In ARC, if we're emitting assembly markers for calls to

objc_retainAutoreleasedReturnValue, we need to also be killing
them during return peepholing.  Make sure we recognize an
intervening bitcast, but more importantly, assert if we can't
find the asm marker at all.  rdar://problem/12133032

llvm-svn: 163431

1 files changed, 17 insertions, 6 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 7d2b9d355ec..95bee4bd5a4 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -1363,12 +1363,23 @@ static llvm::Value *tryEmitFusedAutoreleaseOfResult(CodeGenFunction &CGF,
                                           .objc_retainAutoreleasedReturnValue) {
     doRetainAutorelease = false;
 
-    // Look for an inline asm immediately preceding the call and kill it, too.
-    llvm::Instruction *prev = call->getPrevNode();
-    if (llvm::CallInst *asmCall = dyn_cast_or_null<llvm::CallInst>(prev))
-      if (asmCall->getCalledValue()
-            == CGF.CGM.getARCEntrypoints().retainAutoreleasedReturnValueMarker)
-        insnsToKill.push_back(prev);
+    // If we emitted an assembly marker for this call (and the
+    // ARCEntrypoints field should have been set if so), go looking
+    // for that call.  If we can't find it, we can't do this
+    // optimization.  But it should always be the immediately previous
+    // instruction, unless we needed bitcasts around the call.
+    if (CGF.CGM.getARCEntrypoints().retainAutoreleasedReturnValueMarker) {
+      llvm::Instruction *prev = call->getPrevNode();
+      assert(prev);
+      if (isa<llvm::BitCastInst>(prev)) {
+        prev = prev->getPrevNode();
+        assert(prev);
+      }
+      assert(isa<llvm::CallInst>(prev));
+      assert(cast<llvm::CallInst>(prev)->getCalledValue() ==
+               CGF.CGM.getARCEntrypoints().retainAutoreleasedReturnValueMarker);
+      insnsToKill.push_back(prev);
+    }
   } else {
     return 0;
   }