[llvm-commits] [PATCH] PERF: Reuse data fragments while lowering

[Rafael Espíndola]

> Most of the time, nothing ever gets invalidated.
> When two fragments are coalesced, they are combined into one fragment whose
> total size is equal to the sum of the sizes of the original two. So the
> addresses of later fragments won't change. Nothing needs to be invalidated
> unless Dst happens to be the LastValidFragment. (in which case, only Dst is
> invalidated).

Got it.

> I ran my own test on a 1,000,000 line .s file ... there was too much random
> variance to measure a statistically significant difference. The assembler is
> already so fast... the greatest advantage of this patch may be reduced
> memory usage.

If nothing else it makes debugging LayoutOnce faster :-)

LGTM.

> Thanks,
>  - David Meyer

Cheers,
Rafael