public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
* [Bug c/23657] New: Wrong code generated: too much optimized out @ 2005-08-31 16:05 qrczak at knm dot org dot pl 2005-08-31 16:23 ` [Bug tree-optimization/23657] [4.1 Regression] " pinskia at gcc dot gnu dot org ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: qrczak at knm dot org dot pl @ 2005-08-31 16:05 UTC (permalink / raw) To: gcc-bugs /* The result should be 7. When compiled with gcc version 4.1.0 20050815 (experimental) with some patches from PLD (incl. PR7776, PR20297, PR23128, PR22533, PR23386) with -O, the result is 0. */ #include <stdio.h> int arr[100]; int *alloc(void) {return arr;} void fill(int n) { int *result = alloc(); int *dest = result; for(;;) { int *next; dest[0] = 7; if (--n == 0) break; next = dest + 1; dest = next; } } int main(void) { fill(5); printf("%d\n", arr[1]); return 0; } /* Looking at the generated assembly code, the whole loop is optimized out, except for filling the first element. Using less temporaries or inlining alloc() makes the bug disappear. The bug manifests only with optimization turned on. */ -- Summary: Wrong code generated: too much optimized out Product: gcc Version: 4.1.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: qrczak at knm dot org dot pl CC: gcc-bugs at gcc dot gnu dot org GCC build triplet: i686-pc-linux-gnu GCC host triplet: i686-pc-linux-gnu GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23657 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/23657] [4.1 Regression] Wrong code generated: too much optimized out 2005-08-31 16:05 [Bug c/23657] New: Wrong code generated: too much optimized out qrczak at knm dot org dot pl @ 2005-08-31 16:23 ` pinskia at gcc dot gnu dot org 2005-08-31 22:14 ` qrczak at knm dot org dot pl ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-08-31 16:23 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From pinskia at gcc dot gnu dot org 2005-08-31 16:19 ------- Confirmed, between t41.copyrename2 and t42.dom2, the V_MAY_DEF is removed. After *next_8 = 7; Before: # TMT.51_18 = V_MAY_DEF <TMT.51_4>; *dest_2 = 7; I think we are forgetting to copy the alias info. I think this is fixed by the patch for PR 23509: http://gcc.gnu.org/ml/gcc-patches/2005-08/msg01647.html The tree-cfg.c part that is. -- What |Removed |Added ---------------------------------------------------------------------------- CC| |pinskia at gcc dot gnu dot | |org Status|UNCONFIRMED |NEW Component|c |tree-optimization Ever Confirmed| |1 GCC build triplet|i686-pc-linux-gnu | GCC host triplet|i686-pc-linux-gnu | GCC target triplet|i686-pc-linux-gnu | Keywords| |alias, wrong-code Last reconfirmed|0000-00-00 00:00:00 |2005-08-31 16:19:38 date| | Summary|Wrong code generated: too |[4.1 Regression] Wrong code |much optimized out |generated: too much | |optimized out Target Milestone|--- |4.1.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23657 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/23657] [4.1 Regression] Wrong code generated: too much optimized out 2005-08-31 16:05 [Bug c/23657] New: Wrong code generated: too much optimized out qrczak at knm dot org dot pl 2005-08-31 16:23 ` [Bug tree-optimization/23657] [4.1 Regression] " pinskia at gcc dot gnu dot org @ 2005-08-31 22:14 ` qrczak at knm dot org dot pl 2005-08-31 22:23 ` qrczak at knm dot org dot pl 2005-08-31 22:23 ` pinskia at gcc dot gnu dot org 3 siblings, 0 replies; 5+ messages in thread From: qrczak at knm dot org dot pl @ 2005-08-31 22:14 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From qrczak at knm dot org dot pl 2005-08-31 22:11 ------- > I think this is fixed by the patch for PR 23509: > http://gcc.gnu.org/ml/gcc-patches/2005-08/msg01647.html Indeed, applying this patch and recompiling gcc fixed the bug. Thanks. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23657 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/23657] [4.1 Regression] Wrong code generated: too much optimized out 2005-08-31 16:05 [Bug c/23657] New: Wrong code generated: too much optimized out qrczak at knm dot org dot pl 2005-08-31 16:23 ` [Bug tree-optimization/23657] [4.1 Regression] " pinskia at gcc dot gnu dot org 2005-08-31 22:14 ` qrczak at knm dot org dot pl @ 2005-08-31 22:23 ` qrczak at knm dot org dot pl 2005-08-31 22:23 ` pinskia at gcc dot gnu dot org 3 siblings, 0 replies; 5+ messages in thread From: qrczak at knm dot org dot pl @ 2005-08-31 22:23 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From qrczak at knm dot org dot pl 2005-08-31 22:23 ------- *** This bug has been marked as a duplicate of 23509 *** -- What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |DUPLICATE http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23657 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/23657] [4.1 Regression] Wrong code generated: too much optimized out 2005-08-31 16:05 [Bug c/23657] New: Wrong code generated: too much optimized out qrczak at knm dot org dot pl ` (2 preceding siblings ...) 2005-08-31 22:23 ` qrczak at knm dot org dot pl @ 2005-08-31 22:23 ` pinskia at gcc dot gnu dot org 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-08-31 22:23 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From pinskia at gcc dot gnu dot org 2005-08-31 22:14 ------- (In reply to comment #2) > Indeed, applying this patch and recompiling gcc fixed the bug. Thanks. Thanks for trying the patch. I only thought about this patch because of the symptom was about the same as other bug was. -- What |Removed |Added ---------------------------------------------------------------------------- URL| |http://gcc.gnu.org/ml/gcc- | |patches/2005- | |08/msg01647.html Keywords| |patch http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23657 ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2005-08-31 22:23 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2005-08-31 16:05 [Bug c/23657] New: Wrong code generated: too much optimized out qrczak at knm dot org dot pl 2005-08-31 16:23 ` [Bug tree-optimization/23657] [4.1 Regression] " pinskia at gcc dot gnu dot org 2005-08-31 22:14 ` qrczak at knm dot org dot pl 2005-08-31 22:23 ` qrczak at knm dot org dot pl 2005-08-31 22:23 ` pinskia at gcc dot gnu dot org
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).