On Feb 5, 2014, at 3:06 PM, David Laight <da...@l8s.co.uk> wrote: > On Wed, Feb 05, 2014 at 11:09:05PM +0100, Joerg Sonnenberger wrote: >> On Wed, Feb 05, 2014 at 06:52:22PM +0000, David Laight wrote: >>> Module Name: src >>> Committed By: dsl >>> Date: Wed Feb 5 18:52:22 UTC 2014 >>> >>> Modified Files: >>> src/sys/arch/amd64/conf: Makefile.amd64 >>> src/sys/arch/i386/conf: Makefile.i386 >>> >>> Log Message: >>> Change the compiler options to explicitly specify: >>> -mno-mmx -mno-sse -mno-avx -mno-80387 -mno-fp-ret-in-387 >>> Since no-sse implies no-sse2 that should ensure that the compiler really >>> doesn't emit any instructions that might trap trying to use the FPU. >>> On amd64 at least some of those are needed to stop the compiler >>> saving the registers to stack on every varargs function. >>> It might be that -mno-sse did that before. >> >> This breaks clang. Please do not depend on one SSE option disabling >> another. > > Without those flags I believe gcc might generate x87 instructions. > Quite possibly even for amd64. > See a very recent linux fix. > Try searching for: Disable generation of traditional x87 instructions
I think Joerg is saying put in -mno-sse2 since that is not disabled by -mno-sse when using clang.
