https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101865
--- Comment #9 from HaoChen Gui <guihaoc at gcc dot gnu.org> --- (In reply to Tulio Magno Quites Machado Filho from comment #7) > (In reply to HaoChen Gui from comment #6) > > Does _ARCH_PWR8 impact anything during the compiling? > > I can answer this question from an user point of view. It's used in many > projects to indicate if the target processor supports certain features, e.g. > > #ifdef _ARCH_PWR8 > asm (...); /* Power8-specific code. */ > #else > /* Generic implementation. */ > ... > #endif For this example, let's suppose that we set mcpu=power8 and mno-vsx in the command line. Thus, _ARCH_PWR8 should be defined as mcpu=power8. But if the Power8-specific codes contain VSX codes, could the asm be executed? I think we just use the macro _ARCH_PWR8 here to guard which instructions are available.
