This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: Potential issue with strstr on x86 with sse4.2 in glibc-2.18
- From: Alexander Monakov <amonakov at ispras dot ru>
- To: Rich Felker <dalias at aerifal dot cx>
- Cc: libc-alpha at sourceware dot org
- Date: Mon, 19 Aug 2013 21:34:10 +0400
- Subject: Re: Potential issue with strstr on x86 with sse4.2 in glibc-2.18
- References: <520E181D dot 2040308 at archlinux dot org> <alpine dot LNX dot 2 dot 00 dot 1308191628370 dot 2626 at monopod dot intra dot ispras dot ru> <20130819144648 dot GF20515 at brightrain dot aerifal dot cx> <alpine dot LNX dot 2 dot 00 dot 1308191924490 dot 2626 at monopod dot intra dot ispras dot ru> <20130819163712 dot GG20515 at brightrain dot aerifal dot cx> <alpine dot LNX dot 2 dot 00 dot 1308192045480 dot 2626 at monopod dot intra dot ispras dot ru> <20130819170550 dot GH20515 at brightrain dot aerifal dot cx>
On Mon, Aug 19, 2013 at 9:05 PM, Rich Felker <dalias@aerifal.cx> wrote:
> Yes, by default, but just because the default is -march=i486. This is
> not needed to avoid SSE alignment bugs, though, because GCC preserves
> the stack alignment mod 16 anyway unless you override that behavior.
I think sufficiently old GCC will not align mod 16. Incidentally, I
guess this is why this failure is observed: fglrx folks need to
produce a binary driver that works on ancient distros, and an easy way
to achieve that is to compile it on an ancient distro with an ancient
userland (and GCC) in the first place.