[Bug c++/38045] New: floating point exception triggered incorrectly
GCC version and linux distribution: g++ (Gentoo 4.3.2 p1.1) 4.3.2 g++ (GCC) 4.3.0 20080428 (Red Hat 4.3.0-8) g++ (Ubuntu 4.3.2-1ubuntu11) 4.3.2 Command line to trigger bug: g++ crash.cpp -O2 Compiler output: (none) Executable input: ./a.out Executable output: Floating point exception Source file attached along with preprocessed file -- Summary: floating point exception triggered incorrectly Product: gcc Version: 4.3.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: cstankevitz at toyon dot com http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38045
[Bug c++/38045] floating point exception triggered incorrectly
--- Comment #1 from cstankevitz at toyon dot com 2008-11-07 05:48 --- Created an attachment (id=16630) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16630&action=view) Source -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38045
[Bug c++/38045] floating point exception triggered incorrectly
--- Comment #2 from cstankevitz at toyon dot com 2008-11-07 05:48 --- Created an attachment (id=16631) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16631&action=view) Preprocessed source -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38045
[Bug c++/38045] floating point exception triggered when it shouldn't be
--- Comment #3 from cstankevitz at toyon dot com 2008-11-07 05:50 --- BTW, the invalid floating point exception is not triggered in g++-4.1.2 (GCC) 4.1.2 (Gentoo 4.1.2 p1.1) -- cstankevitz at toyon dot com changed: What|Removed |Added Summary|floating point exception|floating point exception |triggered incorrectly |triggered when it shouldn't ||be http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38045
[Bug c++/38045] floating point exception triggered when it shouldn't be
--- Comment #5 from cstankevitz at toyon dot com 2008-11-07 07:01 --- I should have added... the three instances of crashing are on 64 bit OS. The gentoo example above: [EMAIL PROTECTED] ~/delete $ uname -a Linux crs 2.6.25-gentoo-r7 #17 SMP Sun Nov 2 12:50:21 PST 2008 x86_64 Intel(R) Core(TM)2 Quad CPU Q9650 @ 3.00GHz GenuineIntel GNU/Linux -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38045
[Bug c++/38045] floating point exception triggered when it shouldn't be
--- Comment #8 from cstankevitz at toyon dot com 2008-11-07 07:44 --- Any recommendation on how to work around it with GCC 4.3.2? Seemingly unrelated code changes make it go away. Thanks - Chris. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38045
[Bug c++/46806] New: -O3 implies 0 <= 8 <= 7
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46806 Summary: -O3 implies 0 <= 8 <= 7 Product: gcc Version: 4.5.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ AssignedTo: unassig...@gcc.gnu.org ReportedBy: cstankev...@toyon.com Host: Linux seymour.toyon.corp 2.6.35.6-48.fc14.x86_64 #1 SMP Fri Oct 22 15:36:08 UTC 2010 x86_64 x86_64 x86_64 GNU/Linux Build: g++ (GCC) 4.5.1 20100924 (Red Hat 4.5.1-4) Created attachment 22636 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22636 sample program Linux seymour.toyon.corp 2.6.35.6-48.fc14.x86_64 #1 SMP Fri Oct 22 15:36:08 UTC 2010 x86_64 x86_64 x86_64 GNU/Linux g++ (GCC) 4.5.1 20100924 (Red Hat 4.5.1-4) Compile the attached source with "g++ test.cpp -O3" and the executable will report 0<=8<=7. To make the strange result go away: - comment out the do-nothing line gValue = EdgeType (or make a number of other minor changes) - compile with -O1
[Bug c++/46806] -O3 implies 0 <= 8 <= 7
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46806 --- Comment #2 from Chris Stankevitz 2010-12-05 02:47:51 UTC --- > 8 is out of range of the enum. I agree. Unfortunately, with -O3, 8 is reported as in the range.
[Bug c++/46806] -O3 implies 0 <= 8 <= 7
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46806 Chris Stankevitz changed: What|Removed |Added Attachment #22636|0 |1 is obsolete|| --- Comment #3 from Chris Stankevitz 2010-12-05 02:53:17 UTC --- Created attachment 22637 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22637 sample program Updated sample to use a cast to explicitly compare signed ints.
[Bug c++/46806] -O3 implies 0 <= 8 <= 7
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46806
--- Comment #7 from Chris Stankevitz 2010-12-05
18:11:55 UTC ---
If I understand correctly, you are saying "The following is not a valid way to
test whether a user-supplied int is withing the bounds of an enum:"
if (
Eight >= static_cast(eZero) &&
Eight <= static_cast(eSeven))
{
Value = static_cast(Eight);
std::cerr << "0 <= 8 <= 7 (this is bad)\n";
}
What is the correct, valid, portable way to test whether a user-supplied int is
in the range of an enum?
Thank you,
Chris
[Bug c++/46806] -O3 implies 0 <= 8 <= 7
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46806 Chris Stankevitz changed: What|Removed |Added Status|ASSIGNED|RESOLVED Resolution||INVALID --- Comment #10 from Chris Stankevitz 2010-12-05 23:47:19 UTC --- > The comparisons are ok, with or without casts, I think the problem > is this line: > Value = static_cast(Eight); I disagree because the problem exists even if that line is this more reasonable statement: Value = static_cast(eZero);
