Hello Vera, On 28 Nov 2013, at 13:15, Vera Loeser wrote:
> I use the GCC 4.8 from Macports and I'd like to optimize my code by using the > flag -march=native. For that I have to use the assembler of clang, because > the GNU assembler is too old and cannot use the AVX extensions. By setting > the flags "-Wa,-q" the GCC should work. But with optimizing loops there are > some problems: > > /var/folders/zz/q_423dms0vqcgp5khshwwrwh000142/T//cchZfZOX.s:232771:2: > error: ambiguous instructions require an explicit suffix (could be > 'fisttps', or 'fisttpl') > fisttp 62(%rsp) > > I think the GCC generates as code, which is too imprecise for the clang > compiler. > Is there a way to get more precise code to use the -march=native flag? At this time, using "llvm-mc" (or clang -cc1as) directly from GCC requires non-trivial changes to the configuration. I have a patch-in-progress to address this, but it is not yet ready - and, in the short-term, I don't think there is any simple work-around. Please file a bug requesting the enhancement, and I will copy the list when the patch is ready for testing, thanks. Iain
