[GlobalOpt] Fix assertion failure during instruction deletion

This fixes the assertion failure reported in https://reviews.llvm.org/D114889#3166417,
by making RecursivelyDeleteTriviallyDeadInstructionsPermissive()
more permissive. As the function accepts a WeakTrackingVH, even if
originally only Instructions were inserted, we may end up with
different Value types after a RAUW operation. As such, we should
not assume that the vector only contains instructions.

Notably this matches the behavior of the
RecursivelyDeleteTriviallyDeadInstructions() function variant which
accepts a single value rather than vector.

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 99eed9e..ec926b1 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -529,8 +529,8 @@ bool llvm::RecursivelyDeleteTriviallyDeadInstructionsPermissive(
     std::function<void(Value *)> AboutToDeleteCallback) {
   unsigned S = 0, E = DeadInsts.size(), Alive = 0;
   for (; S != E; ++S) {
-    auto *I = cast<Instruction>(DeadInsts[S]);
-    if (!isInstructionTriviallyDead(I)) {
+    auto *I = dyn_cast<Instruction>(DeadInsts[S]);
+    if (!I || !isInstructionTriviallyDead(I)) {
       DeadInsts[S] = nullptr;
       ++Alive;
     }