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author | David Chase <drchase@google.com> | 2022-12-19 11:30:07 -0500 |
---|---|---|
committer | Gopher Robot <gobot@golang.org> | 2022-12-28 22:16:43 +0000 |
commit | c1760296e70f6155315d368b8afd35a0e5377dea (patch) | |
tree | a93c22a32fdab51231a863f59f0bae9971b85e17 | |
parent | 24963e5c06e8b90391f46f1bcf825c72342fa0eb (diff) | |
download | go-git-c1760296e70f6155315d368b8afd35a0e5377dea.tar.gz |
[release-branch.go1.19] cmd/compile: sign-extend the 2nd argument of the LoweredAtomicCas32 on loong64,mips64x,riscv64
The function LoweredAtomicCas32 is implemented using the LL-SC instruction pair
on loong64, mips64x, riscv64. However,the LL instruction on loong64, mips64x,
riscv64 is sign-extended, so it is necessary to sign-extend the 2nd parameter
"old" of the LoweredAtomicCas32, so that the instruction BNE after LL can get
the desired result.
The function prototype of LoweredAtomicCas32 in golang:
func Cas32(ptr *uint32, old, new uint32) bool
When using an intrinsify implementation:
case 1: (*ptr) <= 0x80000000 && old < 0x80000000
E.g: (*ptr) = 0x7FFFFFFF, old = Rarg1= 0x7FFFFFFF
After run the instruction "LL (Rarg0), Rtmp": Rtmp = 0x7FFFFFFF
Rtmp ! = Rarg1(old) is false, the result we expect
case 2: (*ptr) >= 0x80000000 && old >= 0x80000000
E.g: (*ptr) = 0x80000000, old = Rarg1= 0x80000000
After run the instruction "LL (Rarg0), Rtmp": Rtmp = 0xFFFFFFFF_80000000
Rtmp ! = Rarg1(old) is true, which we do not expect
When using an non-intrinsify implementation:
Because Rarg1 is loaded from the stack using sign-extended instructions
ld.w, the situation described in Case 2 above does not occur
Benchmarks on linux/loong64:
name old time/op new time/op delta
Cas 50.0ns ± 0% 50.1ns ± 0% ~ (p=1.000 n=1+1)
Cas64 50.0ns ± 0% 50.1ns ± 0% ~ (p=1.000 n=1+1)
Cas-4 56.0ns ± 0% 56.0ns ± 0% ~ (p=1.000 n=1+1)
Cas64-4 56.0ns ± 0% 56.0ns ± 0% ~ (p=1.000 n=1+1)
Benchmarks on Loongson 3A4000 (GOARCH=mips64le, 1.8GHz)
name old time/op new time/op delta
Cas 70.4ns ± 0% 70.3ns ± 0% ~ (p=1.000 n=1+1)
Cas64 70.7ns ± 0% 70.6ns ± 0% ~ (p=1.000 n=1+1)
Cas-4 81.1ns ± 0% 80.8ns ± 0% ~ (p=1.000 n=1+1)
Cas64-4 80.9ns ± 0% 80.9ns ± 0% ~ (p=1.000 n=1+1)
Fixes #57345
Change-Id: I190a7fc648023b15fa392f7fdda5ac18c1561bac
Reviewed-on: https://go-review.googlesource.com/c/go/+/457135
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Wayne Zuo <wdvxdr@golangcn.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/458355
Run-TryBot: David Chase <drchase@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>
-rw-r--r-- | src/cmd/compile/internal/ssa/gen/LOONG64.rules | 3 | ||||
-rw-r--r-- | src/cmd/compile/internal/ssa/gen/MIPS64.rules | 3 | ||||
-rw-r--r-- | src/cmd/compile/internal/ssa/gen/RISCV64.rules | 2 | ||||
-rw-r--r-- | src/cmd/compile/internal/ssa/rewriteLOONG64.go | 24 | ||||
-rw-r--r-- | src/cmd/compile/internal/ssa/rewriteMIPS64.go | 24 | ||||
-rw-r--r-- | src/cmd/compile/internal/ssa/rewriteRISCV64.go | 24 | ||||
-rw-r--r-- | src/runtime/internal/atomic/atomic_test.go | 30 |
7 files changed, 101 insertions, 9 deletions
