cmd/compile: use ANDL for small immediates
We can rewrite ANDQ with an immediate fitting in 32bit with an ANDL, which is shorter to encode.
Looking at Go binary itself, before the change there was:
ANDL: 2337
ANDQ: 4476
After the change:
ANDL: 3790
ANDQ: 3024
So we got rid of 1452 ANDQs
This makes the Linux x86_64 binary 0.03% smaller.
There seems to be an impact on performance.
Intel Cascade Lake benchmarks (with perflock):
name old time/op new time/op delta
BinaryTree17-8 1.91s ± 1% 1.89s ± 1% -1.22% (p=0.000 n=21+18)
Fannkuch11-8 2.34s ± 0% 2.34s ± 0% ~ (p=0.052 n=20+20)
FmtFprintfEmpty-8 27.7ns ± 1% 27.4ns ± 3% ~ (p=0.497 n=21+21)
FmtFprintfString-8 53.2ns ± 0% 51.5ns ± 0% -3.21% (p=0.000 n=20+19)
FmtFprintfInt-8 57.3ns ± 0% 55.7ns ± 0% -2.89% (p=0.000 n=19+19)
FmtFprintfIntInt-8 92.3ns ± 0% 88.4ns ± 1% -4.23% (p=0.000 n=20+21)
FmtFprintfPrefixedInt-8 103ns ± 0% 103ns ± 0% +0.23% (p=0.000 n=20+21)
FmtFprintfFloat-8 147ns ± 0% 148ns ± 0% +0.75% (p=0.000 n=20+21)
FmtManyArgs-8 384ns ± 0% 381ns ± 0% -0.63% (p=0.000 n=21+21)
GobDecode-8 3.86ms ± 1% 3.88ms ± 1% +0.52% (p=0.000 n=20+21)
GobEncode-8 2.77ms ± 1% 2.77ms ± 0% ~ (p=0.078 n=21+21)
Gzip-8 168ms ± 1% 168ms ± 0% +0.24% (p=0.000 n=20+20)
Gunzip-8 25.1ms ± 0% 24.3ms ± 0% -3.03% (p=0.000 n=21+21)
HTTPClientServer-8 61.4µs ± 8% 59.1µs ±10% ~ (p=0.088 n=20+21)
JSONEncode-8 6.86ms ± 0% 6.70ms ± 0% -2.29% (p=0.000 n=20+19)
JSONDecode-8 30.8ms ± 1% 30.6ms ± 1% -0.82% (p=0.000 n=20+20)
Mandelbrot200-8 3.85ms ± 0% 3.85ms ± 0% ~ (p=0.191 n=16+17)
GoParse-8 2.61ms ± 2% 2.60ms ± 1% ~ (p=0.561 n=21+20)
RegexpMatchEasy0_32-8 48.5ns ± 2% 45.9ns ± 3% -5.26% (p=0.000 n=20+21)
RegexpMatchEasy0_1K-8 139ns ± 0% 139ns ± 0% +0.27% (p=0.000 n=18+20)
RegexpMatchEasy1_32-8 41.3ns ± 0% 42.1ns ± 4% +1.95% (p=0.000 n=17+21)
RegexpMatchEasy1_1K-8 216ns ± 2% 216ns ± 0% +0.17% (p=0.020 n=21+19)
RegexpMatchMedium_32-8 790ns ± 7% 803ns ± 8% ~ (p=0.178 n=21+21)
RegexpMatchMedium_1K-8 23.5µs ± 5% 23.7µs ± 5% ~ (p=0.421 n=21+21)
RegexpMatchHard_32-8 1.09µs ± 1% 1.09µs ± 1% -0.53% (p=0.000 n=19+18)
RegexpMatchHard_1K-8 33.0µs ± 0% 33.0µs ± 0% ~ (p=0.610 n=21+20)
Revcomp-8 348ms ± 0% 353ms ± 0% +1.38% (p=0.000 n=17+18)
Template-8 42.0ms ± 1% 41.9ms ± 1% -0.30% (p=0.049 n=20+20)
TimeParse-8 185ns ± 0% 185ns ± 0% ~ (p=0.387 n=20+18)
TimeFormat-8 237ns ± 1% 241ns ± 1% +1.57% (p=0.000 n=21+21)
[Geo mean] 35.4µs 35.2µs -0.66%
name old speed new speed delta
GobDecode-8 199MB/s ± 1% 198MB/s ± 1% -0.52% (p=0.000 n=20+21)
GobEncode-8 277MB/s ± 1% 277MB/s ± 0% ~ (p=0.075 n=21+21)
Gzip-8 116MB/s ± 1% 115MB/s ± 0% -0.25% (p=0.000 n=20+20)
Gunzip-8 773MB/s ± 0% 797MB/s ± 0% +3.12% (p=0.000 n=21+21)
JSONEncode-8 283MB/s ± 0% 290MB/s ± 0% +2.35% (p=0.000 n=20+19)
JSONDecode-8 63.0MB/s ± 1% 63.5MB/s ± 1% +0.82% (p=0.000 n=20+20)
GoParse-8 22.2MB/s ± 2% 22.3MB/s ± 1% ~ (p=0.539 n=21+20)
RegexpMatchEasy0_32-8 660MB/s ± 2% 697MB/s ± 3% +5.57% (p=0.000 n=20+21)
RegexpMatchEasy0_1K-8 7.36GB/s ± 0% 7.34GB/s ± 0% -0.26% (p=0.000 n=18+20)
RegexpMatchEasy1_32-8 775MB/s ± 0% 761MB/s ± 4% -1.88% (p=0.000 n=17+21)
RegexpMatchEasy1_1K-8 4.74GB/s ± 2% 4.74GB/s ± 0% -0.18% (p=0.020 n=21+19)
