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cmd/compile: memcombine if values being stored are from consecutive loads

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If we load 2 values and then store those 2 loaded values, we can likely
perform that operation with a single wider load and store.

Fixes #60709

Change-Id: Ifc5f92c2f1b174c6ed82a69070f16cec6853c770
Reviewed-on: https://go-review.googlesource.com/c/go/+/502295
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
This commit is contained in:
Keith Randall 2023-06-10 08:26:34 -07:00 committed by David Chase
parent ffd9bd7e60
commit e713d6f939
4 changed files with 92 additions and 159 deletions
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30
src/cmd/compile/internal/ssa/_gen/AMD64.rules
View File

@ -1487,36 +1487,6 @@
&& clobber(x)
=> (MOVOstoreconst [makeValAndOff(0,a.Off())] {s} p0 mem)
(MOVBstore [i] {s} p
x1:(MOVBload [j] {s2} p2 mem)
mem2:(MOVBstore [i-1] {s} p
x2:(MOVBload [j-1] {s2} p2 mem) mem))
&& x1.Uses == 1
&& x2.Uses == 1
&& mem2.Uses == 1
&& clobber(x1, x2, mem2)
=> (MOVWstore [i-1] {s} p (MOVWload [j-1] {s2} p2 mem) mem)
(MOVWstore [i] {s} p
x1:(MOVWload [j] {s2} p2 mem)
mem2:(MOVWstore [i-2] {s} p
x2:(MOVWload [j-2] {s2} p2 mem) mem))
&& x1.Uses == 1
&& x2.Uses == 1
&& mem2.Uses == 1
&& clobber(x1, x2, mem2)
=> (MOVLstore [i-2] {s} p (MOVLload [j-2] {s2} p2 mem) mem)
(MOVLstore [i] {s} p
x1:(MOVLload [j] {s2} p2 mem)
mem2:(MOVLstore [i-4] {s} p
x2:(MOVLload [j-4] {s2} p2 mem) mem))
&& x1.Uses == 1
&& x2.Uses == 1
&& mem2.Uses == 1
&& clobber(x1, x2, mem2)
=> (MOVQstore [i-4] {s} p (MOVQload [j-4] {s2} p2 mem) mem)
// Merge load and op
// TODO: add indexed variants?
((ADD|SUB|AND|OR|XOR)Q x l:(MOVQload [off] {sym} ptr mem)) && canMergeLoadClobber(v, l, x) && clobber(l) => ((ADD|SUB|AND|OR|XOR)Qload x [off] {sym} ptr mem)

70
src/cmd/compile/internal/ssa/memcombine.go
View File

@ -499,6 +499,8 @@ func combineStores(root *Value, n int64) bool {
return false
}
if x.Aux.(*types.Type).Size() != size {
// TODO: the constant source and consecutive load source cases
// do not need all the stores to be the same size.
return false
}
base, off := splitPtr(x.Args[0])
@ -572,6 +574,74 @@ func combineStores(root *Value, n int64) bool {
return true
}
// Check for consecutive loads as the source of the stores.
var loadMem *Value
var loadBase BaseAddress
var loadIdx int64
for i := int64(0); i < n; i++ {
load := a[i].store.Args[1]
if load.Op != OpLoad {
loadMem = nil
break
}
if load.Uses != 1 {
loadMem = nil
break
}
if load.Type.IsPtr() {
// Don't combine stores containing a pointer, as we need
// a write barrier for those. This can't currently happen,
// but might in the future if we ever have another
// 8-byte-reg/4-byte-ptr architecture like amd64p32.
loadMem = nil
break
}
mem := load.Args[1]
base, idx := splitPtr(load.Args[0])
if loadMem == nil {
// First one we found
loadMem = mem
loadBase = base
loadIdx = idx
continue
}
if base != loadBase || mem != loadMem {
loadMem = nil
break
}
if idx != loadIdx+(a[i].offset-a[0].offset) {
loadMem = nil
break
}
}
if loadMem != nil {
// Modify the first load to do a larger load instead.
load := a[0].store.Args[1]
switch size * n {
case 2:
load.Type = types.Types[types.TUINT16]
case 4:
load.Type = types.Types[types.TUINT32]
case 8:
load.Type = types.Types[types.TUINT64]
}
// Modify root to do the store.
for i := int64(0); i < n; i++ {
v := a[i].store
if v == root {
v.Aux = load.Type // widen store type
v.SetArg(0, ptr)
v.SetArg(1, load)
v.SetArg(2, mem)
} else {
clobber(v)
v.Type = types.Types[types.TBOOL] // erase memory type
}
}
return true
}
// Check that all the shift/trunc are of the same base value.
shiftBase := getShiftBase(a)
if shiftBase == nil {

