align varargs stack writes to the proper 4-byte boundaries

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/Transforms/NaCl/ExpandVarArgs.cpp b/lib/Transforms/NaCl/ExpandVarArgs.cpp
index 0fd1a3cb44..578ea4cc0e 100644
--- a/lib/Transforms/NaCl/ExpandVarArgs.cpp
+++ b/lib/Transforms/NaCl/ExpandVarArgs.cpp
@@ -257,7 +257,9 @@ static bool ExpandVarArgCall(InstType *Call, DataLayout *DL) {
           DL->getTypeAllocSize((*Iter)->getType()->getPointerElementType()),
           /* Align= */ 1);
     } else {
-      CopyDebug(new StoreInst(*Iter, Ptr, Call), Call);
+      StoreInst *S = new StoreInst(*Iter, Ptr, Call);
+      CopyDebug(S, Call);
+      S->setAlignment(4); // EMSCRIPTEN: pnacl stack is only 4-byte aligned
     }
   }