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[Bug tree-optimization/32663] [4.3 regression]: revision 126369 went into an infinite loop
- From: "hjl at lucon dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 7 Jul 2007 16:54:11 -0000
- Subject: [Bug tree-optimization/32663] [4.3 regression]: revision 126369 went into an infinite loop
- References: <bug-32663-682@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #5 from hjl at lucon dot org 2007-07-07 16:54 -------
Before the change, PRE generates:
# prephitmp.165_1394 = PHI <storetmp.156_472(127), storetmp.156_452(130)>
# prephitmp.165_1395 = PHI <storetmp.156_1216(127), storetmp.156_466(130)>
# nlast_26 = PHI <0(127), nlast_442(130)>
# lasp_21 = PHI <1(127), lasp_454(130)>
D.1457_436 = prephitmp.165_1395;
ii.62_440 = ii;
D.1361_441 = ii.62_440 + -1;
nlast_442 = (*iwhi_303(D))[D.1361_441];
D.1459_443 = nlast_442 + -1;
D.1460_444 = D.1459_443 * nlast_442;
D.1461_445 = D.1460_444 / 2;
D.1462_446 = D.1457_436 + D.1461_445;
storetmp.156_466 = D.1462_446;
*nswe_430(D) = D.1462_446;
D.1463_447 = prephitmp.165_1394;
D.1464_448 = D.1463_447 + 1;
storetmp.156_452 = D.1464_448;
*ncat_431(D) = D.1464_448;
D.1466_451 = nlast_26 + lasp_21;
(*inat_192(D))[D.1463_447] = D.1466_451;
D.1465_453 = prephitmp.165_1394;
After change, PRE generates:
# prephitmp.165_1395 = PHI <storetmp.156_1216(127), storetmp.156_466(130)>
# nlast_26 = PHI <0(127), nlast_442(130)>
# lasp_21 = PHI <1(127), lasp_454(130)>
D.1457_436 = prephitmp.165_1395;
ii.62_440 = ii;
D.1361_441 = ii.62_440 + -1;
nlast_442 = (*iwhi_303(D))[D.1361_441];
D.1459_443 = nlast_442 + -1;
D.1460_444 = D.1459_443 * nlast_442;
D.1461_445 = D.1460_444 / 2;
D.1462_446 = D.1457_436 + D.1461_445;
storetmp.156_466 = D.1462_446;
*nswe_430(D) = D.1462_446;
D.1463_447 = D.1465_453;
D.1464_448 = D.1463_447 + 1;
*ncat_431(D) = D.1464_448;
D.1466_451 = nlast_26 + lasp_21;
(*inat_192(D))[D.1463_447] = D.1466_451;
D.1465_453 is never initialized.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32663