| |||||||||||||
C as portable assemblerC as portable assemblerPosted May 31, 2011 18:05 UTC (Tue) by anton (guest, #25547)In reply to: C as portable assembler by jrn Parent article: What Every C Programmer Should Know About Undefined Behavior #3/3 The funny thing is that new gcc (at least up to 4.4) still generates code for signed addition that wraps around instead of code that traps on overflow. It's as if the aim of the gcc maintainers was to be least helpful to everyone: for the low-level coders, miscompile their code silently; for the specification pedants, avoid giving them ways to detect when they have violated the spec.
(Log in to post comments)
C as portable assembler Posted May 31, 2011 21:00 UTC (Tue) by jrn (subscriber, #64214) [Link]
There is -fwrapv and -ftrapv. If you think one of those should be the default, no doubt there are some other optimization tweaks (-fno-strict-aliasing?) that you also like; so I encourage you to work on an -Oanton switch in either a wrapper for gcc or gcc itself, for the sake of sharing.
I am pretty happy with -O2 for my own needs, since it generates fast code for loops, but I understand that different situations may involve different requirements and would be happy to live in a world with more people helping make the gcc UI more intuitive.
|
|||||||||||||