This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug tree-optimization/27441] New: VAR - 1 not identified as the same as VAR + -1
- From: "dann at godzilla dot ics dot uci dot edu" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 5 May 2006 02:21:08 -0000
- Subject: [Bug tree-optimization/27441] New: VAR - 1 not identified as the same as VAR + -1
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
It seems that neither FRE nor PRE can determine that stride.115 - 1 is the same
as stride.115 + -1 in the example below (taken from the comm3 function in mgrid
from SPEC2000). (Or am I missing something?)
<bb 2>:
stride.115 = *n;
stride.117 = stride.115 * stride.115;
offset.118 = ~stride.115 - stride.117;
D.1969 = stride.115 - 1;
if (D.1969 > 1) goto <L68>; else goto <L24>;
<L68>:;
pretmp.221 = stride.115 + -1;
pretmp.228 = offset.118 + pretmp.221;
pretmp.236 = offset.118 + stride.115;
i3 = 2;
--
Summary: VAR - 1 not identified as the same as VAR + -1
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: dann at godzilla dot ics dot uci dot edu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27441