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cmd/compile: intrinsify math/bits.Bswap on riscv64

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For riscv64/rva22u64 and above, we can intrinsify math/bits.Bswap
using the REV8 machine instruction.

On a StarFive VisionFive 2 with GORISCV64=rva22u64:

                 │     rb.1     │                rb.2                 │
                 │    sec/op    │   sec/op     vs base                │
ReverseBytes-4     18.790n ± 0%   4.026n ± 0%  -78.57% (p=0.000 n=10)
ReverseBytes16-4    6.710n ± 0%   5.368n ± 0%  -20.00% (p=0.000 n=10)
ReverseBytes32-4   13.420n ± 0%   5.368n ± 0%  -60.00% (p=0.000 n=10)
ReverseBytes64-4   17.450n ± 0%   4.026n ± 0%  -76.93% (p=0.000 n=10)
geomean             13.11n        4.649n       -64.54%

Change-Id: I26eee34270b1721f7304bb1cddb0fda129b20ece
Reviewed-on: https://go-review.googlesource.com/c/go/+/660855
Reviewed-by: Mark Ryan <markdryan@rivosinc.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Meng Zhuo <mengzhuo1203@gmail.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Junyang Shao <shaojunyang@google.com>
This commit is contained in:
Joel Sing 2025-03-20 01:09:23 +11:00
parent 6fc1e34100
commit 90e8b8cdae
8 changed files with 118 additions and 20 deletions
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20
test/codegen/mathbits.go
View file

@ -261,42 +261,46 @@ func Reverse8(n uint8) uint8 {
// ----------------------- //
func ReverseBytes(n uint) uint {
// amd64:"BSWAPQ"
// 386:"BSWAPL"
// s390x:"MOVDBR"
// amd64:"BSWAPQ"
// arm64:"REV"
// loong64:"REVBV"
// riscv64/rva22u64,riscv64/rva23u64:"REV8"
// s390x:"MOVDBR"
return bits.ReverseBytes(n)
}
func ReverseBytes64(n uint64) uint64 {
// amd64:"BSWAPQ"
// 386:"BSWAPL"
// s390x:"MOVDBR"
// amd64:"BSWAPQ"
// arm64:"REV"
// ppc64x/power10: "BRD"
// loong64:"REVBV"
// ppc64x/power10: "BRD"
// riscv64/rva22u64,riscv64/rva23u64:"REV8"
// s390x:"MOVDBR"
return bits.ReverseBytes64(n)
}
func ReverseBytes32(n uint32) uint32 {
// amd64:"BSWAPL"
// 386:"BSWAPL"
// s390x:"MOVWBR"
// amd64:"BSWAPL"
// arm64:"REVW"
// loong64:"REVB2W"
// ppc64x/power10: "BRW"
// riscv64/rva22u64,riscv64/rva23u64:"REV8","SRLI\t\\$32"
// s390x:"MOVWBR"
return bits.ReverseBytes32(n)
}
func ReverseBytes16(n uint16) uint16 {
// amd64:"ROLW"
// arm64:"REV16W",-"UBFX",-"ORR"
// arm/5:"SLL","SRL","ORR"
// arm/6:"REV16"
// arm/7:"REV16"
// arm64:"REV16W",-"UBFX",-"ORR"
// loong64:"REVB2H"
// ppc64x/power10: "BRH"
// riscv64/rva22u64,riscv64/rva23u64:"REV8","SRLI\t\\$48"
return bits.ReverseBytes16(n)
}