[PATCH] Fix number_of_iterations_cond (PR tree-optimization/53550)

[Jakub Jelinek]

Hi!

tree-chrec.c and tree-scalar-evolutions.c uses sizetype as type of
iv->step, but the following spot would use POINTER_TYPE, which leads
to ICEs.  Fixed thusly, bootstrapped/regtested onx 86_64-linux and
i686-linux, ok for trunk/4.7?

2012-06-02  Jakub Jelinek  <ja...@redhat.com>

        PR tree-optimization/53550
        * tree-ssa-loop-niter.c (number_of_iterations_cond): If type
        is POINTER_TYPE_P, use sizetype as step type instead of type.

        * gcc.dg/pr53550.c: New test.

--- gcc/tree-ssa-loop-niter.c.jj        2012-06-01 14:40:59.336398386 +0200
+++ gcc/tree-ssa-loop-niter.c   2012-06-01 17:52:09.128317401 +0200
@@ -1275,13 +1275,14 @@ number_of_iterations_cond (struct loop *
      practice, but it is simple enough to manage.  */
   if (!integer_zerop (iv0->step) && !integer_zerop (iv1->step))
     {
+      tree step_type = POINTER_TYPE_P (type) ? sizetype : type;
       if (code != NE_EXPR)
        return false;
 
-      iv0->step = fold_binary_to_constant (MINUS_EXPR, type,
+      iv0->step = fold_binary_to_constant (MINUS_EXPR, step_type,
                                           iv0->step, iv1->step);
       iv0->no_overflow = false;
-      iv1->step = build_int_cst (type, 0);
+      iv1->step = build_int_cst (step_type, 0);
       iv1->no_overflow = true;
     }
 
--- gcc/testsuite/gcc.dg/pr53550.c.jj   2012-06-01 17:52:09.128317401 +0200
+++ gcc/testsuite/gcc.dg/pr53550.c      2012-06-02 08:53:53.345935193 +0200
@@ -0,0 +1,12 @@
+/* PR tree-optimization/53550 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fprefetch-loop-arrays -w" } */
+
+int *
+foo (int *x)
+{
+  int *a = x + 10, *b = x, *c = a;
+  while (b != c)
+    *--c = *b++;
+  return x;
+}

        Jakub