RegexpMatchMedium_32-8 40.6MB/s ± 7% 39.9MB/s ± 9% ~ (p=0.191 n=21+21)
RegexpMatchMedium_1K-8 43.7MB/s ± 5% 43.2MB/s ± 5% ~ (p=0.435 n=21+21)
RegexpMatchHard_32-8 29.3MB/s ± 1% 29.4MB/s ± 1% +0.53% (p=0.000 n=19+18)
RegexpMatchHard_1K-8 31.0MB/s ± 0% 31.0MB/s ± 0% ~ (p=0.572 n=21+20)
Revcomp-8 730MB/s ± 0% 720MB/s ± 0% -1.36% (p=0.000 n=17+18)
Template-8 46.2MB/s ± 1% 46.3MB/s ± 1% +0.30% (p=0.041 n=20+20)
[Geo mean] 204MB/s 205MB/s +0.30%
Change-Id: Iac75d0ec184a515ce0e65e19559d5fe2e9840514
Reviewed-on: https://go-review.googlesource.com/c/go/+/354970
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
diff --git a/src/cmd/compile/internal/amd64/ssa.go b/src/cmd/compile/internal/amd64/ssa.go
index 7882209..0e74574 100644
--- a/src/cmd/compile/internal/amd64/ssa.go
+++ b/src/cmd/compile/internal/amd64/ssa.go
@@ -618,8 +618,21 @@
p.To.Reg = r
p.SetFrom3Reg(v.Args[0].Reg())
+ case ssa.OpAMD64ANDQconst:
+ asm := v.Op.Asm()
+ // If the constant is positive and fits into 32 bits, use ANDL.
+ // This saves a few bytes of encoding.
+ if 0 <= v.AuxInt && v.AuxInt <= (1<<32-1) {
+ asm = x86.AANDL
+ }
+ p := s.Prog(asm)
+ p.From.Type = obj.TYPE_CONST
+ p.From.Offset = v.AuxInt
+ p.To.Type = obj.TYPE_REG
+ p.To.Reg = v.Reg()
+
case ssa.OpAMD64SUBQconst, ssa.OpAMD64SUBLconst,
- ssa.OpAMD64ANDQconst, ssa.OpAMD64ANDLconst,
+ ssa.OpAMD64ANDLconst,
ssa.OpAMD64ORQconst, ssa.OpAMD64ORLconst,
ssa.OpAMD64XORQconst, ssa.OpAMD64XORLconst,
ssa.OpAMD64SHLQconst, ssa.OpAMD64SHLLconst,
diff --git a/test/codegen/arithmetic.go b/test/codegen/arithmetic.go
index eb95416..8b8c8ed 100644
--- a/test/codegen/arithmetic.go
+++ b/test/codegen/arithmetic.go
@@ -241,7 +241,7 @@
func Pow2Mods(n1 uint, n2 int) (uint, int) {
// 386:"ANDL\t[$]31",-"DIVL"
- // amd64:"ANDQ\t[$]31",-"DIVQ"
+ // amd64:"ANDL\t[$]31",-"DIVQ"
// arm:"AND\t[$]31",-".*udiv"
// arm64:"AND\t[$]31",-"UDIV"
// ppc64:"ANDCC\t[$]31"
@@ -452,7 +452,7 @@
func LenMod1(a []int) int {
// 386:"ANDL\t[$]1023"
- // amd64:"ANDQ\t[$]1023"
+ // amd64:"ANDL\t[$]1023"
// arm64:"AND\t[$]1023",-"SDIV"
// arm/6:"AND",-".*udiv"
// arm/7:"BFC",-".*udiv",-"AND"
@@ -463,7 +463,7 @@
func LenMod2(s string) int {
// 386:"ANDL\t[$]2047"
- // amd64:"ANDQ\t[$]2047"
+ // amd64:"ANDL\t[$]2047"
// arm64:"AND\t[$]2047",-"SDIV"
// arm/6:"AND",-".*udiv"
// arm/7:"BFC",-".*udiv",-"AND"
@@ -484,7 +484,7 @@
func CapMod(a []int) int {
// 386:"ANDL\t[$]4095"
- // amd64:"ANDQ\t[$]4095"
+ // amd64:"ANDL\t[$]4095"
// arm64:"AND\t[$]4095",-"SDIV"
// arm/6:"AND",-".*udiv"
// arm/7:"BFC",-".*udiv",-"AND"
diff --git a/test/codegen/bits.go b/test/codegen/bits.go
index 8e973d5..e7826b8 100644
--- a/test/codegen/bits.go
+++ b/test/codegen/bits.go
@@ -332,7 +332,7 @@
}
func bitSetTest(x int) bool {
- // amd64:"ANDQ\t[$]9, AX"
+ // amd64:"ANDL\t[$]9, AX"
// amd64:"CMPQ\tAX, [$]9"
return x&9 == 9
}
diff --git a/test/codegen/bool.go b/test/codegen/bool.go
index 929b1b4..a324233 100644
--- a/test/codegen/bool.go
+++ b/test/codegen/bool.go
@@ -27,7 +27,7 @@
}
func convertNeq0Q(x uint64, c bool) bool {
- // amd64:"ANDQ\t[$]1",-"SETB"
+ // amd64:"ANDL\t[$]1",-"SETB"
b := x&1 != 0
return c && b
}
