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

Fri Dec 18 12:54:17 PST 2020

alex-t added a comment.

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.
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.
Same time we need to avoid all the passes in between including structurizer. So, MIR test is going to be quite tricky.
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'"

Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D91435