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Re: PATCH [1/n] addr32: Properly use Pmode and word_mode
- From: Uros Bizjak <ubizjak at gmail dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: gcc-patches at gcc dot gnu dot org, Richard Henderson <rth at redhat dot com>
- Date: Sat, 12 Nov 2011 18:32:14 +0100
- Subject: Re: PATCH [1/n] addr32: Properly use Pmode and word_mode
- References: <20111112021931.GA26507@intel.com>
On Sat, Nov 12, 2011 at 3:19 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> The current x32 implementation uses LEAs to convert 32bit address to
> 64bit. ?However, we can use addr32 prefix to use 32bit address directly.
> It improves performance by 5% in SPEC CPU 2K/2006. ?All changes are done
> in x86 backend, except for a smaill unwind library assert change:
>
> http://gcc.gnu.org/ml/gcc-patches/2011-11/msg01555.html
>
> due to return column size difference.
>
> For x86-64, Pmode can be 32bit or 64bit, but word_mode is always 64bit.
> push/pop only work on word_mode. ?Also string instructions take Pmode
> pointers.
>
> I will submit a set of patches to use 32bit Pmode for x32. ?This is
> the first patch to properly use Pmode and word_mode. ?It also adds
> addr32 prefix to string instructions if needed. ?OK for trunk?
Not for stage3.
Uros.