On Thu, 12 Jul 2018, Jakub Jelinek wrote:
> Hi!
>
> The following testcase is a similar issue to PR84503 and the fix is similar,
> because coalesce_immediate_stores temporarily sorts the stores on ascending
> bitpos and if stores are merged, the merged store is emitted in the location
> of the latest of the stores, we need to verify that there is no overlap with
> other stores that are originally before that latest store from those we are
> considering and overlaps the set of stores we are considering to merge.
> In that case we need to punt and not merge (unless we do smarts like prove
> overlap between just some of the stores and force reordering).
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk and 8.2?
OK.
Thanks,
Richard.
> 2018-07-11 Jakub Jelinek
>
> PR tree-optimization/86492
> * gimple-ssa-store-merging.c
> (imm_store_chain_info::coalesce_immediate_stores): Call
> check_no_overlap even for the merge_overlapping case. Formatting fix.
>
> * gcc.c-torture/execute/pr86492.c: New test.
>
> --- gcc/gimple-ssa-store-merging.c.jj 2018-06-13 10:05:53.0 +0200
> +++ gcc/gimple-ssa-store-merging.c2018-07-11 19:24:12.084120206 +0200
> @@ -2702,7 +2702,12 @@ imm_store_chain_info::coalesce_immediate
> {
> /* Only allow overlapping stores of constants. */
> if (info->rhs_code == INTEGER_CST
> - && merged_store->stores[0]->rhs_code == INTEGER_CST)
> + && merged_store->stores[0]->rhs_code == INTEGER_CST
> + && check_no_overlap (m_store_info, i, INTEGER_CST,
> +MAX (merged_store->last_order, info->order),
> +MAX (merged_store->start
> + + merged_store->width,
> + info->bitpos + info->bitsize)))
> {
> merged_store->merge_overlapping (info);
> goto done;
> @@ -2732,10 +2737,8 @@ imm_store_chain_info::coalesce_immediate
> info->ops_swapped_p = true;
> }
> if (check_no_overlap (m_store_info, i, info->rhs_code,
> - MAX (merged_store->last_order,
> - info->order),
> - MAX (merged_store->start
> - + merged_store->width,
> + MAX (merged_store->last_order, info->order),
> + MAX (merged_store->start + merged_store->width,
>info->bitpos + info->bitsize)))
> {
> /* Turn MEM_REF into BIT_INSERT_EXPR for bit-field stores. */
> --- gcc/testsuite/gcc.c-torture/execute/pr86492.c.jj 2018-07-11
> 19:40:27.760122514 +0200
> +++ gcc/testsuite/gcc.c-torture/execute/pr86492.c 2018-07-11
> 19:40:13.460107841 +0200
> @@ -0,0 +1,34 @@
> +/* PR tree-optimization/86492 */
> +
> +union U
> +{
> + unsigned int r;
> + struct S
> + {
> +unsigned int a:12;
> +unsigned int b:4;
> +unsigned int c:16;
> + } f;
> +};
> +
> +__attribute__((noipa)) unsigned int
> +foo (unsigned int x)
> +{
> + union U u;
> + u.r = 0;
> + u.f.c = x;
> + u.f.b = 0xe;
> + return u.r;
> +}
> +
> +int
> +main ()
> +{
> + union U u;
> + if (__CHAR_BIT__ * __SIZEOF_INT__ != 32 || sizeof (u.r) != sizeof (u.f))
> +return 0;
> + u.r = foo (0x72);
> + if (u.f.a != 0 || u.f.b != 0xe || u.f.c != 0x72)
> +__builtin_abort ();
> + return 0;
> +}
>
> Jakub
>
>
--
Richard Biener
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
