[PATCH] D89264: [LICM] Make promotion faster

Mon Oct 12 14:35:05 PDT 2020

lebedev.ri added a comment.

In D89264#2326088 <https://reviews.llvm.org/D89264#2326088>, @nikic wrote:

> In D89264#2325990 <https://reviews.llvm.org/D89264#2325990>, @lebedev.ri wrote:
>
>> An ignorant word of caution: anything can be made faster by making it do less stuff.
>>
>>> There's no code-size impact on any of the CTMark programs, so code quality impact of the change should be low.
>>
>> That doesn't really sound like exhaustive-enough test coverage to me.
>
> Yes, of course :) I have checked this on the full test-suite now, and there are no codegen differences with this patch. The only differences in statistics are...

I guess i was thinking of even bigger coverage (SPEC?, but i personally don't have it (either?)).

>   basicaa.SearchLimitReached | 146199 | 128184
>   basicaa.SearchTimes | 50855724 | 23825700
>   memory-builtins.ObjectVisitorArgument | 331614 | 254610
>   memory-builtins.ObjectVisitorLoad | 149739 | 81225
>
> ...which just tells us that we're doing a lot less AA queries, which is exactly the intention behind this. Of course the lit test failures indicate that regressions here are possible, even if they don't show up in practice.

IIRC those run-to-run stats changes are there always, and are therefore indicative of nondeterminism.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D89264/new/

https://reviews.llvm.org/D89264