[llvm] [PlaceSafepoints] Report usage error instead of asserting on invalid gc.safepoint_poll (PR #205520)

[Arda Serdar Pektezol via llvm-commits]

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@@ -629,11 +629,14 @@ InsertSafepointPoll(BasicBlock::iterator InsertBefore,
   // path call - where we need to insert a safepoint (parsepoint).
 
   auto *F = M->getFunction(GCSafepointPollName);
-  assert(F && "gc.safepoint_poll function is missing");
-  assert(F->getFunctionType() ==
-             FunctionType::get(Type::getVoidTy(M->getContext()), false) &&
-         "gc.safepoint_poll declared with wrong type");
-  assert(!F->empty() && "gc.safepoint_poll must be a non-empty function");
+  if (!F) {
+    reportFatalUsageError("gc.safepoint_poll function is missing");
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pektezol wrote:

I think other asserts besides this should stay. On non-assert opt, we crash due to nullderef on `F`. Can you add test cases for the other cases (`F->getFunctionType()`... and `F->empty()`) and see if it crashes on non-assert build with the asserts or not?

https://github.com/llvm/llvm-project/pull/205520