This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug tree-optimization/31169] Bootstrap comparison error at revision 122821
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 15 Mar 2007 17:19:58 -0000
- Subject: [Bug tree-optimization/31169] Bootstrap comparison error at revision 122821
- References: <bug-31169-276@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #10 from rguenth at gcc dot gnu dot org 2007-03-15 17:19 -------
Now what is interesting despite of being wrong or not is that we use an
index only for the MEM ref:
<L11>:;
D.1641_16 = D.1589_4 + -1;
D.1642_15 = ®exp_3(D)->regexp.oneof.regexps[D.1641_16];
ivtmp___31_21 = (long unsigned int) D.1642_15;
# ivtmp___31_1 = PHI <ivtmp___31_12(5), ivtmp___31_21(7)>
# i_18 = PHI <i_11(5), i_5(7)>
<L2>:;
D.1592_10 = MEM[index: ivtmp___31_1];
process_alts_for_forming_states (D.1592_10);
i_11 = i_18 + -1;
if (i_11 >= 0) goto <L0>; else goto <L4>;
the stage2 compiler then derives a loop trip count based on the size of
the regexp->regexp.oneof.regexps[] array it seems (a size of 3 actually)
and replaces the induction variable by the MEM index.
This doesn't look like a wrong transformation, but I fail to see how
this could be different from the stage1 and stage2 compiler.
Zdenek, are we supposed to get a index-only mem-ref?
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rakdver at gcc dot gnu dot
| |org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31169