From 2cdcc4150bc577e0b40a9cedaaa7c8301f2860cd Mon Sep 17 00:00:00 2001 From: Meng Zhuo Date: Fri, 14 Nov 2025 12:47:35 +0800 Subject: cmd/compile: fold negation into multiplication MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit goos: linux goarch: riscv64 pkg: cmd/compile/internal/test cpu: Spacemit(R) X60 │ /root/mul.base.log │ /root/mul.new.log │ │ sec/op │ sec/op vs base │ MulNeg 6.426µ ± 0% 4.501µ ± 0% -29.96% (p=0.000 n=10) Mul2Neg 9.000µ ± 0% 6.431µ ± 0% -28.54% (p=0.000 n=10) Mul2 1.263µ ± 0% 1.263µ ± 0% ~ (p=1.000 n=10) MulNeg2 1.577µ ± 0% 1.577µ ± 0% ~ (p=0.211 n=10) geomean 3.276µ 2.756µ -15.89% goos: linux goarch: amd64 pkg: cmd/compile/internal/test cpu: AMD EPYC 7532 32-Core Processor │ /root/base │ /root/new │ │ sec/op │ sec/op vs base │ MulNeg 691.9n ± 1% 319.4n ± 0% -53.83% (p=0.000 n=10) Mul2Neg 630.0n ± 0% 629.6n ± 0% -0.07% (p=0.000 n=10) Mul2 438.1n ± 0% 438.1n ± 0% ~ (p=0.728 n=10) MulNeg2 439.3n ± 0% 439.4n ± 0% ~ (p=0.656 n=10) geomean 538.2n 443.6n -17.58% Change-Id: Ice8e6c8d1e8e3009ba8a0b1b689205174e199019 Reviewed-on: https://go-review.googlesource.com/c/go/+/720180 Reviewed-by: abner chenc Reviewed-by: Keith Randall Reviewed-by: Junyang Shao Reviewed-by: Joel Sing Reviewed-by: Keith Randall LUCI-TryBot-Result: Go LUCI Auto-Submit: Keith Randall --- src/cmd/compile/internal/ssa/_gen/LOONG64.rules | 3 --- src/cmd/compile/internal/ssa/_gen/generic.rules | 7 ++++++- 2 files changed, 6 insertions(+), 4 deletions(-) (limited to 'src/cmd/compile/internal/ssa/_gen') diff --git a/src/cmd/compile/internal/ssa/_gen/LOONG64.rules b/src/cmd/compile/internal/ssa/_gen/LOONG64.rules index 9691296043..2beba0b1c5 100644 --- a/src/cmd/compile/internal/ssa/_gen/LOONG64.rules +++ b/src/cmd/compile/internal/ssa/_gen/LOONG64.rules @@ -743,9 +743,6 @@ (MULV x (MOVVconst [c])) && canMulStrengthReduce(config, c) => {mulStrengthReduce(v, x, c)} -(MULV (NEGV x) (MOVVconst [c])) => (MULV x (MOVVconst [-c])) -(MULV (NEGV x) (NEGV y)) => (MULV x y) - (ADDV x0 x1:(SLLVconst [c] y)) && x1.Uses == 1 && c > 0 && c <= 4 => (ADDshiftLLV x0 y [c]) // fold constant in ADDshift op diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules index 6efead03ad..e09cd31c31 100644 --- a/src/cmd/compile/internal/ssa/_gen/generic.rules +++ b/src/cmd/compile/internal/ssa/_gen/generic.rules @@ -195,6 +195,11 @@ // Convert x * -1 to -x. (Mul(8|16|32|64) (Const(8|16|32|64) [-1]) x) => (Neg(8|16|32|64) x) +// Convert -x * c to x * -c +(Mul(8|16|32|64) (Const(8|16|32|64) [c]) (Neg(8|16|32|64) x)) => (Mul(8|16|32|64) x (Const(8|16|32|64) [-c])) + +(Mul(8|16|32|64) (Neg(8|16|32|64) x) (Neg(8|16|32|64) y)) => (Mul(8|16|32|64) x y) + // DeMorgan's Laws (And(8|16|32|64) (Com(8|16|32|64) x) (Com(8|16|32|64) y)) => (Com(8|16|32|64) (Or(8|16|32|64) x y)) (Or(8|16|32|64) (Com(8|16|32|64) x) (Com(8|16|32|64) y)) => (Com(8|16|32|64) (And(8|16|32|64) x y)) @@ -2228,4 +2233,4 @@ (Neq(64|32|16) (SignExt8to(64|32|16) (CvtBoolToUint8 x)) (Const(64|32|16) [0])) => x (Neq(64|32|16) (SignExt8to(64|32|16) (CvtBoolToUint8 x)) (Const(64|32|16) [1])) => (Not x) (Eq(64|32|16) (SignExt8to(64|32|16) (CvtBoolToUint8 x)) (Const(64|32|16) [1])) => x -(Eq(64|32|16) (SignExt8to(64|32|16) (CvtBoolToUint8 x)) (Const(64|32|16) [0])) => (Not x) \ No newline at end of file +(Eq(64|32|16) (SignExt8to(64|32|16) (CvtBoolToUint8 x)) (Const(64|32|16) [0])) => (Not x) -- cgit v1.3-6-g1900