>>>>> "AC" == Adam Conrad <[email protected]> writes:
AC> On Thu, Mar 06, 2014 at 08:52:38PM -0500, Ryan Lortie wrote: >> >> fwiw, gnu99 doesn't stop the bug. You have to pick -std=c99 >> specifically. AC> Curious. You'd have to ask someone who works more with GCC upstream AC> to be sure, but I'd consider that I bug. I've always assumed and AC> treated gnuXX as a superset of cXX. It is intentional. Using -std=c99 on ia32 requires storing every float and double to ram and then reloading it to the registers in order to round it to 32 or 64 bits. For every calculation. Every function, every add/sub/mul/div, everything. That is SLOW. When the change first was made, there was enough heated complaing that gcc compromized by limiting it to just c99, and letting gnu99 continue to provide normal ia32 floating point. Just because someone may want some of the improvements in C99 doesn't imply that they want eliminate performance, too. When they do, they have -std=c99. And performance was /eliminated/. On the hardware I had at the time, a significant number of packages became unusably slow until the change was reverted for gnu99. Heterogeneous reproducability has value for some use cases, but the tiny differences in question are irrelevant to most floating point consumers. -JimC -- James Cloos <[email protected]> OpenPGP: 1024D/ED7DAEA6 -- ubuntu-devel mailing list [email protected] Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel
