diff options
| -rw-r--r-- | src/cmd/compile/internal/ssa/loopbce.go | 7 | ||||
| -rw-r--r-- | test/fixedbugs/issue63955.go | 22 |
2 files changed, 29 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/loopbce.go b/src/cmd/compile/internal/ssa/loopbce.go index d92566f2d3..696930fed8 100644 --- a/src/cmd/compile/internal/ssa/loopbce.go +++ b/src/cmd/compile/internal/ssa/loopbce.go @@ -130,6 +130,13 @@ func findIndVar(f *Func) []indVar { less = false } + if ind.Block != b { + // TODO: Could be extended to include disjointed loop headers. + // I don't think this is causing missed optimizations in real world code often. + // See https://go.dev/issue/63955 + continue + } + // Expect the increment to be a nonzero constant. if inc.Op != OpConst64 { continue diff --git a/test/fixedbugs/issue63955.go b/test/fixedbugs/issue63955.go new file mode 100644 index 0000000000..258e874220 --- /dev/null +++ b/test/fixedbugs/issue63955.go @@ -0,0 +1,22 @@ +// compile + +// Copyright 2023 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 j + +func f(try func() int, shouldInc func() bool, N func(int) int) { + var n int +loop: // we want to have 3 preds here, the function entry and both gotos + if v := try(); v == 42 || v == 1337 { // the two || are to trick findIndVar + if n < 30 { // this aims to be the matched block + if shouldInc() { + n++ + goto loop + } + n = N(n) // try to prevent some block joining + goto loop + } + } +} |