Roger Sayle - Re: [patch, 4.1.2, 4.2.1, 4.3] Fix a bug in pointer dependency test (original) (raw)

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• From: Roger Sayle
• To: Ira Rosen
• Cc: Diego Novillo ,
• Date: Sun, 18 Feb 2007 13:46:06 -0700 (MST)
• Subject: Re: [patch, 4.1.2, 4.2.1, 4.3] Fix a bug in pointer dependency test

Hi Ira (and Diego),

Re: http://gcc.gnu.org/ml/gcc-patches/2007-01/msg01228.html Re: http://gcc.gnu.org/ml/gcc-patches/2007-02/msg00230.html

On Fri, 2 Feb 2007, Diego Novillo wrote:

Ira Rosen wrote on 01/15/07 05:49:

 * tree-ssa-alias.c (may_aliases_intersect): New function.
 * tree-data-ref.c (ptr_ptr_may_alias_p): Call

may_aliases_intersect for different tags. * tree-flow.h (may_aliases_intersect): Add function declaration.

In mainline you no longer need this after Dan's bitmap conversion for alias sets.

The rest is OK everywhere.

It looks like this patch is responsible for today's regression of three gfortran test cases in the dejagnu testsuite on the 4.1 branch, namely gfortran.dg/vect/vect-2.c on x86_64-unknown-linux-gnu.

Instead of:

! vect-2.f90:7: note: LOOP VECTORIZED. ! vect-2.f90:7: note: vectorized 3 loops in function.

we now get

vect-2.f90:7: note: LOOP VECTORIZED. ! vect-2.f90:7: note: not vectorized: can't determine dependence between (*a_27)[D.955_25] and (*c_23)[D.955_25] ! vect-2.f90:7: note: vectorized 2 loops in function.

Interestingly, this test case is unchanged on mainline, where it currently passes. I'm wondering are there other alias related patches that need to be backported together with this fix?

Roger

• Follow-Ups:
  • Re: [patch, 4.1.2, 4.2.1, 4.3] Fix a bug in pointer dependency test
    * From: Ira Rosen
• References:
  • Re: [patch, 4.1.2, 4.2.1, 4.3] Fix a bug in pointer dependency test
    * From: Diego Novillo