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 David -- David Laight: da...@l8s.co.uk