On Wed, 11 Mar 2020, Jakub Jelinek wrote:
> Hi!
>
> As the testcase shows, arithmetics that for -ftrapv would need multiple
> basic blocks can show up not just in nb_bytes expressions where we
> are calling rewrite_to_non_trapping_overflow for a while already,
> but also in the pointer expression to the start of the region.
> While the testcase covers just the first hunk and I've failed to create
> a testcase for the latter, it is at least in theory possible too, so I've
> adjusted that hunk too.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Thanks,
Richard.
> 2020-03-11 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/94114
> * tree-loop-distribution.c (generate_memset_builtin): Call
> rewrite_to_non_trapping_overflow even on mem.
> (generate_memcpy_builtin): Call rewrite_to_non_trapping_overflow even
> on dest and src.
>
> * gcc.dg/pr94114.c: New test.
>
> --- gcc/tree-loop-distribution.c.jj 2020-01-12 11:54:38.497381967 +0100
> +++ gcc/tree-loop-distribution.c 2020-03-10 08:20:42.830265273 +0100
> @@ -1151,7 +1151,7 @@ generate_memset_builtin (class loop *loo
> nb_bytes = rewrite_to_non_trapping_overflow (builtin->size);
> nb_bytes = force_gimple_operand_gsi (&gsi, nb_bytes, true, NULL_TREE,
> false, GSI_CONTINUE_LINKING);
> - mem = builtin->dst_base;
> + mem = rewrite_to_non_trapping_overflow (builtin->dst_base);
> mem = force_gimple_operand_gsi (&gsi, mem, true, NULL_TREE,
> false, GSI_CONTINUE_LINKING);
>
> @@ -1205,8 +1205,8 @@ generate_memcpy_builtin (class loop *loo
> nb_bytes = rewrite_to_non_trapping_overflow (builtin->size);
> nb_bytes = force_gimple_operand_gsi (&gsi, nb_bytes, true, NULL_TREE,
> false, GSI_CONTINUE_LINKING);
> - dest = builtin->dst_base;
> - src = builtin->src_base;
> + dest = rewrite_to_non_trapping_overflow (builtin->dst_base);
> + src = rewrite_to_non_trapping_overflow (builtin->src_base);
> if (partition->kind == PKIND_MEMCPY
> || ! ptr_derefs_may_alias_p (dest, src))
> kind = BUILT_IN_MEMCPY;
> --- gcc/testsuite/gcc.dg/pr94114.c.jj 2020-03-10 08:21:07.369900379 +0100
> +++ gcc/testsuite/gcc.dg/pr94114.c 2020-03-10 08:19:06.691694811 +0100
> @@ -0,0 +1,13 @@
> +/* PR tree-optimization/94114 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -ftree-loop-distribute-patterns -ftrapv" } */
> +
> +void
> +foo (int *x, int *y, int *z, long int w)
> +{
> + while (y + w > z)
> + {
> + x[w] = 0;
> + --w;
> + }
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
