// Keep constructing SCEVs' for phis recursively for now.
return nullptr;
- case Instruction::Select:
+ case Instruction::Select: {
+ // Check if U is a select that can be simplified to a SCEVUnknown.
+ auto CanSimplifyToUnknown = [this, U]() {
+ if (U->getType()->isIntegerTy(1) || isa<ConstantInt>(U->getOperand(0)))
+ return false;
+
+ auto *ICI = dyn_cast<ICmpInst>(U->getOperand(0));
+ if (!ICI)
+ return false;
+ Value *LHS = ICI->getOperand(0);
+ Value *RHS = ICI->getOperand(1);
+ if (ICI->getPredicate() == CmpInst::ICMP_EQ ||
+ ICI->getPredicate() == CmpInst::ICMP_NE) {
+ if (!(isa<ConstantInt>(RHS) && cast<ConstantInt>(RHS)->isZero()))
+ return true;
+ } else if (getTypeSizeInBits(LHS->getType()) >
+ getTypeSizeInBits(U->getType()))
+ return true;
+ return false;
+ };
+ if (CanSimplifyToUnknown())
+ return getUnknown(U);
+
for (Value *Inc : U->operands())
Ops.push_back(Inc);
return nullptr;
break;
-
+ }
case Instruction::Call:
case Instruction::Invoke:
if (Value *RV = cast<CallBase>(U)->getReturnedArgOperand()) {