(note_mem_written): QImode varying structure memory accesses can alias scalars.

From-SVN: r3654

diff --git a/gcc/cse.c b/gcc/cse.c
index 4249af6..855242d 100644 (file)
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -6885,9 +6885,12 @@ note_mem_written (written, writes_ptr)
        {
          /* A varying address that is a sum indicates an array element,
             and that's just as good as a structure element
-            in implying that we need not invalidate scalar variables.  */
-         if (!(MEM_IN_STRUCT_P (written)
-               || GET_CODE (XEXP (written, 0)) == PLUS))
+            in implying that we need not invalidate scalar variables.
+            However, we must allow QImode aliasing of scalars, because the
+            ANSI C standard allows character pointers to alias anything.  */
+         if (! ((MEM_IN_STRUCT_P (written)
+                 || GET_CODE (XEXP (written, 0)) == PLUS)
+                && GET_MODE (written) != QImode))
            writes_ptr->all = 1;
          writes_ptr->nonscalar = 1;
        }