re PR tree-optimization/43627 (slow compilation (tree canonical iv takes 75%))

2010-04-06  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/43627
	* tree-vrp.c (extract_range_from_unary_expr): Widenings
	of [1, +INF(OVF)] go to [1, +INF(OVF)] of the wider type,
	not varying.

	* gcc.dg/tree-ssa/vrp49.c: New testcase.

From-SVN: r157992

gcc/ChangeLog

+2010-04-06  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/43627
+	* tree-vrp.c (extract_range_from_unary_expr): Widenings
+	of [1, +INF(OVF)] go to [1, +INF(OVF)] of the wider type,
+	not varying.
+
 2010-04-06  Jakub Jelinek  <jakub@redhat.com>
 
 	* BASE-VER: Change to 4.6.0.

gcc/testsuite/ChangeLog

+2010-04-06  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/43627
+	* gcc.dg/tree-ssa/vrp49.c: New testcase.
+
 2010-04-06  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/43638

gcc/testsuite/gcc.dg/tree-ssa/vrp49.c

+/* { dg-do link } */
+/* { dg-options "-O2" } */
+
+extern void link_error (void) __attribute__((noreturn));
+int n;
+float *x;
+int main()
+{
+  if (n > 0)
+    {
+      int i = 0;
+      do
+	{
+	  long long index;
+	  i = i + 1;
+	  index = i;
+	  if (index <= 0)
+	    link_error ();
+	  x[index] = 0;
+	  i = i + 1;
+	  index = i;
+	  if (index <= 0)
+	    link_error ();
+	  x[index] = 0;
+	}
+      while (i < n);
+    }
+}

gcc/tree-vrp.c

@@ -2715,8 +2715,16 @@ extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
 	   || vr0.type == VR_ANTI_RANGE)
 	  && TREE_CODE (vr0.min) == INTEGER_CST
 	  && TREE_CODE (vr0.max) == INTEGER_CST
-	  && !is_overflow_infinity (vr0.min)
-	  && !is_overflow_infinity (vr0.max)
+	  && (!is_overflow_infinity (vr0.min)
+	      || (vr0.type == VR_RANGE
+		  && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
+		  && needs_overflow_infinity (outer_type)
+		  && supports_overflow_infinity (outer_type)))
+	  && (!is_overflow_infinity (vr0.max)
+	      || (vr0.type == VR_RANGE
+		  && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
+		  && needs_overflow_infinity (outer_type)
+		  && supports_overflow_infinity (outer_type)))
 	  && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
 	      || (vr0.type == VR_RANGE
 		  && integer_zerop (int_const_binop (RSHIFT_EXPR,
@@ -2730,6 +2738,10 @@ extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
 	  new_max = force_fit_type_double (outer_type,
 					   TREE_INT_CST_LOW (vr0.max),
 					   TREE_INT_CST_HIGH (vr0.max), 0, 0);
+	  if (is_overflow_infinity (vr0.min))
+	    new_min = negative_overflow_infinity (outer_type);
+	  if (is_overflow_infinity (vr0.max))
+	    new_max = positive_overflow_infinity (outer_type);
 	  set_and_canonicalize_value_range (vr, vr0.type,
 					    new_min, new_max, NULL);
 	  return;