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Re: [PATCH] Fix PR54211
- From: Richard Guenther <rguenther at suse dot de>
- To: "William J. Schmidt" <wschmidt at linux dot vnet dot ibm dot com>
- Cc: gcc-patches at gcc dot gnu dot org, bergner at vnet dot ibm dot com
- Date: Fri, 10 Aug 2012 10:51:59 +0200 (CEST)
- Subject: Re: [PATCH] Fix PR54211
- References: <1344561084.18792.11.camel@gnopaine>
On Thu, 9 Aug 2012, William J. Schmidt wrote:
> Fix a thinko in strength reduction. I was checking the type of the
> wrong operand to determine whether address arithmetic should be used in
> replacing expressions. This produced a spurious POINTER_PLUS_EXPR when
> an address was converted to an unsigned long and back again.
>
> Bootstrapped and tested on powerpc64-unknown-linux-gnu with no new
> regressions. Ok for trunk?
Ok.
Thanks,
Richard.
> Thanks,
> Bill
>
>
> gcc:
>
> 2012-08-09 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
>
> PR middle-end/54211
> * gimple-ssa-strength-reduction.c (analyze_candidates_and_replace):
> Use cand_type to determine whether pointer arithmetic will be generated.
>
> gcc/testsuite:
>
> 2012-08-09 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
>
> PR middle-end/54211
> * gcc.dg/tree-ssa/pr54211.c: New test.
>
>
> Index: gcc/testsuite/gcc.dg/tree-ssa/pr54211.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/tree-ssa/pr54211.c (revision 0)
> +++ gcc/testsuite/gcc.dg/tree-ssa/pr54211.c (revision 0)
> @@ -0,0 +1,28 @@
> +/* { dg-do compile } */
> +/* { dg-options "-Os" } */
> +
> +int a, b;
> +unsigned char e;
> +void fn1 ()
> +{
> + unsigned char *c=0;
> + for (;; a++)
> + {
> + unsigned char d = *(c + b);
> + for (; &e<&d; c++)
> + goto Found_Top;
> + }
> +Found_Top:
> + if (0)
> + goto Empty_Bitmap;
> + for (;; a++)
> + {
> + unsigned char *e = c + b;
> + for (; c < e; c++)
> + goto Found_Bottom;
> + c -= b;
> + }
> +Found_Bottom:
> +Empty_Bitmap:
> + ;
> +}
> Index: gcc/gimple-ssa-strength-reduction.c
> ===================================================================
> --- gcc/gimple-ssa-strength-reduction.c (revision 190260)
> +++ gcc/gimple-ssa-strength-reduction.c (working copy)
> @@ -2534,7 +2534,7 @@ analyze_candidates_and_replace (void)
> /* Determine whether we'll be generating pointer arithmetic
> when replacing candidates. */
> address_arithmetic_p = (c->kind == CAND_ADD
> - && POINTER_TYPE_P (TREE_TYPE (c->base_expr)));
> + && POINTER_TYPE_P (c->cand_type));
>
> /* If all candidates have already been replaced under other
> interpretations, nothing remains to be done. */
>
>
>
--
Richard Guenther <rguenther@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend