From b6a6847b2f33dc8fb231c78cc4d807eaf10a133a Mon Sep 17 00:00:00 2001 From: Joel Sing Date: Tue, 30 Aug 2022 06:32:09 +1000 Subject: [PATCH] cmd/compile: avoid zero extension after properly typed atomic operation on riscv64 LoweredAtomicLoad8 is implemented using MOVBU, hence it is already zero extended. LoweredAtomicCas32 and LoweredAtomicCas64 return a properly typed boolean. Change-Id: Ie0acbaa19403d59c7e5f76d060cc13ee51eb7834 Reviewed-on: https://go-review.googlesource.com/c/go/+/428214 Reviewed-by: Cherry Mui Reviewed-by: Michael Knyszek TryBot-Result: Gopher Robot Run-TryBot: Joel Sing --- .../compile/internal/ssa/gen/RISCV64.rules | 5 +++ .../compile/internal/ssa/rewriteRISCV64.go | 45 +++++++++++++++++++ 2 files changed, 50 insertions(+) diff --git a/src/cmd/compile/internal/ssa/gen/RISCV64.rules b/src/cmd/compile/internal/ssa/gen/RISCV64.rules index 0207fb45d6..385f004b22 100644 --- a/src/cmd/compile/internal/ssa/gen/RISCV64.rules +++ b/src/cmd/compile/internal/ssa/gen/RISCV64.rules @@ -686,6 +686,11 @@ (MOVWUreg x:(MOVHUload _ _)) => (MOVDreg x) (MOVWUreg x:(MOVWUload _ _)) => (MOVDreg x) +// Avoid zero extension after properly typed atomic operation. +(MOVBUreg x:(Select0 (LoweredAtomicLoad8 _ _))) => (MOVDreg x) +(MOVBUreg x:(Select0 (LoweredAtomicCas32 _ _ _ _))) => (MOVDreg x) +(MOVBUreg x:(Select0 (LoweredAtomicCas64 _ _ _ _))) => (MOVDreg x) + // Fold double extensions. (MOVBreg x:(MOVBreg _)) => (MOVDreg x) (MOVHreg x:(MOVBreg _)) => (MOVDreg x) diff --git a/src/cmd/compile/internal/ssa/rewriteRISCV64.go b/src/cmd/compile/internal/ssa/rewriteRISCV64.go index 908456b0aa..ac0770639e 100644 --- a/src/cmd/compile/internal/ssa/rewriteRISCV64.go +++ b/src/cmd/compile/internal/ssa/rewriteRISCV64.go @@ -3609,6 +3609,51 @@ func rewriteValueRISCV64_OpRISCV64MOVBUreg(v *Value) bool { v.AddArg(x) return true } + // match: (MOVBUreg x:(Select0 (LoweredAtomicLoad8 _ _))) + // result: (MOVDreg x) + for { + x := v_0 + if x.Op != OpSelect0 { + break + } + x_0 := x.Args[0] + if x_0.Op != OpRISCV64LoweredAtomicLoad8 { + break + } + v.reset(OpRISCV64MOVDreg) + v.AddArg(x) + return true + } + // match: (MOVBUreg x:(Select0 (LoweredAtomicCas32 _ _ _ _))) + // result: (MOVDreg x) + for { + x := v_0 + if x.Op != OpSelect0 { + break + } + x_0 := x.Args[0] + if x_0.Op != OpRISCV64LoweredAtomicCas32 { + break + } + v.reset(OpRISCV64MOVDreg) + v.AddArg(x) + return true + } + // match: (MOVBUreg x:(Select0 (LoweredAtomicCas64 _ _ _ _))) + // result: (MOVDreg x) + for { + x := v_0 + if x.Op != OpSelect0 { + break + } + x_0 := x.Args[0] + if x_0.Op != OpRISCV64LoweredAtomicCas64 { + break + } + v.reset(OpRISCV64MOVDreg) + v.AddArg(x) + return true + } // match: (MOVBUreg x:(MOVBUreg _)) // result: (MOVDreg x) for { -- 2.48.1