diff options
| -rw-r--r-- | src/cmd/compile/internal/mips64/ssa.go | 5 | ||||
| -rw-r--r-- | test/fixedbugs/issue50671.go | 35 |
2 files changed, 39 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/mips64/ssa.go b/src/cmd/compile/internal/mips64/ssa.go index 2727c4d8a83..b0e0165ad87 100644 --- a/src/cmd/compile/internal/mips64/ssa.go +++ b/src/cmd/compile/internal/mips64/ssa.go @@ -321,7 +321,10 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) { for a.Op == ssa.OpCopy || a.Op == ssa.OpMIPS64MOVVreg { a = a.Args[0] } - if a.Op == ssa.OpLoadReg { + if a.Op == ssa.OpLoadReg && mips.REG_R0 <= a.Reg() && a.Reg() <= mips.REG_R31 { + // LoadReg from a narrower type does an extension, except loading + // to a floating point register. So only eliminate the extension + // if it is loaded to an integer register. t := a.Type switch { case v.Op == ssa.OpMIPS64MOVBreg && t.Size() == 1 && t.IsSigned(), diff --git a/test/fixedbugs/issue50671.go b/test/fixedbugs/issue50671.go new file mode 100644 index 00000000000..9f4742bfcdc --- /dev/null +++ b/test/fixedbugs/issue50671.go @@ -0,0 +1,35 @@ +// run + +// Copyright 2022 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Issue 50671: sign extension eliminated incorrectly on MIPS64. + +package main + +//go:noinline +func F(x int32) (float64, int64) { + a := float64(x) + b := int64(x) + return a, b +} + +var a, b, c float64 + +// Poison some floating point registers with non-zero high bits. +// +//go:noinline +func poison(x float64) { + a = x - 123.45 + b = a * 1.2 + c = b + 3.4 +} + +func main() { + poison(333.3) + _, b := F(123) + if b != 123 { + panic("FAIL") + } +} |