------- Comment #17 from pinskia at gcc dot gnu dot org 2006-04-23 23:14
-------
Rewritting that loop like:
[kudzu:local/trunk/gcc] pinskia% svn diff tree-ssa-loop-niter.c
Index: tree-ssa-loop-niter.c
===================================================================
--- tree-ssa-loop-niter.c (revision 113199)
+++ tree-ssa-loop-niter.c (working copy)
@@ -1939,6 +1939,7 @@ scev_probably_wraps_p (tree type, tree b
tree unsigned_type, valid_niter;
tree base_plus_step, bpsps;
int cps, cpsps;
+ bool known_not_to_wrap;
/* FIXME: The following code will not be used anymore once
http://gcc.gnu.org/ml/gcc-patches/2005-06/msg02025.html is
@@ -2077,8 +2078,10 @@ scev_probably_wraps_p (tree type, tree b
estimate_numbers_of_iterations_loop (loop);
for (bound = loop->bounds; bound; bound = bound->next)
- if (proved_non_wrapping_p (at_stmt, bound, type, valid_niter))
- return false;
+ if (!proved_non_wrapping_p (at_stmt, bound, type, valid_niter))
+ known_not_to_wrap = false;
+ if (known_not_to_wrap)
+ return false;
/* At this point we still don't have a proof that the iv does not
overflow: give up. */
----------------------------
Makes it work, Now I am not going to say this is the "correct" fix or not.
What I am going to say, this is the most logical fix in that we know one iv can
not overflow does not mean all will not.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |spop at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26304
