objc_retainBlock is not NoModRef because it can update forwarding pointers
in memory relevant to the optimizer. rdar://10050579.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139708 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/ObjCARC.cpp b/lib/Transforms/Scalar/ObjCARC.cpp
index d753cf1..f978f57 100644
--- a/lib/Transforms/Scalar/ObjCARC.cpp
+++ b/lib/Transforms/Scalar/ObjCARC.cpp
@@ -746,7 +746,6 @@
switch (GetBasicInstructionClass(CS.getInstruction())) {
case IC_Retain:
case IC_RetainRV:
- case IC_RetainBlock:
case IC_Autorelease:
case IC_AutoreleaseRV:
case IC_NoopCast:
@@ -754,6 +753,8 @@
case IC_FusedRetainAutorelease:
case IC_FusedRetainAutoreleaseRV:
// These functions don't access any memory visible to the compiler.
+ // Note that this doesn't include objc_retainBlock, becuase it updates
+ // pointers when it copies block data.
return NoModRef;
default:
break;