[PATCH] Fix PR48493

[Richard Guenther]

This fixes PR48493 by backporting a one-liner - we should not go
the movmisalign path for destinations that are not memory.

Bootstrapped and tested on x86_64-unknown-linux-gnu and on
mips by Andrew, installed.

Richard.

2012-05-31  Richard Guenther  <rguent...@suse.de>

        PR middle-end/48493
        * expr.c (expand_assignment): Do not use movmisalign on
        non-memory.

        * gcc.dg/torture/pr48493.c: New testcase.

Index: gcc/expr.c
===================================================================
*** gcc/expr.c  (revision 188009)
--- gcc/expr.c  (working copy)
*************** expand_assignment (tree to, tree from, b
*** 4593,4598 ****
--- 4593,4599 ----
    if ((TREE_CODE (to) == MEM_REF
         || TREE_CODE (to) == TARGET_MEM_REF)
        && mode != BLKmode
+       && !mem_ref_refers_to_non_mem_p (to)
        && ((align = get_object_or_type_alignment (to))
          < GET_MODE_ALIGNMENT (mode))
        && ((icode = optab_handler (movmisalign_optab, mode))
Index: gcc/testsuite/gcc.dg/torture/pr48493.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr48493.c      (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr48493.c      (revision 0)
***************
*** 0 ****
--- 1,18 ----
+ /* { dg-do compile } */
+ 
+ typedef long long T __attribute__((may_alias, aligned (1)));
+ 
+ struct S
+ {
+   _Complex float d __attribute__((aligned (8)));
+ };
+ 
+ void bar (struct S);
+ 
+ void
+ f1 (T x)
+ {
+   struct S s;
+   *(T *) ((char *) &s.d + 1) = x;
+   bar (s);
+ }