Possible advantage

Posted Jun 17, 2008 21:38 UTC (Tue) by roelofs (guest, #2599)
In reply to: Possible advantage by giraffedata
Parent article: Implications of pure and constant functions

But when I debug at the machine level I add -O0 to the compile options. That's usually described as "don't optimize", but as I consider optimization to be an integral part of the compiler's job, I view it as, "Make the machine program track the source code as closely as possible."

"...and watch your bug go away." :-)

That seems to happen to me more often than not. Most recently it turned out to be a gcc code-generation bug, 32-bit only, 3.4.x only. (Pretty sure not related to const, though C++ is a different beast, so I'm not 100% certain.)

Greg

Possible advantage

Posted Jun 18, 2008 2:00 UTC (Wed) by giraffedata (guest, #1954) [Link]

Of all the bugs I've analyzed with GDB, I'd say about 5% stop manifesting when I disable optimization. One was a compiler optimizer bug, one was me lying to the compiler (unintentionally, of course), and the rest were wild pointers causing stack corruption.

Of course, this is mostly with older compilers. (The new ones are too slow for me).