[AggressiveInstCombine] Fixed TruncCombine class to handle TruncInst leaf node correctly.
This covers the case where TruncInst leaf node is a constant expression.
See PR36121 for more details.
Differential Revision: https://reviews.llvm.org/D42622
llvm-svn: 323926
diff --git a/llvm/lib/Transforms/AggressiveInstCombine/TruncInstCombine.cpp b/llvm/lib/Transforms/AggressiveInstCombine/TruncInstCombine.cpp
index 0378ea7..d62b643 100644
--- a/llvm/lib/Transforms/AggressiveInstCombine/TruncInstCombine.cpp
+++ b/llvm/lib/Transforms/AggressiveInstCombine/TruncInstCombine.cpp
@@ -317,6 +317,7 @@
// just return the source. There's no need to insert it because it is not
// new.
if (I->getOperand(0)->getType() == Ty) {
+ assert(!isa<TruncInst>(I) && "Cannot reach here with TruncInst");
NodeInfo.NewValue = I->getOperand(0);
continue;
}
@@ -326,11 +327,18 @@
Opc == Instruction::SExt);
// Update Worklist entries with new value if needed.
- if (auto *NewCI = dyn_cast<TruncInst>(Res)) {
- auto Entry = find(Worklist, I);
- if (Entry != Worklist.end())
+ // There are three possible changes to the Worklist:
+ // 1. Update Old-TruncInst -> New-TruncInst.
+ // 2. Remove Old-TruncInst (if New node is not TruncInst).
+ // 3. Add New-TruncInst (if Old node was not TruncInst).
+ auto Entry = find(Worklist, I);
+ if (Entry != Worklist.end()) {
+ if (auto *NewCI = dyn_cast<TruncInst>(Res))
*Entry = NewCI;
- }
+ else
+ Worklist.erase(Entry);
+ } else if (auto *NewCI = dyn_cast<TruncInst>(Res))
+ Worklist.push_back(NewCI);
break;
}
case Instruction::Add: