[turbofan] fix bug in DeadCodeElimination

Bug: chromium:1076708
Change-Id: I88a5eae0e562e32f1915deff3c4150ec4be14c6c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2181266
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Auto-Submit: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67564}

src/compiler/dead-code-elimination.cc

@@ -317,7 +317,10 @@ Reduction DeadCodeElimination::ReduceDeoptimizeOrReturnOrTerminateOrTailCall(
          node->opcode() == IrOpcode::kTailCall);
   Reduction reduction = PropagateDeadControl(node);
   if (reduction.Changed()) return reduction;
-  if (FindDeadInput(node) != nullptr) {
+  // Terminate nodes are not part of actual control flow, so they should never
+  // be replaced with Throw.
+  if (node->opcode() != IrOpcode::kTerminate &&
+      FindDeadInput(node) != nullptr) {
     Node* effect = NodeProperties::GetEffectInput(node, 0);
     Node* control = NodeProperties::GetControlInput(node, 0);
     if (effect->opcode() != IrOpcode::kUnreachable) {