[Bug tree-optimization/41811] graphite miscompiles 454.calculix of the SPEC 2k6

["sebpop at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

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------- Comment #4 from sebpop at gmail dot com  2009-10-23 19:54 -------
Subject: Re:  graphite miscompiles 454.calculix 
        of the SPEC 2k6

On Fri, Oct 23, 2009 at 14:46, spop at gcc dot gnu dot org
<gcc-bugzilla@gcc.gnu.org> wrote:
> and the code generated by CLooG for the interchange looks like this:
>
> for (scat_1=0;scat_1<=2;scat_1++) {
>  for (scat_3=0;scat_3<=2;scat_3++) {
>    S4(scat_1,scat_3) ;
>    for (scat_5=0;scat_5<=2;scat_5++) {
>      S5(scat_1,scat_5,scat_3) ;
>    }
>    S7(scat_1,scat_3) ;
>    S18(scat_1,scat_3) ;
>  }

S7 and S18 should not be generated before S5 finishes to execute over
all the iterations of the original innermost loop (do k=1,20).

S7 and S18 contain the end of the reduction and the write in the array
xs(i,j) that is independent of the k loop.

>  for (scat_3=3;scat_3<=19;scat_3++) {
>    for (scat_5=0;scat_5<=2;scat_5++) {
>      S5(scat_1,scat_5,scat_3) ;
>    }
>  }
> }


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41811