[PATCH] D94019: Switching Clang UniqueInternalLinkageNamesPass scheduling to using the LLVM one with newpm.

Mon Jan 4 15:56:38 PST 2021

dblaikie added a comment.

In D94019#2478206 <https://reviews.llvm.org/D94019#2478206>, @hoy wrote:

> In D94019#2478048 <https://reviews.llvm.org/D94019#2478048>, @dblaikie wrote:
>
>> In D94019#2478047 <https://reviews.llvm.org/D94019#2478047>, @hoy wrote:
>>
>>> In D94019#2478045 <https://reviews.llvm.org/D94019#2478045>, @dblaikie wrote:
>>>
>>>> Please add a clang test for this.
>>>
>>> There is the original clang test `unique-internal-linkage-names.cpp` that still works with the change here. What kind of new test would you like?
>>
>> Something that tests this change (something that would fail before this patch is applied, and passes afterwards - demonstrating the change in behavior). Either something like the LLVM test, testing the pass sequence, or something with very simple IR (something that can robustly demonstrate the change in optimization behavior due to this patch and will be resilient to as many other changes to LLVM as possible (ie: something that captures the essence of this change)).
>
> I'm not sure how to test this change if LLVM is treated as a black box to clang. This patch doesn't seem to change anything fundamental from the Clang point of view. My understanding is that the previous placement of the unique name pass in the pipeline didn't seem particularly important to Clang, therefore we ended up just testing the whole Clang output. If that's the case, I don't think we need to test the pass order here with this change.

My understanding was that the change in pass ordering has some observable change in the total behavior of LLVM? So an end-to-end test could be used here (I tend towards preferring the checking the pass ordering, but understand @aeubanks contrasting position)  - that's what I was trying to describe in the "or something with very simple IR (... )" part of my suggestion. If the change in pass order can be observed in terms of different final IR, that's what an end-to-end Clang test could validate.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D94019/new/

https://reviews.llvm.org/D94019