+Constant *CorrelatedValuePropagation::getConstantAt(Value *V, Instruction *At) {
+ if (Constant *C = LVI->getConstant(V, At->getParent(), At))
+ return C;
+
+ // TODO: The following really should be sunk inside LVI's core algorithm, or
+ // at least the outer shims around such.
+ auto *C = dyn_cast<CmpInst>(V);
+ if (!C) return nullptr;
+
+ Value *Op0 = C->getOperand(0);
+ Constant *Op1 = dyn_cast<Constant>(C->getOperand(1));
+ if (!Op1) return nullptr;
+
+ LazyValueInfo::Tristate Result =
+ LVI->getPredicateAt(C->getPredicate(), Op0, Op1, At);
+ if (Result == LazyValueInfo::Unknown)
+ return nullptr;
+
+ return (Result == LazyValueInfo::True) ?
+ ConstantInt::getTrue(C->getContext()) :
+ ConstantInt::getFalse(C->getContext());
+}
+