Revert r145273 and fix in SelectionDAG::InferPtrAlignment() instead.

Conservatively returns zero when the GV does not specify an alignment nor is it
initialized. Previously it returns ABI alignment for type of the GV. However, if
the type is a "packed" type, then the under-specified alignments is attached to
the load / store instructions. In that case, the alignment of the type cannot be
trusted.
rdar://10464621


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145300 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index a772a46ba6..024a163737 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -6564,7 +6564,11 @@ unsigned SelectionDAG::InferPtrAlignment(SDValue Ptr) const {
         }
       }
       if (!Align)
-        Align = TLI.getTargetData()->getABITypeAlignment(GV->getType());
+        // Conservatively returns zero here instead of using ABI alignment for
+        // type of the GV. If the type is a "packed" type, then the under-
+        // specified alignments is attached to the load / store instructions.
+        // In that case, the alignment of the type cannot be trusted.
+        return 0;
     }
     return MinAlign(Align, GVOffset);
   }