Richard Guenther wrote: > This is a proposal to introduce an optimization level -Ofast > that can collect (target specific) optimization flags that > can affect runtime behavior such as -funsafe-math-optimizations > or -mrecip.
I think that makes sense. Defining what's allowed in these cases is always tricky (there was a long thread a couple of years back in which we tried to get some scoping on just what -ffast-math might be allowed to do), but I think the short answer is "this option will try to make your program go faster, even if that means doing things the standards do not allow the compiler to do". > Currently none of the standard optimization levels have this > kind of affect and we should not change that (people might > argue that -funsafe-math-optimizations can go into -O3). I agree that -O3 should not violate the standards. However, I don't agree that it shouldn't be target-specific. (It's quite possible that we agree; I'm interpreting your words.) If there's a magic option that makes MIPS go faster but makes Power go slower, then -O3 on MIPS should most definitely turn it on, and -O3 on Power most definitely should not. As a user, I don't want to know about the option; I just want -O3 to generate fast code. -- Mark Mitchell CodeSourcery m...@codesourcery.com (650) 331-3385 x713
