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* [Bug rtl-optimization/20219] New: Missed optimisation sin / tan --> cos
@ 2005-02-26 22:27 christophe dot jaillet at wanadoo dot fr
2005-02-26 23:23 ` [Bug rtl-optimization/20219] " pinskia at gcc dot gnu dot org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: christophe dot jaillet at wanadoo dot fr @ 2005-02-26 22:27 UTC (permalink / raw)
To: gcc-bugs
GCC knows how to optimise
tan * cos --> sin (fold-const line 7734)
cos * tan --> sin
sin / cos --> tan (fold-const line 8080)
cos / sin --> 1.0 / tan (fold-const line 8094)
but misses
sin / tan --> cos
tan / sin --> 1.0 / cos
--
Summary: Missed optimisation sin / tan --> cos
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: rtl-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: christophe dot jaillet at wanadoo dot fr
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20219
^ permalink raw reply [flat|nested] 4+ messages in thread* [Bug rtl-optimization/20219] Missed optimisation sin / tan --> cos 2005-02-26 22:27 [Bug rtl-optimization/20219] New: Missed optimisation sin / tan --> cos christophe dot jaillet at wanadoo dot fr @ 2005-02-26 23:23 ` pinskia at gcc dot gnu dot org 2005-02-27 0:51 ` [Bug tree-optimization/20219] " pinskia at gcc dot gnu dot org 2005-02-27 4:09 ` uros at kss-loka dot si 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-02-26 23:23 UTC (permalink / raw) To: gcc-bugs -- What |Removed |Added ---------------------------------------------------------------------------- OtherBugsDependingO| |19987 nThis| | Severity|normal |enhancement Keywords| |missed-optimization http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20219 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/20219] Missed optimisation sin / tan --> cos 2005-02-26 22:27 [Bug rtl-optimization/20219] New: Missed optimisation sin / tan --> cos christophe dot jaillet at wanadoo dot fr 2005-02-26 23:23 ` [Bug rtl-optimization/20219] " pinskia at gcc dot gnu dot org @ 2005-02-27 0:51 ` pinskia at gcc dot gnu dot org 2005-02-27 4:09 ` uros at kss-loka dot si 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-02-27 0:51 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From pinskia at gcc dot gnu dot org 2005-02-26 01:13 ------- Confirmed, nice catch. -- What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Component|rtl-optimization |tree-optimization Ever Confirmed| |1 Last reconfirmed|0000-00-00 00:00:00 |2005-02-26 01:13:02 date| | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20219 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/20219] Missed optimisation sin / tan --> cos 2005-02-26 22:27 [Bug rtl-optimization/20219] New: Missed optimisation sin / tan --> cos christophe dot jaillet at wanadoo dot fr 2005-02-26 23:23 ` [Bug rtl-optimization/20219] " pinskia at gcc dot gnu dot org 2005-02-27 0:51 ` [Bug tree-optimization/20219] " pinskia at gcc dot gnu dot org @ 2005-02-27 4:09 ` uros at kss-loka dot si 2 siblings, 0 replies; 4+ messages in thread From: uros at kss-loka dot si @ 2005-02-27 4:09 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From uros at kss-loka dot si 2005-02-26 09:50 ------- Here is the patch to implement missing folds: http://gcc.gnu.org/ml/gcc-patches/2004-03/msg01024.html And here is the explanation why this transformation is not suitable for GCC even with -ffast-math: http://gcc.gnu.org/ml/gcc-patches/2004-03/msg01034.html -- What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |WONTFIX http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20219 ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2005-02-26 9:50 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2005-02-26 22:27 [Bug rtl-optimization/20219] New: Missed optimisation sin / tan --> cos christophe dot jaillet at wanadoo dot fr 2005-02-26 23:23 ` [Bug rtl-optimization/20219] " pinskia at gcc dot gnu dot org 2005-02-27 0:51 ` [Bug tree-optimization/20219] " pinskia at gcc dot gnu dot org 2005-02-27 4:09 ` uros at kss-loka dot si
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