------- Comment #5 from ian at airs dot com 2007-03-26 18:27 -------
I'm testing this patch.
Index: tree-vrp.c
===================================================================
--- tree-vrp.c (revision 123218)
+++ tree-vrp.c (working copy)
@@ -1982,10 +1982,18 @@ extract_range_from_binary_expr (value_ra
return;
}
+ /* We punt if:
+ 1) [-INF, +INF]
+ 2) [-INF, +-INF(OVF)]
+ 3) [+-INF(OVF), +INF]
+ 4) [+-INF(OVF), +-INF(OVF)]
+ We learn nothing when we have INF and INF(OVF) on both sides.
+ Note that we do accept [-INF, -INF] and [+INF, +INF] without
+ overflow. */
if ((min == TYPE_MIN_VALUE (TREE_TYPE (min))
- || is_negative_overflow_infinity (min))
+ || is_overflow_infinity (min))
&& (max == TYPE_MAX_VALUE (TREE_TYPE (max))
- || is_positive_overflow_infinity (max)))
+ || is_overflow_infinity (max)))
{
set_value_range_to_varying (vr);
return;
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31345
