[llvm-commits] [PATCH] Rework bit/bits value resolving in tblgen

[Jakob Stoklund Olesen]

On Aug 30, 2012, at 9:16 AM, Michael Liao <michael.liao at intel.com> wrote:

> It makes tblgen runs slower. Here my test script
> 
>  time llvm-tblgen -I include -I lib/Target/X86 lib/Target/X86/X86.td
> -o /dev/null (or ARM)
> 
> for release build
>     w/o patch    with patch
> X86  0.584s        0.665s
> ARM  0.514s        0.623s
> 
> time is measured by selecting the middle one from 3 consecutive runs.

That's quite significant.

> VarBitInit reference may contributes the most as the way they are formed
> in the patch is 'getBit(Init, Bit)' and will result in more duplicated
> value resolving.

We already have way too much redundant resolving going on, and I think there is an opportunity to make TableGen a lot faster by fixing it.

Could I ask you to look at that? I'd rather not make it worse.

/jakob