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Josh Bleecher Snyder authored
Use SETcc instructions instead of Jcc to generate boolean values. This generates shorter, jump-free code, which may in turn enable other peephole optimizations. For example, given func f(i, j int) bool { return i == j } Before "".f t=1 size=32 value=0 args=0x18 locals=0x0 0x0000 00000 (x.go:3) TEXT "".f(SB), $0-24 0x0000 00000 (x.go:3) FUNCDATA $0, gclocals·b4c25e9b09fd0cf9bb429dcefe91c353(SB) 0x0000 00000 (x.go:3) FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB) 0x0000 00000 (x.go:4) MOVQ "".i+8(FP), BX 0x0005 00005 (x.go:4) MOVQ "".j+16(FP), BP 0x000a 00010 (x.go:4) CMPQ BX, BP 0x000d 00013 (x.go:4) JEQ 21 0x000f 00015 (x.go:4) MOVB $0, "".~r2+24(FP) 0x0014 00020 (x.go:4) RET 0x0015 00021 (x.go:4) MOVB $1, "".~r2+24(FP) 0x001a 00026 (x.go:4) JMP 20 After "".f t=1 size=32 value=0 args=0x18 locals=0x0 0x0000 00000 (x.go:3) TEXT "".f(SB), $0-24 0x0000 00000 (x.go:3) FUNCDATA $0, gclocals·b4c25e9b09fd0cf9bb429dcefe91c353(SB) 0x0000 00000 (x.go:3) FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB) 0x0000 00000 (x.go:4) MOVQ "".i+8(FP), BX 0x0005 00005 (x.go:4) MOVQ "".j+16(FP), BP 0x000a 00010 (x.go:4) CMPQ BX, BP 0x000d 00013 (x.go:4) SETEQ "".~r2+24(FP) 0x0012 00018 (x.go:4) RET regexp benchmarks, best of 12 runs: benchmark old ns/op new ns/op delta BenchmarkNotOnePassShortB 782 733 -6.27% BenchmarkLiteral 180 171 -5.00% BenchmarkNotLiteral 2855 2721 -4.69% BenchmarkMatchHard_32 2672 2557 -4.30% BenchmarkMatchHard_1K 80182 76732 -4.30% BenchmarkMatchEasy1_32M 76440180 73304748 -4.10% BenchmarkMatchEasy1_32K 68798 66350 -3.56% BenchmarkAnchoredLongMatch 482 465 -3.53% BenchmarkMatchEasy1_1M 2373042 2292692 -3.39% BenchmarkReplaceAll 2776 2690 -3.10% BenchmarkNotOnePassShortA 1397 1360 -2.65% BenchmarkMatchClass_InRange 3842 3742 -2.60% BenchmarkMatchEasy0_32 125 122 -2.40% BenchmarkMatchEasy0_32K 11414 11164 -2.19% BenchmarkMatchEasy0_1K 668 654 -2.10% BenchmarkAnchoredShortMatch 260 255 -1.92% BenchmarkAnchoredLiteralShortNonMatch 164 161 -1.83% BenchmarkOnePassShortB 623 612 -1.77% BenchmarkOnePassShortA 801 788 -1.62% BenchmarkMatchClass 4094 4033 -1.49% BenchmarkMatchEasy0_32M 14078800 13890704 -1.34% BenchmarkMatchHard_32K 4095844 4045820 -1.22% BenchmarkMatchEasy1_1K 1663 1643 -1.20% BenchmarkMatchHard_1M 131261708 129708215 -1.18% BenchmarkMatchHard_32M 4210112412 4169292003 -0.97% BenchmarkMatchMedium_32K 2460752 2438611 -0.90% BenchmarkMatchEasy0_1M 422914 419672 -0.77% BenchmarkMatchMedium_1M 78581121 78040160 -0.69% BenchmarkMatchMedium_32M 2515287278 2498464906 -0.67% BenchmarkMatchMedium_32 1754 1746 -0.46% BenchmarkMatchMedium_1K 52105 52106 +0.00% BenchmarkAnchoredLiteralLongNonMatch 185 185 +0.00% BenchmarkMatchEasy1_32 107 107 +0.00% BenchmarkOnePassLongNotPrefix 505 505 +0.00% BenchmarkOnePassLongPrefix 147 147 +0.00% The godoc binary is ~0.12% smaller after this CL. Updates #5729. toolstash -cmp passes for all architectures other than amd64 and amd64p32. Other architectures can be done in follow-up CLs. Change-Id: I0e167e259274b722958567fc0af83a17ca002da7 Reviewed-on: https://go-review.googlesource.com/2284Reviewed-by:Russ Cox <rsc@golang.org>
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