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| author | Jorropo <jorropo.pgm@gmail.com> | 2025-07-04 09:25:23 +0200 |
|---|---|---|
| committer | Gopher Robot <gobot@golang.org> | 2025-07-24 13:49:03 -0700 |
| commit | d574856482859d259a95826dea404e648cbb8fef (patch) | |
| tree | 28d24d102c305ac460c254554e653fa2a46436a3 /src | |
| parent | 1a72920f0907259ca9c8fa73679242ca9774e353 (diff) | |
| download | go-d574856482859d259a95826dea404e648cbb8fef.tar.xz | |
cmd/compile: learn transitive proofs for safe negative signed adds
I've split this into it's own CL to make git bisect more effective.
Change-Id: Ib2c6dbc82fb04f50f2d17fbe6626c9fc322fb478
Reviewed-on: https://go-review.googlesource.com/c/go/+/685820
Auto-Submit: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/cmd/compile/internal/ssa/prove.go | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/prove.go b/src/cmd/compile/internal/ssa/prove.go index da42a675bf..cf045629cb 100644 --- a/src/cmd/compile/internal/ssa/prove.go +++ b/src/cmd/compile/internal/ssa/prove.go @@ -2212,6 +2212,20 @@ func addLocalFacts(ft *factsTable, b *Block) { } ft.update(b, v, v.Args[0], signed, r) } + if x.max <= 0 && !signedAddOverflowsOrUnderflows(x.min, y.min, v.Type) { + r := lt + if !x.nonzero() { + r |= eq + } + ft.update(b, v, v.Args[1], signed, r) + } + if y.max <= 0 && !signedAddOverflowsOrUnderflows(x.min, y.min, v.Type) { + r := lt + if !y.nonzero() { + r |= eq + } + ft.update(b, v, v.Args[0], signed, r) + } case OpAnd64, OpAnd32, OpAnd16, OpAnd8: ft.update(b, v, v.Args[0], unsigned, lt|eq) ft.update(b, v, v.Args[1], unsigned, lt|eq) |