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cmd/compile: replace ANDL with MOV?ZX

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According to "Intel 64 and IA-32 Architectures Optimization Reference
Manual" Section: "3.5.1.13 Zero-Latency MOV Instructions"
MOV?ZX instructions have zero latency on newer processors.

during make.bash:
(ANDLconst [0xFF] x) -> (MOVBQZX x)
applies 422 times
(ANDLconst [0xFFFF] x) -> (MOVWQZX x)
applies 114 times

Updates #15105

Change-Id: I10933af599de3c26449c52f4b5cd859331028f39
Reviewed-on: https://go-review.googlesource.com/31639
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
This commit is contained in:
Martin Möhrmann 2016-10-22 15:43:23 +02:00 committed by Martin Möhrmann
parent 9ac60181e2
commit 7ff0c8267f
2 changed files with 27 additions and 1 deletions
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4
src/cmd/compile/internal/ssa/gen/AMD64.rules
View File

@ -631,7 +631,9 @@
(CMPB x (MOVLconst [c])) -> (CMPBconst x [int64(int8(c))])
(CMPB (MOVLconst [c]) x) -> (InvertFlags (CMPBconst x [int64(int8(c))]))
// Using MOVBQZX instead of ANDQ is cheaper.
// Using MOVZX instead of AND is cheaper.
(ANDLconst [0xFF] x) -> (MOVBQZX x)
(ANDLconst [0xFFFF] x) -> (MOVWQZX x)
(ANDQconst [0xFF] x) -> (MOVBQZX x)
(ANDQconst [0xFFFF] x) -> (MOVWQZX x)
(ANDQconst [0xFFFFFFFF] x) -> (MOVLQZX x)

24
src/cmd/compile/internal/ssa/rewriteAMD64.go
View File

@ -1409,6 +1409,30 @@ func rewriteValueAMD64_OpAMD64ANDLconst(v *Value, config *Config) bool {
v.AddArg(x)
return true
}
// match: (ANDLconst [0xFF] x)
// cond:
// result: (MOVBQZX x)
for {
if v.AuxInt != 0xFF {
break
}
x := v.Args[0]
v.reset(OpAMD64MOVBQZX)
v.AddArg(x)
return true
}
// match: (ANDLconst [0xFFFF] x)
// cond:
// result: (MOVWQZX x)
for {
if v.AuxInt != 0xFFFF {
break
}
x := v.Args[0]
v.reset(OpAMD64MOVWQZX)
v.AddArg(x)
return true
}
// match: (ANDLconst [c] _)
// cond: int32(c)==0
// result: (MOVLconst [0])