[ObjCARC] Pass the correct BasicBlock to fix assertion failure.

The BasicBlock passed to FindPredecessorRetainWithSafePath should be the
parent block of Autorelease. This fixes a crash that occurs in
FindDependencies when StartInst is not in StartBB.

rdar://problem/33866381

llvm-svn: 312266

2 files changed, 21 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index 8f3a33f66c7..8c0a90843ef 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -2027,7 +2027,8 @@ void ObjCARCOpt::OptimizeReturns(Function &F) {
       continue;
 
     CallInst *Retain = FindPredecessorRetainWithSafePath(
-        Arg, &BB, Autorelease, DependingInstructions, Visited, PA);
+        Arg, Autorelease->getParent(), Autorelease, DependingInstructions,
+        Visited, PA);
     DependingInstructions.clear();
     Visited.clear();
 
diff --git a/llvm/test/Transforms/ObjCARC/rv.ll b/llvm/test/Transforms/ObjCARC/rv.ll
index e99ba92dc45..d84a875684f 100644
--- a/llvm/test/Transforms/ObjCARC/rv.ll
+++ b/llvm/test/Transforms/ObjCARC/rv.ll
@@ -314,6 +314,25 @@ define void @test25() {
   ret void
 }
 
+; Check that ObjCARCOpt::OptimizeReturns removes the redundant calls even when
+; they are not in the same basic block. This code used to cause an assertion
+; failure.
+
+; CHECK-LABEL: define i8* @test26()
+; CHECK: call i8* @returner()
+; CHECK-NOT:  call
+define i8* @test26() {
+bb0:
+  %v0 = call i8* @returner()
+  %v1 = tail call i8* @objc_retain(i8* %v0)
+  br label %bb1
+bb1:
+  %v2 = tail call i8* @objc_autoreleaseReturnValue(i8* %v1)
+  br label %bb2
+bb2:
+  ret i8* %v2
+}
+
 !0 = !{}
 
 ; CHECK: attributes [[NUW]] = { nounwind }