On Tue, Oct 31, 2017 at 11:17:52AM +0100, Jason A. Donenfeld wrote: > Hi folks, > > Older versions of gcc are horrible for int128_t on aarch64, emitting a > __multi3 call, which is slow and defeats the purpose. However, more > recent versions of gcc (since 5, IIRC), do the right thing and produce > the proper inlined instructions. > > Do we have the infrastructure available to test for this, and > conditionally set CONFIG_ARCH_SUPPORTS_INT128 if we do?
Judging by Documentation/kbuild/makefiles.txt, we could do something like the below in the arm64 Makefile: cflags-y += $(call cc-ifversion, -ge, 0500, -DCONFIG_ARCH_SUPPORTS_INT128) Note that I havent tested this at all. Thanks,