129
src/cmd/compile/internal/ssa/rewriteAMD64.go
View File

@ -10181,8 +10181,6 @@ func rewriteValueAMD64_OpAMD64MOVBstore(v *Value) bool {
v_2 := v.Args[2]
v_1 := v.Args[1]
v_0 := v.Args[0]
b := v.Block
typ := &b.Func.Config.Types
// match: (MOVBstore [off] {sym} ptr y:(SETL x) mem)
// cond: y.Uses == 1
// result: (SETLstore [off] {sym} ptr x mem)
@ -10516,47 +10514,6 @@ func rewriteValueAMD64_OpAMD64MOVBstore(v *Value) bool {
v.AddArg3(base, val, mem)
return true
}
// match: (MOVBstore [i] {s} p x1:(MOVBload [j] {s2} p2 mem) mem2:(MOVBstore [i-1] {s} p x2:(MOVBload [j-1] {s2} p2 mem) mem))
// cond: x1.Uses == 1 && x2.Uses == 1 && mem2.Uses == 1 && clobber(x1, x2, mem2)
// result: (MOVWstore [i-1] {s} p (MOVWload [j-1] {s2} p2 mem) mem)
for {
i := auxIntToInt32(v.AuxInt)
s := auxToSym(v.Aux)
p := v_0
x1 := v_1
if x1.Op != OpAMD64MOVBload {
break
}
j := auxIntToInt32(x1.AuxInt)
s2 := auxToSym(x1.Aux)
mem := x1.Args[1]
p2 := x1.Args[0]
mem2 := v_2
if mem2.Op != OpAMD64MOVBstore || auxIntToInt32(mem2.AuxInt) != i-1 || auxToSym(mem2.Aux) != s {
break
}
_ = mem2.Args[2]
if p != mem2.Args[0] {
break
}
x2 := mem2.Args[1]
if x2.Op != OpAMD64MOVBload || auxIntToInt32(x2.AuxInt) != j-1 || auxToSym(x2.Aux) != s2 {
break
}
_ = x2.Args[1]
if p2 != x2.Args[0] || mem != x2.Args[1] || mem != mem2.Args[2] || !(x1.Uses == 1 && x2.Uses == 1 && mem2.Uses == 1 && clobber(x1, x2, mem2)) {
break
}
v.reset(OpAMD64MOVWstore)
v.AuxInt = int32ToAuxInt(i - 1)
v.Aux = symToAux(s)
v0 := b.NewValue0(x2.Pos, OpAMD64MOVWload, typ.UInt16)
v0.AuxInt = int32ToAuxInt(j - 1)
v0.Aux = symToAux(s2)
v0.AddArg2(p2, mem)
v.AddArg3(p, v0, mem)
return true
}
return false
}
func rewriteValueAMD64_OpAMD64MOVBstoreconst(v *Value) bool {
@ -11069,8 +11026,6 @@ func rewriteValueAMD64_OpAMD64MOVLstore(v *Value) bool {
v_2 := v.Args[2]
v_1 := v.Args[1]
v_0 := v.Args[0]
b := v.Block
typ := &b.Func.Config.Types
// match: (MOVLstore [off] {sym} ptr (MOVLQSX x) mem)
// result: (MOVLstore [off] {sym} ptr x mem)
for {
@ -11184,47 +11139,6 @@ func rewriteValueAMD64_OpAMD64MOVLstore(v *Value) bool {
v.AddArg3(base, val, mem)
return true
}
// match: (MOVLstore [i] {s} p x1:(MOVLload [j] {s2} p2 mem) mem2:(MOVLstore [i-4] {s} p x2:(MOVLload [j-4] {s2} p2 mem) mem))
// cond: x1.Uses == 1 && x2.Uses == 1 && mem2.Uses == 1 && clobber(x1, x2, mem2)
// result: (MOVQstore [i-4] {s} p (MOVQload [j-4] {s2} p2 mem) mem)
for {
i := auxIntToInt32(v.AuxInt)
s := auxToSym(v.Aux)
p := v_0
x1 := v_1
if x1.Op != OpAMD64MOVLload {
break
}
j := auxIntToInt32(x1.AuxInt)
s2 := auxToSym(x1.Aux)
mem := x1.Args[1]
p2 := x1.Args[0]
mem2 := v_2
if mem2.Op != OpAMD64MOVLstore || auxIntToInt32(mem2.AuxInt) != i-4 || auxToSym(mem2.Aux) != s {
break
}
_ = mem2.Args[2]
if p != mem2.Args[0] {
break
}
x2 := mem2.Args[1]
if x2.Op != OpAMD64MOVLload || auxIntToInt32(x2.AuxInt) != j-4 || auxToSym(x2.Aux) != s2 {
break
}