diff --git a/src/cmd/compile/internal/ssa/gen/LOONG64.rules b/src/cmd/compile/internal/ssa/gen/LOONG64.rules index 3ba25e0a95..e697eea5fb 100644 --- a/src/cmd/compile/internal/ssa/gen/LOONG64.rules +++ b/src/cmd/compile/internal/ssa/gen/LOONG64.rules @@ -392,7 +392,8 @@ (AtomicAdd(32|64) ...) => (LoweredAtomicAdd(32|64) ...) -(AtomicCompareAndSwap(32|64) ...) => (LoweredAtomicCas(32|64) ...) +(AtomicCompareAndSwap32 ptr old new mem) => (LoweredAtomicCas32 ptr (SignExt32to64 old) new mem) +(AtomicCompareAndSwap64 ...) => (LoweredAtomicCas64 ...) // checks (NilCheck ...) => (LoweredNilCheck ...) diff --git a/src/cmd/compile/internal/ssa/gen/MIPS64.rules b/src/cmd/compile/internal/ssa/gen/MIPS64.rules index 17634afd72..a594df2b26 100644 --- a/src/cmd/compile/internal/ssa/gen/MIPS64.rules +++ b/src/cmd/compile/internal/ssa/gen/MIPS64.rules @@ -392,7 +392,8 @@ (AtomicAdd(32|64) ...) => (LoweredAtomicAdd(32|64) ...) -(AtomicCompareAndSwap(32|64) ...) => (LoweredAtomicCas(32|64) ...) +(AtomicCompareAndSwap32 ptr old new mem) => (LoweredAtomicCas32 ptr (SignExt32to64 old) new mem) +(AtomicCompareAndSwap64 ...) => (LoweredAtomicCas64 ...) // checks (NilCheck ...) => (LoweredNilCheck ...) diff --git a/src/cmd/compile/internal/ssa/gen/RISCV64.rules b/src/cmd/compile/internal/ssa/gen/RISCV64.rules index dd20be2aeb..91efe5f3eb 100644 --- a/src/cmd/compile/internal/ssa/gen/RISCV64.rules +++ b/src/cmd/compile/internal/ssa/gen/RISCV64.rules @@ -568,7 +568,7 @@ (AtomicAnd32 ...) => (LoweredAtomicAnd32 ...) -(AtomicCompareAndSwap32 ...) => (LoweredAtomicCas32 ...) +(AtomicCompareAndSwap32 ptr old new mem) => (LoweredAtomicCas32 ptr (SignExt32to64 old) new mem) (AtomicCompareAndSwap64 ...) => (LoweredAtomicCas64 ...) (AtomicExchange32 ...) => (LoweredAtomicExchange32 ...) diff --git a/src/cmd/compile/internal/ssa/rewriteLOONG64.go b/src/cmd/compile/internal/ssa/rewriteLOONG64.go index 3fc10104b9..c783dbfa70 100644 --- a/src/cmd/compile/internal/ssa/rewriteLOONG64.go +++ b/src/cmd/compile/internal/ssa/rewriteLOONG64.go @@ -52,8 +52,7 @@ func rewriteValueLOONG64(v *Value) bool { v.Op = OpLOONG64LoweredAtomicAdd64 return true case OpAtomicCompareAndSwap32: - v.Op = OpLOONG64LoweredAtomicCas32 - return true + return rewriteValueLOONG64_OpAtomicCompareAndSwap32(v) case OpAtomicCompareAndSwap64: v.Op = OpLOONG64LoweredAtomicCas64 return true @@ -695,6 +694,27 @@ func rewriteValueLOONG64_OpAddr(v *Value) bool { return true } } +func rewriteValueLOONG64_OpAtomicCompareAndSwap32(v *Value) bool { + v_3 := v.Args[3] + v_2 := v.Args[2] + v_1 := v.Args[1] + v_0 := v.Args[0] + b := v.Block + typ := &b.Func.Config.Types + // match: (AtomicCompareAndSwap32 ptr old new mem) + // result: (LoweredAtomicCas32 ptr (SignExt32to64 old) new mem) + for { + ptr := v_0 + old := v_1 + new := v_2 + mem := v_3 + v.reset(OpLOONG64LoweredAtomicCas32) + v0 := b.NewValue0(v.Pos, OpSignExt32to64, typ.Int64) + v0.AddArg(old) + v.AddArg4(ptr, v0, new, mem) + return true + } +} func rewriteValueLOONG64_OpAvg64u(v *Value) bool { v_1 := v.Args[1] v_0 := v.Args[0] diff --git a/src/cmd/compile/internal/ssa/rewriteMIPS64.go b/src/cmd/compile/internal/ssa/rewriteMIPS64.go index 1fbd556b5c..6a0fd3ad6e 100644 --- a/src/cmd/compile/internal/ssa/rewriteMIPS64.go +++ b/src/cmd/compile/internal/ssa/rewriteMIPS64.go @@ -52,8 +52,7 @@ func rewriteValueMIPS64(v *Value) bool { v.Op = OpMIPS64LoweredAtomicAdd64 return true case OpAtomicCompareAndSwap32: - v.Op = OpMIPS64LoweredAtomicCas32 - return true + return rewriteValueMIPS64_OpAtomicCompareAndSwap32(v) case OpAtomicCompareAndSwap64: v.Op = OpMIPS64LoweredAtomicCas64 return true @@ -697,6 +696,27 @@ func rewriteValueMIPS64_OpAddr(v *Value) bool { return true } } +func rewriteValueMIPS64_OpAtomicCompareAndSwap32(v *Value) bool { + v_3 := v.Args[3] + v_2 := v.Args[2] + v_1 := v.Args[1] + v_0 := v.Args[0] + b := v.Block + typ := &b.Func.Config.Types + // match: (AtomicCompareAndSwap32 ptr old new mem) + // result: (LoweredAtomicCas32 ptr (SignExt32to64 old) new mem) + for { + ptr := v_0 + old := v_1 + new := v_2 + mem := v_3 + v.reset(OpMIPS64LoweredAtomicCas32) + v0 := b.NewValue0(v.Pos, OpSignExt32to64, typ.Int64) + v0.AddArg(old) + v.AddArg4(ptr, v0, new, mem) + return true + } +} func rewriteValueMIPS64_OpAvg64u(v *Value) bool { v_1 := v.Args[1] v_0 := v.Args[0] diff --git a/src/cmd/compile/internal/ssa/rewriteRISCV64.go b/src/cmd/compile/internal/ssa/rewriteRISCV64.go index 2677e99dc0..bae8f0ce79 100644 --- a/src/cmd/compile/internal/ssa/rewriteRISCV64.go +++ b/src/cmd/compile/internal/ssa/rewriteRISCV64.go @@ -61,8 +61,7 @@ func rewriteValueRISCV64(v *Value) bool { case OpAtomicAnd8: return rewriteValueRISCV64_OpAtomicAnd8(v) case OpAtomicCompareAndSwap32: - v.Op = OpRISCV64LoweredAtomicCas32 - return true + return rewriteValueRISCV64_OpAtomicCompareAndSwap32(v) case OpAtomicCompareAndSwap64: v.Op = OpRISCV64LoweredAtomicCas64 return true @@ -765,6 +764,27 @@ func rewriteValueRISCV64_OpAtomicAnd8(v *Value) bool { return true } } +func rewriteValueRISCV64_OpAtomicCompareAndSwap32(v *Value) bool { + v_3 := v.Args[3] + v_2 := v.Args[2] + v_1 := v.Args[1] + v_0 := v.Args[0] + b := v.Block + typ := &b.Func.Config.Types + // match: (AtomicCompareAndSwap32 ptr old new mem) + // result: (LoweredAtomicCas32 ptr (SignExt32to64 old) new mem) + for { + ptr := v_0 + old := v_1 + new := v_2 + mem := v_3 + v.reset(OpRISCV64LoweredAtomicCas32) + v0 := b.NewValue0(v.Pos, OpSignExt32to64, typ.Int64) + v0.AddArg(old) + v.AddArg4(ptr, v0, new, mem) + return true + } +} func rewriteValueRISCV64_OpAtomicOr8(v *Value) bool { v_2 := v.Args[2] v_1 := v.Args[1] diff --git a/src/runtime/internal/atomic/atomic_test.go b/src/runtime/internal/atomic/atomic_test.go index 2ae60b8507..2427bfd211 100644 --- a/src/runtime/internal/atomic/atomic_test.go +++ b/src/runtime/internal/atomic/atomic_test.go @@ -345,6 +345,36 @@ func TestBitwiseContended(t *testing.T) { } } +func TestCasRel(t *testing.T) { + const _magic = 0x5a5aa5a5 + var x struct { + before uint32 + i uint32 + after uint32 + o uint32 + n uint32 + } + + x.before = _magic + x.after = _magic + for j := 0; j < 32; j += 1 { + x.i = (1 << j) + 0 + x.o = (1 << j) + 0 + x.n = (1 << j) + 1 + if !atomic.CasRel(&x.i, x.o, x.n) { + t.Fatalf("should have swapped %#x %#x", x.o, x.n) + } + + if x.i != x.n { + t.Fatalf("wrong x.i after swap: x.i=%#x x.n=%#x", x.i, x.n) + } + + if x.before != _magic || x.after != _magic { + t.Fatalf("wrong magic: %#x _ %#x != %#x _ %#x", x.before, x.after, _magic, _magic) + } + } +} + func TestStorepNoWB(t *testing.T) { var p [2]*int for i := range p { |