[LVI] Handle conditions in the form of (cond1 && cond2)
Teach LVI how to gather information from conditions in the form of (cond1 && cond2). Our out-of-tree front-end emits range checks in this form.
Reviewed By: sanjoy
Differential Revision: http://reviews.llvm.org/D23200
llvm-svn: 278231
diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index f41978f..5faa975 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -1167,14 +1167,8 @@
return true;
}
-LVILatticeVal getValueFromCondition(Value *Val, Value *Cond, bool isTrueDest) {
- assert(Cond && "precondition");
-
- // For now we only support ICmpInst conditions
- ICmpInst *ICI = dyn_cast<ICmpInst>(Cond);
- if (!ICI)
- return LVILatticeVal::getOverdefined();
-
+static LVILatticeVal getValueFromICmpCondition(Value *Val, ICmpInst *ICI,
+ bool isTrueDest) {
Value *LHS = ICI->getOperand(0);
Value *RHS = ICI->getOperand(1);
CmpInst::Predicate Predicate = ICI->getPredicate();
@@ -1233,6 +1227,46 @@
return LVILatticeVal::getOverdefined();
}
+static LVILatticeVal
+getValueFromCondition(Value *Val, Value *Cond, bool isTrueDest,
+ DenseMap<Value*, LVILatticeVal> &Visited);
+
+static LVILatticeVal
+getValueFromConditionImpl(Value *Val, Value *Cond, bool isTrueDest,
+ DenseMap<Value*, LVILatticeVal> &Visited) {
+ if (ICmpInst *ICI = dyn_cast<ICmpInst>(Cond))
+ return getValueFromICmpCondition(Val, ICI, isTrueDest);
+
+ // Handle conditions in the form of (cond1 && cond2), we know that on the
+ // true dest path both of the conditions hold.
+ if (!isTrueDest)
+ return LVILatticeVal::getOverdefined();
+
+ BinaryOperator *BO = dyn_cast<BinaryOperator>(Cond);
+ if (!BO || BO->getOpcode() != BinaryOperator::And)
+ return LVILatticeVal::getOverdefined();
+
+ auto RHS = getValueFromCondition(Val, BO->getOperand(0), isTrueDest, Visited);
+ auto LHS = getValueFromCondition(Val, BO->getOperand(1), isTrueDest, Visited);
+ return intersect(RHS, LHS);
+}
+
+static LVILatticeVal
+getValueFromCondition(Value *Val, Value *Cond, bool isTrueDest,
+ DenseMap<Value*, LVILatticeVal> &Visited) {
+ auto I = Visited.find(Cond);
+ if (I != Visited.end())
+ return I->second;
+ return Visited[Cond] = getValueFromConditionImpl(Val, Cond, isTrueDest,
+ Visited);
+}
+
+LVILatticeVal getValueFromCondition(Value *Val, Value *Cond, bool isTrueDest) {
+ assert(Cond && "precondition");
+ DenseMap<Value*, LVILatticeVal> Visited;
+ return getValueFromCondition(Val, Cond, isTrueDest, Visited);
+}
+
/// \brief Compute the value of Val on the edge BBFrom -> BBTo. Returns false if
/// Val is not constrained on the edge. Result is unspecified if return value
/// is false.