On Wednesday 10 March 2010, Laurent Desnogues wrote: > Even if fast-math is known to break some rules, it only > breaks C rules IIRC. OTOH, NEON FP has no support > for NaN and other nice things from IEEE754.
And just checked gcc man page to verify this stuff. -ffast-math Sets -fno-math-errno, -funsafe-math-optimizations, -ffinite-math-only, -fno-rounding-math, -fno-signaling-nans and -fcx-limited-range. -ffinite-math-only Allow optimizations for floating-point arithmetic that assume that arguments and results are not NaNs or +-Infs. This option is not turned on by any -O option since it can result in incorrect output for programs which depend on an exact implementation of IEEE or ISO rules/specifications for math functions. It may, however, yield faster code for programs that do not require the guarantees of these specifications. So looks like -ffast-math already assumes no support for NaNs. Even if there are other nice IEEE754 things preventing NEON from being used with -ffast-math, an appropriate new option relaxing this requirement makes sense to be invented. -- Best regards, Siarhei Siamashka _______________________________________________ maemo-developers mailing list maemo-developers@maemo.org https://lists.maemo.org/mailman/listinfo/maemo-developers
