On Tue, 27 Mar 2012, Martin Jambor wrote:
> Hi,
>
> this fixes a thinko that leads to wrong-code generation that is in the
> "new" SRA since the beginning. When there are two unscalarizable
> regions in an access tree, one within another, the aggregate
> assignment modification code may use them as basis of new memory
> accesses, which means it very likely ignores an array reference along
> the way. Using such a region in the code path is useless anyway since
> by its nature there cannot be any replacements there.
>
> This is a patch for trunk (on which it has passed bootstrap and
> testing on x86_64-linux) and the 4.7 branch, I'm in the process of
> testing equivalents for the 4.5 and 4.6 branches (the diff contexts
> differ slightly). OK for everywhere if all tests pass?
Ok.
Thanks,
Richard.
> Thanks,
>
> Martin
>
>
> 2012-03-24 Martin Jambor <mjam...@suse.cz>
>
> PR middle-end/52693
> * tree-sra.c (sra_modify_assign): Do not call
> load_assign_lhs_subreplacements when working with an unscalarizable
> region.
>
> * testsuite/gcc.dg/torture/pr52693.c: New test.
>
>
> Index: src/gcc/tree-sra.c
> ===================================================================
> --- src.orig/gcc/tree-sra.c
> +++ src/gcc/tree-sra.c
> @@ -3071,7 +3071,13 @@ sra_modify_assign (gimple *stmt, gimple_
> }
> else
> {
> - if (access_has_children_p (lacc) && access_has_children_p (racc))
> + if (access_has_children_p (lacc)
> + && access_has_children_p (racc)
> + /* When an access represents an unscalarizable region, it usually
> + represents accesses with variable offset and thus must not be used
> + to generate new memory accesses. */
> + && !lacc->grp_unscalarizable_region
> + && !racc->grp_unscalarizable_region)
> {
> gimple_stmt_iterator orig_gsi = *gsi;
> enum unscalarized_data_handling refreshed;
> Index: src/gcc/testsuite/gcc.dg/torture/pr52693.c
> ===================================================================
> --- /dev/null
> +++ src/gcc/testsuite/gcc.dg/torture/pr52693.c
> @@ -0,0 +1,33 @@
> +/* { dg-do run } */
> +
> +struct pair
> +{
> + int x;
> + int y;
> +};
> +
> +struct array
> +{
> + struct pair elems[ 2 ];
> + unsigned index;
> +};
> +
> +extern void abort ();
> +
> +void __attribute__ ((noinline,noclone))
> +test_results (int x1, int y1, int x2, int y2)
> +{
> + if (x1 != x2 || y1 != y2)
> + abort ();
> +}
> +
> +int
> +main (void)
> +{
> + struct array arr = {{{1,2}, {3,4}}, 1};
> + struct pair last = arr.elems[arr.index];
> +
> + test_results ( last.x, last.y, arr.elems[1].x, arr.elems[1].y);
> +
> + return 0;
> +}
>
>
--
Richard Guenther <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer
