[PATCH] D19760: [AArch64] Turn on "aarch64-ssa-load-store-opt" by default

[Jongwon Lee via llvm-commits]

JongwonLee added a comment.

In http://reviews.llvm.org/D19760#419206, @rengolin wrote:

> This is not just for SPEC. 10% build time regression in an important
>  benchmark with no performance improvement is a bad thing. The
>  improvements on the test-suite also show too small a margin to justify
>  such a big compiler-time regression.
>
> If this was 2012, when Clang was 40~60% faster than GCC, I'd be ok
>  with the change once you can prove there's a relevant benchmark out
>  there that benefits immensely. So far, I haven't seen any evidence.
>
> But right now, our compile time for most workloads have gone worse
>  than GCC, and 10% is a very big deal, especially now that James wants
>  to see the validity of this pass to other AArch64 cores.
>
> Finally, such a big hit on compile time for a small back-end pass may
>  be an indication that you're doing something wrong. There may be a
>  much easier and faster way to do what you want, and I suggest you work
>  with James to make sure that situation improves.
>
> cheers,
> --renato


Thank you for the description.


http://reviews.llvm.org/D19760