[PATCH] D91435: [AMDGPU] Split edge to make si_if dominate end_cf

Fri Dec 18 12:57:01 PST 2020

arsenm added a comment.

In D91435#2463824 <https://reviews.llvm.org/D91435#2463824>, @alex-t wrote:

> In D91435#2461075 <https://reviews.llvm.org/D91435#2461075>, @arsenm wrote:
>
>> Needs a testcase for the second broken case
>
> I cannot create a relevant testcase. The CFG pattern that triggers the bug only appears in IR compiled with clang.

It must be possible, and cannot only appear through clang

> The reason is that RegionInfo cannot distinguish regions and treat the whole function as one region. As a result CFG structurizer does nothing with it.
> When compiling by LLC structurizer does his job and produces good CFG that does not trigger the bug.
> MIR test is problematic as well.  We need DivergenceAnalysis to make SIAnnotateCF work correctly.  DA requires all the Target information to be able to determine if the target is divergent.

This is an IR test, MIR does not come into this.

> I still have no idea how to run  tti, divergence and si-annotate-control-flow separately and provide the target information to the "-run-pass'"

You shouldn't be trying to use -run-pass/llc, this is an opt test with the relevant passes and then an end to end ISA run line

Repository:
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https://reviews.llvm.org/D91435