return false;
}
+bool ScalarEvolution::isKnownPredicateViaNoOverflow(ICmpInst::Predicate Pred,
+ const SCEV *LHS,
+ const SCEV *RHS) {
+
+ // Match Result to (X + Y)<ExpectedFlags> where Y is a constant integer.
+ // Return Y via OutY.
+ auto MatchBinaryAddToConst =
+ [this](const SCEV *Result, const SCEV *X, APInt &OutY,
+ SCEV::NoWrapFlags ExpectedFlags) {
+ const SCEV *NonConstOp, *ConstOp;
+ SCEV::NoWrapFlags FlagsPresent;
+
+ if (!splitBinaryAdd(Result, ConstOp, NonConstOp, FlagsPresent) ||
+ !isa<SCEVConstant>(ConstOp) || NonConstOp != X)
+ return false;
+
+ OutY = cast<SCEVConstant>(ConstOp)->getValue()->getValue();
+ return (FlagsPresent & ExpectedFlags) != 0;
+ };
+
+ APInt C;
+
+ switch (Pred) {
+ default:
+ break;
+
+ case ICmpInst::ICMP_SGE:
+ std::swap(LHS, RHS);
+ case ICmpInst::ICMP_SLE:
+ // X s<= (X + C)<nsw> if C >= 0
+ if (MatchBinaryAddToConst(RHS, LHS, C, SCEV::FlagNSW) && C.isNonNegative())
+ return true;
+
+ // (X + C)<nsw> s<= X if C <= 0
+ if (MatchBinaryAddToConst(LHS, RHS, C, SCEV::FlagNSW) &&
+ !C.isStrictlyPositive())
+ return true;
+
+ case ICmpInst::ICMP_SGT:
+ std::swap(LHS, RHS);
+ case ICmpInst::ICMP_SLT:
+ // X s< (X + C)<nsw> if C > 0
+ if (MatchBinaryAddToConst(RHS, LHS, C, SCEV::FlagNSW) &&
+ C.isStrictlyPositive())
+ return true;
+
+ // (X + C)<nsw> s< X if C < 0
+ if (MatchBinaryAddToConst(LHS, RHS, C, SCEV::FlagNSW) && C.isNegative())
+ return true;
+ }
+
+ return false;
+}
+
bool ScalarEvolution::isKnownPredicateViaSplitting(ICmpInst::Predicate Pred,
const SCEV *LHS,
const SCEV *RHS) {
auto IsKnownPredicateFull =
[this](ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS) {
return isKnownPredicateWithRanges(Pred, LHS, RHS) ||
- IsKnownPredicateViaMinOrMax(*this, Pred, LHS, RHS) ||
- IsKnownPredicateViaAddRecStart(*this, Pred, LHS, RHS);
+ IsKnownPredicateViaMinOrMax(*this, Pred, LHS, RHS) ||
+ IsKnownPredicateViaAddRecStart(*this, Pred, LHS, RHS) ||
+ isKnownPredicateViaNoOverflow(Pred, LHS, RHS);
};
switch (Pred) {