z]+,\s1\([A-Z]+\)`,-`MOVB`
 	b[2], b[1] = byte(val>>8), byte(val)
 }
 
@@ -542,6 +543,8 @@ func zero_byte_2(b1, b2 []byte) {
 	// 386:`MOVW\s[$]0,\s\([A-Z]+\)`
 	b1[0], b1[1] = 0, 0
 	// arm64:"MOVH\tZR",-"MOVB"
+	// 386:`MOVW\s[$]0,\s\([A-Z]+\)`
+	// amd64:`MOVW\s[$]0,\s\([A-Z]+\)`
 	b2[1], b2[0] = 0, 0
 }
 
@@ -596,6 +599,8 @@ func zero_uint16_2(h1, h2 []uint16) {
 	// 386:`MOVL\s[$]0,\s\([A-Z]+\)`
 	h1[0], h1[1] = 0, 0
 	// arm64:"MOVW\tZR",-"MOVB",-"MOVH"
+	// amd64:`MOVL\s[$]0,\s\([A-Z]+\)`
+	// 386:`MOVL\s[$]0,\s\([A-Z]+\)`
 	h2[1], h2[0] = 0, 0
 }
 
@@ -620,6 +625,7 @@ func zero_uint32_2(w1, w2 []uint32) {
 	// amd64:`MOVQ\s[$]0,\s\([A-Z]+\)`
 	w1[0], w1[1] = 0, 0
 	// arm64:"MOVD\tZR",-"MOVB",-"MOVH",-"MOVW"
+	// amd64:`MOVQ\s[$]0,\s\([A-Z]+\)`
 	w2[1], w2[0] = 0, 0
 }