On Mon, Dec 04, 2017 at 01:15:46AM -0700, Jan Beulich wrote: > >>> On 02.12.17 at 01:13, <ja...@redhat.com> wrote: > > On Fri, Dec 01, 2017 at 02:54:28PM +0100, Jakub Jelinek wrote: > >> Will try this: > > > > That failed to bootstrap, but here is an updated version that passed > > bootstrap/regtest on x86_64-linux and i686-linux, ok for trunk? > > Thanks for the quick fix. A related question though: The issue > could have been spotted (in the provided example) by gas, if > only it had been given enough information (i.e. that AVX512VL > insns are fine to use, but AVX512DQ ones aren't). Is there a > reason gcc doesn't pass any -march= to gas, nor issues any > .arch directives?
Because we've never done that on i?86/x86_64, so it would confuse users, plus there can be instructions in inline asm, there is target attribute, function multiversioning, etc. A year or more ago I've been regtesting with hacks to let the assembler complain, I just remember it wasn't that easy, but don't remember the details anymore. Jakub