This is the mail archive of the
mailing list for the GCC project.
Re: i386 PATCH for target/13685
On Fri, Sep 08, 2006 at 08:14:37PM -0700, Mark Mitchell wrote:
> Jason Merrill wrote:
> >H. J. Lu wrote:
> >>On Thu, Sep 07, 2006 at 08:26:45PM -0400, Jason Merrill wrote:
> >>>The testcase in 13685 breaks because -Os implies a smaller
> >>>PREFERRED_STACK_BOUNDARY than SSE requires. This patch causes us to
> >>>use the 128-bit boundary if SSE is enabled, which fixes the bug.
> >>I think it is a bad idea for -Os to change ABI. There are several bugs
> >>open because of it. You can have a program compiled with -Os calling
> >>a library compiled with -msee. The program will crash since -Os
> >>uses a different ABI. The easiest way to fix is for -Os not to change
> >>the ABI automatically.
> >I wouldn't mind changing the stack boundary to always be 128 bits.
> FWIW, I would strongly suggest that we use a fixed ABI independent of
> -Os, i.e., change the stack boundary to always be 128 bits. I believe
> that it should always be the case that code compiled with different -O
> options can be freely intermixed (whereas -f/-m options may change the ABI).