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.

From-SVN: r176805

gcc/ChangeLog

 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.
+
+2011-07-26  Sebastian Pop  <sebastian.pop@amd.com>
+
 	* tree-data-ref.c (max_stmt_executions_tree): Do not call
 	lang_hooks.types.type_for_size.
 

gcc/testsuite/ChangeLog

 2011-07-26  Sebastian Pop  <sebastian.pop@amd.com>
 
+	PR middle-end/47046
+	* gcc.dg/graphite/id-pr47046.c: New.
+
+2011-07-26  Sebastian Pop  <sebastian.pop@amd.com>
+
 	PR middle-end/47653
 	* gcc.dg/graphite/run-id-pr47593.c: New.
 

gcc/testsuite/gcc.dg/graphite/id-pr47046.c

+void
+init_movntdqa (int *src)
+{
+  int i, j, sign = 1;
+
+  for (i = 0; i < 20; i++)
+    for (j = 0; j < 4; j++)
+      {
+	src[i * 4 + j] = j * i * i * sign;
+	sign = -sign;
+      }
+}
+

gcc/tree-chrec.h

@@ -205,7 +205,9 @@ evolution_function_is_affine_p (const_tree chrec)
   return chrec
     && TREE_CODE (chrec) == POLYNOMIAL_CHREC
     && evolution_function_is_invariant_p (CHREC_RIGHT (chrec),
-					  CHREC_VARIABLE (chrec));
+					  CHREC_VARIABLE (chrec))
+    && (TREE_CODE (CHREC_RIGHT (chrec)) != POLYNOMIAL_CHREC
+	|| evolution_function_is_affine_p (CHREC_RIGHT (chrec)));
 }
 
 /* Determines whether EXPR does not contains chrec expressions.  */