[Attributor] Fold terminators before changing instructions to unreachable
It is possible that an instruction to be changed to unreachable is
in the same block with a terminator that can be constant-folded.
In this case, as of now, the instruction will be changed to
unreachable before the terminator is folded. But, then the
whole BB becomes invalidated and so when we go ahead to fold
the terminator, we trap.
Change the order of these two.
Differential Revision: https://reviews.llvm.org/D75780
diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index f08d7f8..3aef6e9 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -7798,15 +7798,15 @@
ToBeChangedToUnreachableInsts.insert(&NormalDestBB->front());
}
}
+ for (Instruction *I : TerminatorsToFold) {
+ CGModifiedFunctions.insert(I->getFunction());
+ ConstantFoldTerminator(I->getParent());
+ }
for (auto &V : ToBeChangedToUnreachableInsts)
if (Instruction *I = dyn_cast_or_null<Instruction>(V)) {
CGModifiedFunctions.insert(I->getFunction());
changeToUnreachable(I, /* UseLLVMTrap */ false);
}
- for (Instruction *I : TerminatorsToFold) {
- CGModifiedFunctions.insert(I->getFunction());
- ConstantFoldTerminator(I->getParent());
- }
for (auto &V : ToBeDeletedInsts) {
if (Instruction *I = dyn_cast_or_null<Instruction>(V)) {