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cmd/compile: intrinsify math/bits/ReverseBytes{32|64} for 386

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The BSWAPL instruction is supported in i486 and newer.
https://github.com/golang/go/wiki/MinimumRequirements#386 says we
support "All Pentium MMX or later". The Pentium is also referred to as
i586, so that we are safe with these instructions.

Change-Id: I6dea1f9d864a45bb07c8f8f35a81cfe16cca216c
Reviewed-on: https://go-review.googlesource.com/c/go/+/465515
Run-TryBot: Wayne Zuo <wdvxdr@golangcn.org>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@google.com>
This commit is contained in:
Wayne Zuo 2023-02-06 21:21:52 +08:00
parent abd55d8483
commit d7ac5d1480
2 changed files with 6 additions and 3 deletions
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6
src/cmd/compile/internal/ssagen/ssa.go
View file

@ -4000,10 +4000,10 @@ func InitTables() {
},
sys.ARM64, sys.PPC64)
/* Use only on Power10 as the new byte reverse instructions that Power10 provide
make it worthwhile as an intrinsic */
brev_arch := []sys.ArchFamily{sys.AMD64, sys.ARM64, sys.ARM, sys.S390X}
brev_arch := []sys.ArchFamily{sys.AMD64, sys.I386, sys.ARM64, sys.ARM, sys.S390X}
if buildcfg.GOPPC64 >= 10 {
// Use only on Power10 as the new byte reverse instructions that Power10 provide
// make it worthwhile as an intrinsic
brev_arch = append(brev_arch, sys.PPC64)
}
/******** runtime/internal/sys ********/

3
test/codegen/mathbits.go
View file

@ -189,6 +189,7 @@ func OnesCount8(n uint8) int {
func ReverseBytes(n uint) uint {
// amd64:"BSWAPQ"
// 386:"BSWAPL"
// s390x:"MOVDBR"
// arm64:"REV"
return bits.ReverseBytes(n)
@ -196,6 +197,7 @@ func ReverseBytes(n uint) uint {
func ReverseBytes64(n uint64) uint64 {
// amd64:"BSWAPQ"
// 386:"BSWAPL"
// s390x:"MOVDBR"
// arm64:"REV"
// ppc64x/power10: "BRD"
@ -204,6 +206,7 @@ func ReverseBytes64(n uint64) uint64 {
func ReverseBytes32(n uint32) uint32 {
// amd64:"BSWAPL"
// 386:"BSWAPL"
// s390x:"MOVWBR"
// arm64:"REVW"
// ppc64x/power10: "BRW"