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Re: RFC: Can I require binutils 2.17 or above for AVX support in gcc?
- From: "Richard Guenther" <richard dot guenther at gmail dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: "Gcc Patch List" <gcc-patches at gcc dot gnu dot org>, "Ye, Joey" <joey dot ye at intel dot com>, "Guo, Xuepeng" <xuepeng dot guo at intel dot com>
- Date: Sun, 25 May 2008 11:49:02 +0200
- Subject: Re: RFC: Can I require binutils 2.17 or above for AVX support in gcc?
- References: <6dc9ffc80805241004j7184a092n110ab616e95a7eb3@mail.gmail.com>
On Sat, May 24, 2008 at 7:04 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> Hi,
>
> Binutils 2.17 and above supports both
>
> movq %rax, %xmm0
> movd %rax, %xmm0
>
> AVX has vmovq and no vmovd. To add AVX vmovq supportt to
> patterns with movd, I have 2 choices:
>
> 1. Add a new AVX pattern with vmovq. Or
> 2. Requiring binutils 2..17 or above, replace movd with
> %vmovq without adding a new pattern.
>
> Requiring binutils 2.17 or above also improves gcc code
> generation due to better linker. I certainly prefer #2. But I
> can live with #1.
>
> BTW, I can add "vmovd" to x86 assembler as the last resort.
You can note the restrictions with AVX in the target specific
install instructions and suggest to use binutils 2.17 or later there.
Richard.