[PATCH] PR gold/17640

[Ilya Tocar]

On 18 Feb 07:48, H.J. Lu wrote:
> On Wed, Feb 18, 2015 at 7:00 AM, Ilya Tocar <tocarip.intel@gmail.com> wrote:
> > On 02 Feb 06:41, H.J. Lu wrote:
> >> On Mon, Feb 2, 2015 at 5:47 AM, Ilya Tocar <tocarip.intel@gmail.com> wrote:
> >> > Hi,
> >> >
> >> > This patch adds mov to lea conversion to gold (as discussed in PR).
> >> > It provides about 1.5% performance gain on SPEC2000 geomean,
> >> > when pie is used.
> >> > OK for trunk?
> >>
> >> The patch is incomplete.  Gold generates a useless R_386_RELATIVE
> >> relocation together with an unused GOT slot:
> >>
> >
> > I've tried to implement this, however I've encountered some difficulties.
> > It looks like not creating got slots/relocation in
> > Target_i386::Scan::local for  R_386_GOT32 (that will be converted to
> > R_386_GOTOFF later) is the right approach.
> > However in Scan::local we don't have access to corresponding view, and so we are
> > unable to check wether we are dealing with mov (which can be optimized),
> > or something else.
> > Can you provide some advice on how to check for mov's in scan?
> 
> Can you add access to view in Scan::local?
>
Scan::local is called from gold::scan_relocs, so passing view into it
will require changes in other targets, which I'd like to avoid.
Also I'm not sure how to get view into instruction that uses
corresponding relocation.