Fix assert in ObjCARC optimizer when deleting retainBlock of null or undef.

The caller to EraseInstruction had this conditional:

    // ARC calls with null are no-ops. Delete them.
    if (IsNullOrUndef(Arg))

but the assert inside EraseInstruction only allowed ConstantPointerNull and not
undef or bitcasts.

This adds support for both of these cases.

rdar://problem/47003805

llvm-svn: 350261

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARC.h b/llvm/lib/Transforms/ObjCARC/ObjCARC.h
index 1dbe72c7569..751c8f30e81 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARC.h
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARC.h
@@ -58,7 +58,7 @@ static inline void EraseInstruction(Instruction *CI) {
     // Replace the return value with the argument.
     assert((IsForwarding(GetBasicARCInstKind(CI)) ||
             (IsNoopOnNull(GetBasicARCInstKind(CI)) &&
-             isa<ConstantPointerNull>(OldArg))) &&
+             IsNullOrUndef(OldArg->stripPointerCasts()))) &&
            "Can't delete non-forwarding instruction with users!");
     CI->replaceAllUsesWith(OldArg);
   }