When "low alignment" is specified, then set the alignment of the aggregate's

store to 1. This allows code-gen to select a more appropriate alignment. If left
to zero, an alignment greater than the alignment of the pointer may be selected,
causing code-gen to use instructions which require an alignment greater than the
pointer guarantees.
<rdar://problem/11043589>


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@152951 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 4fe4fa8a14..4455f1a086 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -623,7 +623,9 @@ static void BuildAggStore(CodeGenFunction &CGF, llvm::Value *Val,
         SI->setAlignment(1);
     }
   } else {
-    CGF.Builder.CreateStore(Val, DestPtr, DestIsVolatile);
+    llvm::StoreInst *SI = CGF.Builder.CreateStore(Val, DestPtr, DestIsVolatile);
+    if (LowAlignment)
+      SI->setAlignment(1);
   }
 }