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| author | Cuong Manh Le <cuong.manhle.vn@gmail.com> | 2026-04-13 15:53:10 +0700 |
|---|---|---|
| committer | Gopher Robot <gobot@golang.org> | 2026-04-13 11:56:30 -0700 |
| commit | e7c75c3ae80338a635051770052652870679aaf5 (patch) | |
| tree | 666a920f7ce7c9c3556434ef426bc2a5407c4b01 /src/cmd/compile | |
| parent | 82c5ec222aa61c24481bee237102b605bd62c292 (diff) | |
| download | go-e7c75c3ae80338a635051770052652870679aaf5.tar.xz | |
cmd/compile: handle min integer step in loop
Since negating min int will overflows back to itself, causing a panic
inside subWillUnderflow check.
Fixes #78641
Change-Id: Ibbf2fa3228b9890a1a76ac6f4ff504b7e125b29f
Reviewed-on: https://go-review.googlesource.com/c/go/+/766260
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Jorropo <jorropo.pgm@gmail.com>
Reviewed-by: Keith Randall <khr@google.com>
Diffstat (limited to 'src/cmd/compile')
| -rw-r--r-- | src/cmd/compile/internal/ssa/loopbce.go | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/loopbce.go b/src/cmd/compile/internal/ssa/loopbce.go index 0d3130fe9a..127018dfb0 100644 --- a/src/cmd/compile/internal/ssa/loopbce.go +++ b/src/cmd/compile/internal/ssa/loopbce.go @@ -159,6 +159,12 @@ nextblock: if step == 0 { continue } + // step == minInt64 cannot be safely negated below, because -step + // overflows back to minInt64. The later underflow checks need a + // positive magnitude, so reject this case here. + if step == minSignedValue(ind.Type) { + continue + } // startBody is the edge that eventually returns to the loop header. var startBody Edge |