===================================================================
@@ -10270,10 +10270,15 @@ expand_expr_real_1 (tree exp, rtx target
{
enum insn_code icode;
- op0 = copy_rtx (op0);
-
if (TYPE_ALIGN_OK (type))
- set_mem_align (op0, MAX (MEM_ALIGN (op0), TYPE_ALIGN (type)));
+ {
+ /* ??? Copying the MEM without substantially changing it might
+ run afoul of the code handling volatile memory references in
+ store_expr, which assumes that TARGET is returned unmodified
+ if it has been used. */
+ op0 = copy_rtx (op0);
+ set_mem_align (op0, MAX (MEM_ALIGN (op0), TYPE_ALIGN (type)));
+ }
else if (mode != BLKmode
&& MEM_ALIGN (op0) < GET_MODE_ALIGNMENT (mode)
/* If the target does have special handling for unaligned