diff options
Diffstat (limited to 'src/cmd/compile/internal/ssa/prove.go')
| -rw-r--r-- | src/cmd/compile/internal/ssa/prove.go | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/src/cmd/compile/internal/ssa/prove.go b/src/cmd/compile/internal/ssa/prove.go index bddc1abe43..0f015e8677 100644 --- a/src/cmd/compile/internal/ssa/prove.go +++ b/src/cmd/compile/internal/ssa/prove.go @@ -549,15 +549,29 @@ func (ft *factsTable) isNonNegative(v *Value) bool { return true } + var max int64 + switch v.Type.Size() { + case 1: + max = math.MaxInt8 + case 2: + max = math.MaxInt16 + case 4: + max = math.MaxInt32 + case 8: + max = math.MaxInt64 + default: + panic("unexpected integer size") + } + // Check if the recorded limits can prove that the value is positive - if l, has := ft.limits[v.ID]; has && (l.min >= 0 || l.umax <= math.MaxInt64) { + if l, has := ft.limits[v.ID]; has && (l.min >= 0 || l.umax <= uint64(max)) { return true } // Check if v = x+delta, and we can use x's limits to prove that it's positive if x, delta := isConstDelta(v); x != nil { if l, has := ft.limits[x.ID]; has { - if delta > 0 && l.min >= -delta && l.max <= math.MaxInt64-delta { + if delta > 0 && l.min >= -delta && l.max <= max-delta { return true } if delta < 0 && l.min >= -delta { |