diff options
| -rw-r--r-- | src/cmd/compile/internal/ssa/regalloc.go | 11 | ||||
| -rw-r--r-- | test/fixedbugs/issue22458.go | 26 |
2 files changed, 33 insertions, 4 deletions
diff --git a/src/cmd/compile/internal/ssa/regalloc.go b/src/cmd/compile/internal/ssa/regalloc.go index 137e5fc4c2..a0d69bc65c 100644 --- a/src/cmd/compile/internal/ssa/regalloc.go +++ b/src/cmd/compile/internal/ssa/regalloc.go @@ -1103,12 +1103,15 @@ func (s *regAllocState) regalloc(f *Func) { if v.Op == OpKeepAlive { // Make sure the argument to v is still live here. s.advanceUses(v) - vi := &s.values[v.Args[0].ID] - if vi.spill != nil { + a := v.Args[0] + vi := &s.values[a.ID] + if vi.regs == 0 && !vi.rematerializeable { // Use the spill location. - v.SetArg(0, vi.spill) + // This forces later liveness analysis to make the + // value live at this point. + v.SetArg(0, s.makeSpill(a, b)) } else { - // No need to keep unspilled values live. + // In-register and rematerializeable values are already live. // These are typically rematerializeable constants like nil, // or values of a variable that were modified since the last call. v.Op = OpCopy diff --git a/test/fixedbugs/issue22458.go b/test/fixedbugs/issue22458.go new file mode 100644 index 0000000000..5c89929577 --- /dev/null +++ b/test/fixedbugs/issue22458.go @@ -0,0 +1,26 @@ +// compile + +// Copyright 2017 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. + +// Make sure KeepAlive introduces a use of the spilled variable. + +package main + +import "runtime" + +type node struct { + next *node +} + +var x bool + +func main() { + var head *node + for x { + head = &node{head} + } + + runtime.KeepAlive(head) +} |