Add some simple insertvalue simplifications, for the purpose of cleaning
up do-nothing exception handling code produced by dragonegg.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139113 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index cfff9c0..deb7fed 100644
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -2270,6 +2270,35 @@
return ConstantExpr::getGetElementPtr(cast<Constant>(Ops[0]), Ops.slice(1));
}
+/// SimplifyInsertValueInst - Given operands for an InsertValueInst, see if we
+/// can fold the result. If not, this returns null.
+Value *llvm::SimplifyInsertValueInst(Value *Agg, Value *Val,
+ ArrayRef<unsigned> Idxs,
+ const TargetData *,
+ const DominatorTree *) {
+ if (Constant *CAgg = dyn_cast<Constant>(Agg))
+ if (Constant *CVal = dyn_cast<Constant>(Val))
+ return ConstantFoldInsertValueInstruction(CAgg, CVal, Idxs);
+
+ // insertvalue x, undef, n -> x
+ if (match(Val, m_Undef()))
+ return Agg;
+
+ // insertvalue x, (extractvalue y, n), n
+ if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Val))
+ if (EV->getIndices() == Idxs) {
+ // insertvalue undef, (extractvalue y, n), n -> y
+ if (match(Agg, m_Undef()))
+ return EV->getAggregateOperand();
+
+ // insertvalue y, (extractvalue y, n), n -> y
+ if (Agg == EV->getAggregateOperand())
+ return Agg;
+ }
+
+ return 0;
+}
+
/// SimplifyPHINode - See if we can fold the given phi. If not, returns null.
static Value *SimplifyPHINode(PHINode *PN, const DominatorTree *DT) {
// If all of the PHI's incoming values are the same then replace the PHI node
@@ -2471,6 +2500,13 @@
Result = SimplifyGEPInst(Ops, TD, DT);
break;
}
+ case Instruction::InsertValue: {
+ InsertValueInst *IV = cast<InsertValueInst>(I);
+ Result = SimplifyInsertValueInst(IV->getAggregateOperand(),
+ IV->getInsertedValueOperand(),
+ IV->getIndices(), TD, DT);
+ break;
+ }
case Instruction::PHI:
Result = SimplifyPHINode(cast<PHINode>(I), DT);
break;