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cmd/compile: don't combine 64-bit loads/stores on amd64

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This causes a performance regression for some calls.

Fixes #23424.
Updates #6853.

Change-Id: Id1db652d5aca0ce631a3417c0c056d6637fefa9e
Reviewed-on: https://go-review.googlesource.com/88135
Run-TryBot: Caleb Spare <cespare@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Caleb Spare 2018-01-17 12:13:45 -08:00 committed by Keith Randall
parent bd89333426
commit 67fdf587dc
3 changed files with 1 additions and 99 deletions
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8
src/cmd/compile/internal/gc/asm_test.go
View File

@ -1051,14 +1051,6 @@ var linuxAMD64Tests = []*asmTest{
`,
pos: []string{"\tMOVQ\t"},
},
{
fn: `
func f76(a, b uint64) (uint64,uint64) {
return f76(f76(a,b))
}
`,
pos: []string{"\tMOVUPS\t"},
},
// Make sure we don't put pointers in SSE registers across safe points.
{
fn: `

16
src/cmd/compile/internal/ssa/gen/AMD64.rules
View File

@ -2487,22 +2487,6 @@
&& clobber(mem2)
-> (MOVQstore [i-4] {s} p (MOVQload [j-4] {s2} p2 mem) mem)
// This is somewhat tricky. There may be pointers in SSE registers due to rule below.
// However those register shouldn't live across GC safepoint.
(MOVQstore [i] {s} p
x1:(MOVQload [j] {s2} p2 mem)
mem2:(MOVQstore [i-8] {s} p
x2:(MOVQload [j-8] {s2} p2 mem) mem))
&& x1.Uses == 1
&& x2.Uses == 1
&& mem2.Uses == 1
&& config.useSSE
&& clobber(x1)
&& clobber(x2)
&& clobber(mem2)
-> (MOVOstore [i-8] {s} p (MOVOload [j-8] {s2} p2 mem) mem)
// amd64p32 rules
// same as the rules above, but with 32 instead of 64 bit pointer arithmetic.
// LEAQ,ADDQ -> LEAL,ADDL

76
src/cmd/compile/internal/ssa/rewriteAMD64.go
View File

@ -158,7 +158,7 @@ func rewriteValueAMD64(v *Value) bool {
case OpAMD64MOVQloadidx8:
return rewriteValueAMD64_OpAMD64MOVQloadidx8_0(v)
case OpAMD64MOVQstore:
return rewriteValueAMD64_OpAMD64MOVQstore_0(v) || rewriteValueAMD64_OpAMD64MOVQstore_10(v)
return rewriteValueAMD64_OpAMD64MOVQstore_0(v)
case OpAMD64MOVQstoreconst:
return rewriteValueAMD64_OpAMD64MOVQstoreconst_0(v)
case OpAMD64MOVQstoreconstidx1:
@ -10124,10 +10124,6 @@ func rewriteValueAMD64_OpAMD64MOVQloadidx8_0(v *Value) bool {
return false
}
func rewriteValueAMD64_OpAMD64MOVQstore_0(v *Value) bool {
b := v.Block
_ = b
config := b.Func.Config
_ = config
// match: (MOVQstore [off1] {sym} (ADDQconst [off2] ptr) val mem)
// cond: is32Bit(off1+off2)
// result: (MOVQstore [off1+off2] {sym} ptr val mem)
@ -10293,73 +10289,6 @@ func rewriteValueAMD64_OpAMD64MOVQstore_0(v *Value) bool {
v.AddArg(mem)
return true
}
// match: (MOVQstore [i] {s} p x1:(MOVQload [j] {s2} p2 mem) mem2:(MOVQstore [i-8] {s} p x2:(MOVQload [j-8] {s2} p2 mem) mem))
// cond: x1.Uses == 1 && x2.Uses == 1 && mem2.Uses == 1 && config.useSSE && clobber(x1) && clobber(x2) && clobber(mem2)
// result: (MOVOstore [i-8] {s} p (MOVOload [j-8] {s2} p2 mem) mem)
for {
i := v.AuxInt
s := v.Aux
_ = v.Args[2]
p := v.Args[0]
x1 := v.Args[1]
if x1.Op != OpAMD64MOVQload {
break
}
j := x1.AuxInt
s2 := x1.Aux
_ = x1.Args[1]
p2 := x1.Args[0]
mem := x1.Args[1]
mem2 := v.Args[2]
if mem2.Op != OpAMD64MOVQstore {
break
}
if mem2.AuxInt != i-8 {
break
}
if mem2.Aux != s {
break
}
_ = mem2.Args[2]
if p != mem2.Args[0] {
break
}
x2 := mem2.Args[1]
if x2.Op != OpAMD64MOVQload {
break
}
if x2.AuxInt != j-8 {
break
}
if x2.Aux != s2 {
break
}
_ = x2.Args[1]
if p2 != x2.Args[0] {
break
}
if mem != x2.Args[1] {
break
}
if mem != mem2.Args[2] {
break
}
if !(x1.Uses == 1 && x2.Uses == 1 && mem2.Uses == 1 && config.useSSE && clobber(x1) && clobber(x2) && clobber(mem2)) {
break
}
v.reset(OpAMD64MOVOstore)
v.AuxInt = i - 8
v.Aux = s
v.AddArg(p)
v0 := b.NewValue0(v.Pos, OpAMD64MOVOload, types.TypeInt128)
v0.AuxInt = j - 8
v0.Aux = s2
v0.AddArg(p2)
v0.AddArg(mem)
v.AddArg(v0)
v.AddArg(mem)
return true
}
// match: (MOVQstore [off1] {sym1} (LEAL [off2] {sym2} base) val mem)
// cond: canMergeSym(sym1, sym2) && is32Bit(off1+off2)
// result: (MOVQstore [off1+off2] {mergeSym(sym1,sym2)} base val mem)
@ -10452,9 +10381,6 @@ func rewriteValueAMD64_OpAMD64MOVQstore_0(v *Value) bool {
v.AddArg(mem)
return true
}
return false
}
func rewriteValueAMD64_OpAMD64MOVQstore_10(v *Value) bool {
// match: (MOVQstore [off] {sym} ptr (MOVQf2i val) mem)
// cond:
// result: (MOVSDstore [off] {sym} ptr val mem)