[PATCH] D18890: [AArch64] add SSA Load Store optimization pass

[Jongwon Lee via llvm-commits]

JongwonLee added a comment.

In http://reviews.llvm.org/D18890#420988, @jmolloy wrote:

> In http://reviews.llvm.org/D18890#418230, @JongwonLee wrote:
>
> > In http://reviews.llvm.org/D18890#417820, @jmolloy wrote:
> >
> > > Hi,
> > >
> > > So why aren't you doing this in codegen prepare or dag combine?
> > >
> > > Cheers,
> > >
> > > James
> >
> >
> > Hi,
> >  I didn't try this work on other positions except backend.
> >  As I mentioned before, this work is only considering AArch64 not other backends.
> >  Is there any advantages of doing this work on codegen prepare or dag combine?
>
>
> Hi Jongwon,
>
> Sure, there are advantages. Modifying IR is substantially easier and less prone to error than modifying machine instructions. This is also a generic optimization fixing a problem that likely affects more than just the AArch64 target, therefore the right thing to do is to implement it in such a way that it will benefit other targets (unless that causes a very high cost).
>
> In this case it would seem to me quicker, easier and less technical debt later to implement this higher up in the compiler.
>
> James


Hi James
Thank you for the advice.
I'll try to do this in higher level in the compiler.

Jongwon


http://reviews.llvm.org/D18890