diff --git a/lib/Analysis/LazyValueInfo.cpp b/lib/Analysis/LazyValueInfo.cpp index 7ec35cdcc5b..48778232002 100644 --- a/lib/Analysis/LazyValueInfo.cpp +++ b/lib/Analysis/LazyValueInfo.cpp @@ -91,6 +91,11 @@ public: Res.markNotConstant(C); return Res; } + static LVILatticeVal getRange(ConstantRange CR) { + LVILatticeVal Res; + Res.markConstantRange(CR); + return Res; + } bool isUndefined() const { return Tag == undefined; } bool isConstant() const { return Tag == constant; } @@ -507,13 +512,35 @@ LVILatticeVal LVIQuery::getEdgeValue(BasicBlock *BBFrom, BasicBlock *BBTo) { // If the condition of the branch is an equality comparison, we may be // able to infer the value. if (ICmpInst *ICI = dyn_cast(BI->getCondition())) - if (ICI->isEquality() && ICI->getOperand(0) == Val && - isa(ICI->getOperand(1))) { - // We know that V has the RHS constant if this is a true SETEQ or - // false SETNE. - if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ)) - return LVILatticeVal::get(cast(ICI->getOperand(1))); - return LVILatticeVal::getNot(cast(ICI->getOperand(1))); + if (ICI->getOperand(0) == Val && isa(ICI->getOperand(1))) { + if (ICI->isEquality()) { + // We know that V has the RHS constant if this is a true SETEQ or + // false SETNE. + if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ)) + return LVILatticeVal::get(cast(ICI->getOperand(1))); + return LVILatticeVal::getNot(cast(ICI->getOperand(1))); + } else if (ConstantInt *CI = + dyn_cast(ICI->getOperand(1))) { + + // Calculate the range of values that would satisfy the comparison. + ConstantRange CmpRange(CI->getValue(), CI->getValue()+1); + ConstantRange TrueValues = + ConstantRange::makeICmpRegion(ICI->getPredicate(), CmpRange); + + // If we're interested in the false dest, invert the condition. + if (!isTrueDest) TrueValues = TrueValues.inverse(); + + // Figure out the possible values of the query BEFORE this branch. + LVILatticeVal InBlock = getBlockValue(BBFrom); + if (!InBlock.isConstantRange()) return InBlock; + + // Find all potential values that satisfy both the input and output + // conditions. + ConstantRange PossibleValues = + TrueValues.intersectWith(InBlock.getConstantRange()); + + return LVILatticeVal::getRange(PossibleValues); + } } } } @@ -730,7 +757,7 @@ LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C, ConstantRange TrueValues = ConstantRange::makeICmpRegion(Pred, RHS); if (CR.intersectWith(TrueValues).isEmptySet()) return False; - else if (CR.intersectWith(TrueValues) == CR) + else if (TrueValues.contains(CR)) return True; return Unknown;