On Wed, Apr 5, 2017 at 10:20 AM, Jakub Jelinek <ja...@redhat.com> wrote: > On Wed, Apr 05, 2017 at 10:12:02AM +0200, Uros Bizjak wrote: >> Oh, I forgot to point out that on x86_64 ABI specifies MMX values in >> SSE registers. > > I know it does. And if people have their own function that returns > __m64 or takes such arguments, they surely have to. > The question is only about the case when no function (in the assembly) > returns in SSE registers nor gets arguments in them, when all the > MMX code is inside of a function. > With your patch, it is - the MMX intrinsics are functions and we error on > them even when they are inlined. > With my patch we count only the non-inlined functions, something we emit > assembly for or call them from other TUs. > > If you think requiring SSE for MMX always in 64-bit code is fine, even > when not strictly needed (as in, you really don't need SSE ISA to execute > such code, although there are no CPUs without that HW), so be it, then > let's go with your patch.
Yes, I think that we should consistently warn even in case intrinsic is inlined. I'm afraid that otherwise we will have endless stream of bugreports that something warns with -O0, but not -O1+, when LTO is used, etc, etc... The rule is: When user uses (or intends to use) MMX value (that goes in SSE reg on x86_64), -msse is needed on x86_64, otherwise warning is emitted. Uros.
