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Re: On the x86_64, does one have to zero a vector register before filling it completely ?
- From: Toon Moene <toon at moene dot org>
- To: tprince at computer dot org, gcc mailing list <gcc at gcc dot gnu dot org>
- Date: Sat, 28 Nov 2009 20:03:39 +0100
- Subject: Re: On the x86_64, does one have to zero a vector register before filling it completely ?
- References: <4B1107A6.6010205@moene.org> <4B113B18.5070304@aol.com>
Tim Prince wrote:
> If you want those, you must request them with -mtune=barcelona.
OK, so it is an alignment issue (with -mtune=barcelona):
.L6:
movups 0(%rbp,%rax), %xmm0
movups (%rbx,%rax), %xmm1
incl %ecx
addps %xmm1, %xmm0
movaps %xmm0, (%r8,%rax)
addq $16, %rax
cmpl %r10d, %ecx
jb .L6
Thanks,
--
Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
Saturnushof 14, 3738 XG Maartensdijk, The Netherlands
At home: http://moene.org/~toon/
Progress of GNU Fortran: http://gcc.gnu.org/gcc-4.5/changes.html