In the below, the test case tries to write to the stack outside the bounds of
the s variable? I can't imagine any good coming from this, and indeed, would
be nice for the compiler to complain about such code. If S had a few more
bytes at the end, at least the code would not be wildly bad.
Thoughts?
On May 31, 2012, at 3:59 AM, Richard Guenther <rguent...@suse.de> wrote:
> 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/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);
> + }
