diff options
| -rw-r--r-- | src/cmd/compile/internal/ssa/loopbce.go | 6 | ||||
| -rw-r--r-- | test/fixedbugs/issue26043.go | 32 |
2 files changed, 37 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/ssa/loopbce.go b/src/cmd/compile/internal/ssa/loopbce.go index 0c09de0bfc..2ab05711ad 100644 --- a/src/cmd/compile/internal/ssa/loopbce.go +++ b/src/cmd/compile/internal/ssa/loopbce.go @@ -1,3 +1,7 @@ +// Copyright 2018 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. + package ssa import "fmt" @@ -154,7 +158,7 @@ nextb: // if the increment is ±1 or when the limits are constants. if inc.AuxInt != 1 && inc.AuxInt != -1 { ok := false - if min.Op == OpConst64 && max.Op == OpConst64 { + if min.Op == OpConst64 && max.Op == OpConst64 && inc.AuxInt != 0 { if max.AuxInt > min.AuxInt && max.AuxInt%inc.AuxInt == min.AuxInt%inc.AuxInt { // handle overflow ok = true } diff --git a/test/fixedbugs/issue26043.go b/test/fixedbugs/issue26043.go new file mode 100644 index 0000000000..fe32947b07 --- /dev/null +++ b/test/fixedbugs/issue26043.go @@ -0,0 +1,32 @@ +// compile + +// Copyright 2018 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. + +// This program results in a loop inferred to increment +// j by 0, causing bounds check elimination to attempt +// something%0, which panics (in the bug). + +package q + +func f() { + var s1 string + var b bool + if b { + b = !b + s1 += "a" + } + + var s2 string + var i, j int + if (s1 <= "") || (s2 >= "") { + j = len(s1[:6]) + } else { + i = len("b") + } + + for j < 0 { + j += i + } +} |