Fix PR47046: correct evolution_function_is_affine_p

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.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@176805 138bc75d-0d04-0410-961f-82ee72b054a4