Re: CVS commit: src/sys/arch

[David Laight <david%l8s.co.uk@localhost>]

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: david%l8s.co.uk@localhost