[Bug middle-end/47046] gcc.target/i386/sse4_1-movntdqa.c ICEs with -fgraphite-identity

["spop at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47046

--- Comment #3 from Sebastian Pop <spop at gcc dot gnu.org> 2011-07-26 18:48:57 UTC ---
Author: spop
Date: Tue Jul 26 18:48:49 2011
New Revision: 176805

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=176805
Log:
Fix PR47046: correct evolution_function_is_affine_p

"Bug 47046 - gcc.target/i386/sse4_1-movntdqa.c ICEs with -fgraphite-identity"

The problem here is that we are left with the following code to be
translated in the new representation following the transform that
Graphite has chosen:

        D.2709_14 = j_33 * i_32;
        D.2710_15 = D.2709_14 * i_32;
        D.2711_16 = D.2710_15 * sign_34;
        *D.2708_13 = D.2711_16;

In this particular case we have a nonlinear expression "i * i" for
which we have to generate code following the new graphite_iv variables.

The patch fixes the function that detects whether we are passing non
linear stuff to graphite: evolution_function_is_affine_p.  It seems
like for the moment evolution_function_is_affine_p is testing whether
an evolution function is affine only in the innermost loop, without
looking recursively at what happens in outer loops.

The chrec for this case is: {0, +, {0, +, {1, +, 2}_1}_1}_2 and we are
testing whether the evolution is affine only for the loop_2, which is
true as we have {0, +, blah}_2 with blah invariant in loop_2.

The patch adds the recursive call to evolution_function_is_affine_p.

Bootstrapped and tested on amd64-linux.

2011-07-26  Sebastian Pop  <sebastian.pop@amd.com>

    PR middle-end/47046
    * tree-chrec.h (evolution_function_is_affine_p): Recursively call
    evolution_function_is_affine_p on CHREC_RIGHT.

    * gcc.dg/graphite/id-pr47046.c: New.

Added:
    trunk/gcc/testsuite/gcc.dg/graphite/id-pr47046.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-chrec.h