Fix the objc_storeStrong recognizer to stop before walking off the

end of a basic block if there's no store.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156520 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 38 insertions, 1 deletions

diff --git a/lib/Transforms/Scalar/ObjCARC.cpp b/lib/Transforms/Scalar/ObjCARC.cpp
index 5d6e1a7d9f..ce4a195d95 100644
--- a/lib/Transforms/Scalar/ObjCARC.cpp
+++ b/lib/Transforms/Scalar/ObjCARC.cpp
@@ -3902,12 +3902,15 @@ void ObjCARCContract::ContractRelease(Instruction *Release,
   if (Load->getParent() != BB) return;
 
   // Walk down to find the store and the release, which may be in either order.
-  BasicBlock::iterator I = Load;
+  BasicBlock::iterator I = Load, End = BB->end();
   ++I;
   AliasAnalysis::Location Loc = AA->getLocation(Load);
   StoreInst *Store = 0;
   bool SawRelease = false;
   for (; !Store || !SawRelease; ++I) {
+    if (I == End)
+      return;
+
     Instruction *Inst = I;
     if (Inst == Release) {
       SawRelease = true;
diff --git a/test/Transforms/ObjCARC/contract-storestrong.ll b/test/Transforms/ObjCARC/contract-storestrong.ll
index de84b41b8e..2922f816d5 100644
--- a/test/Transforms/ObjCARC/contract-storestrong.ll
+++ b/test/Transforms/ObjCARC/contract-storestrong.ll
@@ -132,4 +132,38 @@ entry:
   ret i1 %t
 }
 
+; Like test0, but there's no store, so don't form an objc_storeStrong.
+
+;      CHECK: define void @test7(
+; CHECK-NEXT: entry:
+; CHECK-NEXT:   %0 = tail call i8* @objc_retain(i8* %p) nounwind
+; CHECK-NEXT:   %tmp = load i8** @x, align 8
+; CHECK-NEXT:   tail call void @objc_release(i8* %tmp) nounwind
+; CHECK-NEXT:   ret void
+; CHECK-NEXT: }
+define void @test7(i8* %p) {
+entry:
+  %0 = tail call i8* @objc_retain(i8* %p) nounwind
+  %tmp = load i8** @x, align 8
+  tail call void @objc_release(i8* %tmp) nounwind
+  ret void
+}
+
+; Like test0, but there's no retain, so don't form an objc_storeStrong.
+
+;      CHECK: define void @test8(
+; CHECK-NEXT: entry:
+; CHECK-NEXT:   %tmp = load i8** @x, align 8
+; CHECK-NEXT:   store i8* %p, i8** @x, align 8
+; CHECK-NEXT:   tail call void @objc_release(i8* %tmp) nounwind
+; CHECK-NEXT:   ret void
+; CHECK-NEXT: }
+define void @test8(i8* %p) {
+entry:
+  %tmp = load i8** @x, align 8
+  store i8* %p, i8** @x, align 8
+  tail call void @objc_release(i8* %tmp) nounwind
+  ret void
+}
+
 !0 = metadata !{}