[Bug c/35634] [4.1/4.2/4.3/4.4 Regression] operand of pre-/postin-/decrement not promoted

["rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #13 from rguenther at suse dot de  2008-04-09 15:26 -------
Subject: Re:  [4.1/4.2/4.3/4.4 Regression] operand of
 pre-/postin-/decrement not promoted

On Wed, 9 Apr 2008, jakub at gcc dot gnu dot org wrote:

> ------- Comment #12 from jakub at gcc dot gnu dot org  2008-04-09 14:32 -------
> Created an attachment (id=15455)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15455&action=view)
>  --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=15455&action=view)
> gcc43-pr35634.patch
> 
> Here is the updated FE only patch.  One change is that it avoids
> P{RE,OST}{IN,DE}CREMENT_EXPR only for the promoting types, and has some
> (admittedly very ugly) OpenMP parsing changes to counter that.  Unfortunately
> unlike #pragma omp for increment, #pragma omp atomic can have some_lvalue++
> , not necessarily a variable_name++, so I have no idea how to handle that.
> 
> On x86_64 with this patch I get 3 omp failures (2 in libgomp atomic-10.c, one
> in gcc/testsuite atomic-1.c) and:
> FAIL: gcc.dg/vect/pr18536.c scan-tree-dump-times vect "vectorized 1 loops" 1
> FAIL: gcc.dg/vect/pr30771.c scan-tree-dump-times vect "vectorized 1 loops" 1
> FAIL: gcc.dg/vect/vect-iv-8a.c scan-tree-dump-times vect "vectorized 1 loops" 1
> FAIL: gcc.dg/vect/vect-multitypes-11.c scan-tree-dump-times vect "vectorized 1
> loops" 2
> so (depending on where the other patch was tested) doing this in the FE doesn't
> help much or at all.

Thanks!

I will try doing the P{RE,OST}{IN,DE}CREMENT_EXPR semantic change and
handling it in the gimplifier.  Just because I am curious how much
I break the frontends...

After the summit paper deadline is over ;)

Richard.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35634