Re: [patch] Fix PR tree-optimization/49471

[Richard Guenther <richard dot guenther at gmail dot com>]

On Mon, Jul 25, 2011 at 4:47 PM, Razya Ladelsky <RAZYA@il.ibm.com> wrote:
> Hi,
>
> This patch fixes the build failure of cactusADM and dealII spec2006
> benchmarks when autopar is enabled.
> (for powerpc they fail only when -m32 is additionally enabled)
>
> The problem originated in canonicalize_loop_ivs, where we iterate the
> header's phis in order to base all
> the induction variables on a single control variable.
> We use the largest precision of the loop's ivs in order to determine the
> type of the control variable.
>
> Since iterating the loop's phis takes into account not only the loop's
> ivs, but also reduction variables,
> we got precision values like 80 for x86, or 128 for ppc.
> The compilers failed to create proper types for these sizes
> (respectively).
>
> The proper behavior for determining the control variable's type is to take
> into account only the loop's ivs,
> which is what this patch does.
>
> Bootstrap and testsuite pass successfully (as autopar is not enabled by
> default).
> No new regressions when the testsuite is run with autopar enabled.
> No new regressions for the run of spec2006 with autopar enabled,
>
> cactusADM and dealII benchmarks now pass successfully with autopar on
> powerpc and x86.
>
> Thanks to Zdenek who helped me figure out the failure/fix.
> OK for trunk?

It'll collide with Sebastians patch in that area.  I suggested a
INTEGRAL_TYPE_P check instead of the simple_iv one, it
should be cheaper.  Zdenek, do you think it will be "incorrect"
in some cases?

Thanks,
Richard.

> Thanks,
> Razya
>
> ChangeLog:
>
> ? PR tree-optimization/49471
> ? * tree-vect-loop-manip.c (canonicalize_loop_ivs): Add condition to
> ? ignore reduction variables when iterating the loop header's phis.
>
>
>