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From: "amylaar at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/29347] New: i386 mode switching clobbers fp exception handling bits Date: Wed, 04 Oct 2006 15:29:00 -0000 [thread overview] Message-ID: <bug-29347-5394@http.gcc.gnu.org/bugzilla/> (raw) The mode switching for floating point rounding that the i386 backend does does not actually place mode switches, but rather the calculation of values used for mode switches. Not only does that defeat the purpose of doing lazy code motion of the mode switches themselves (this problem could easily be remedied by handling the actual mode switches as a separate entity), it also leads to information in the floating point control register being clobbered if the user changes it (e.g. with feenableexcept: http://www.gnu.org/software/libc/manual/html_node/Control-Functions.html) between the calculation of the value used for a mode switch, and the point where a mode switch actually takes place. -- Summary: i386 mode switching clobbers fp exception handling bits Product: gcc Version: 4.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: amylaar at gcc dot gnu dot org GCC target triplet: i386-*-* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29347
next reply other threads:[~2006-10-04 15:29 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2006-10-04 15:29 amylaar at gcc dot gnu dot org [this message] 2006-10-04 16:50 ` [Bug target/29347] " amylaar at gcc dot gnu dot org 2006-10-05 7:51 ` uros at kss-loka dot si 2006-10-09 10:28 ` rguenth at gcc dot gnu dot org 2006-10-23 12:10 ` amylaar at gcc dot gnu dot org
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