_ = x2.Args[1]
if p2 != x2.Args[0] || mem != x2.Args[1] || mem != mem2.Args[2] || !(x1.Uses == 1 && x2.Uses == 1 && mem2.Uses == 1 && clobber(x1, x2, mem2)) {
break
}
v.reset(OpAMD64MOVQstore)
v.AuxInt = int32ToAuxInt(i - 4)
v.Aux = symToAux(s)
v0 := b.NewValue0(x2.Pos, OpAMD64MOVQload, typ.UInt64)
v0.AuxInt = int32ToAuxInt(j - 4)
v0.Aux = symToAux(s2)
v0.AddArg2(p2, mem)
v.AddArg3(p, v0, mem)
return true
}
// match: (MOVLstore {sym} [off] ptr y:(ADDLload x [off] {sym} ptr mem) mem)
// cond: y.Uses==1 && clobber(y)
// result: (ADDLmodify [off] {sym} ptr x mem)
@ -13270,8 +13184,6 @@ func rewriteValueAMD64_OpAMD64MOVWstore(v *Value) bool {
v_2 := v.Args[2]
v_1 := v.Args[1]
v_0 := v.Args[0]
b := v.Block
typ := &b.Func.Config.Types
// match: (MOVWstore [off] {sym} ptr (MOVWQSX x) mem)
// result: (MOVWstore [off] {sym} ptr x mem)
for {
@ -13385,47 +13297,6 @@ func rewriteValueAMD64_OpAMD64MOVWstore(v *Value) bool {
v.AddArg3(base, val, mem)
return true
}
// match: (MOVWstore [i] {s} p x1:(MOVWload [j] {s2} p2 mem) mem2:(MOVWstore [i-2] {s} p x2:(MOVWload [j-2] {s2} p2 mem) mem))
// cond: x1.Uses == 1 && x2.Uses == 1 && mem2.Uses == 1 && clobber(x1, x2, mem2)
// result: (MOVLstore [i-2] {s} p (MOVLload [j-2] {s2} p2 mem) mem)
for {
i := auxIntToInt32(v.AuxInt)
s := auxToSym(v.Aux)
p := v_0
x1 := v_1
if x1.Op != OpAMD64MOVWload {
break
}
j := auxIntToInt32(x1.AuxInt)
s2 := auxToSym(x1.Aux)
mem := x1.Args[1]
p2 := x1.Args[0]
mem2 := v_2
if mem2.Op != OpAMD64MOVWstore || auxIntToInt32(mem2.AuxInt) != i-2 || auxToSym(mem2.Aux) != s {
break
}
_ = mem2.Args[2]
if p != mem2.Args[0] {
break
}
x2 := mem2.Args[1]
if x2.Op != OpAMD64MOVWload || auxIntToInt32(x2.AuxInt) != j-2 || auxToSym(x2.Aux) != s2 {
break
}
_ = x2.Args[1]
if p2 != x2.Args[0] || mem != x2.Args[1] || mem != mem2.Args[2] || !(x1.Uses == 1 && x2.Uses == 1 && mem2.Uses == 1 && clobber(x1, x2, mem2)) {
break
}
v.reset(OpAMD64MOVLstore)
v.AuxInt = int32ToAuxInt(i - 2)
v.Aux = symToAux(s)
v0 := b.NewValue0(x2.Pos, OpAMD64MOVLload, typ.UInt32)
v0.AuxInt = int32ToAuxInt(j - 2)
v0.Aux = symToAux(s2)
v0.AddArg2(p2, mem)
v.AddArg3(p, v0, mem)
return true
}
// match: (MOVWstore [i] {s} p x:(ROLWconst [8] w) mem)
// cond: x.Uses == 1 && buildcfg.GOAMD64 >= 3
// result: (MOVBEWstore [i] {s} p w mem)

22
test/codegen/memcombine.go
View File

@ -836,3 +836,25 @@ func zero_uint64_2(d1, d2 []uint64) {
d1[0], d1[1] = 0, 0 // arm64:"STP",-"MOVB",-"MOVH"
d2[1], d2[0] = 0, 0 // arm64:"STP",-"MOVB",-"MOVH"
}
func loadstore(p, q *[4]uint8) {
// amd64:"MOVL",-"MOVB"
// arm64:"MOVWU",-"MOVBU"
x0, x1, x2, x3 := q[0], q[1], q[2], q[3]
// amd64:"MOVL",-"MOVB"
// arm64:"MOVW",-"MOVB"
p[0], p[1], p[2], p[3] = x0, x1, x2, x3
}
type S1 struct {
a, b int16
}
func loadstore2(p, q *S1) {
// amd64:"MOVL",-"MOVWLZX"
// arm64:"MOVWU",-"MOVH"
a, b := p.a, p.b
// amd64:"MOVL",-"MOVW"
// arm64:"MOVW",-"MOVH"
q.a, q.b = a, b
}