[all-commits] [llvm/llvm-project] cb7c01: [NFC][SimplifyCFG] Add test for failed assertion

[Roman Lebedev via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: cb7c01889ec21accc12b2c19a395b521e3b959a3
      https://github.com/llvm/llvm-project/commit/cb7c01889ec21accc12b2c19a395b521e3b959a3
  Author: Roman Lebedev <lebedev.ri at gmail.com>
  Date:   2021-08-13 (Fri, 13 Aug 2021)

  Changed paths:
    A llvm/test/Transforms/SimplifyCFG/tautological-conditional-branch.ll

  Log Message:
  -----------
  [NFC][SimplifyCFG] Add test for failed assertion

This would trigger an assertion that was added in rGf30a7dff8a5b.
Need to fix that before relanding.

Reduced from https://reviews.llvm.org/rGf30a7dff8a5b#1019890


  Commit: 2702fb11484a6f5d99c712a0e92c221288955c56
      https://github.com/llvm/llvm-project/commit/2702fb11484a6f5d99c712a0e92c221288955c56
  Author: Roman Lebedev <lebedev.ri at gmail.com>
  Date:   2021-08-13 (Fri, 13 Aug 2021)

  Changed paths:
    M llvm/lib/Transforms/Utils/SimplifyCFG.cpp
    M llvm/test/Transforms/SimplifyCFG/tautological-conditional-branch.ll

  Log Message:
  -----------
  [SimplifyCFG] Restart if `removeUndefIntroducingPredecessor()` made changes

It might changed the condition of a branch into a constant,
so we should restart and constant-fold terminator,
instead of continuing with the tautological "conditional" branch.
This fixes the issue reported at https://reviews.llvm.org/rGf30a7dff8a5b32919951dcbf92e4a9d56c4679ff


  Commit: c46546bd521b7c3f98a1620c9227e80dc94a5a3c
      https://github.com/llvm/llvm-project/commit/c46546bd521b7c3f98a1620c9227e80dc94a5a3c
  Author: Roman Lebedev <lebedev.ri at gmail.com>
  Date:   2021-08-13 (Fri, 13 Aug 2021)

  Changed paths:
    M llvm/lib/Transforms/Utils/SimplifyCFG.cpp

  Log Message:
  -----------
  Reland "[NFCI][SimplifyCFG] simplifyCondBranch(): assert that branch is non-tautological""

The commit originally unearthed a problem, reported as
https://reviews.llvm.org/rGf30a7dff8a5b32919951dcbf92e4a9d56c4679ff#1019890
Now that the problem has been fixed, and the assertion no longer fires,
let's see if there are other cases it fires on.

This reverts commit 5c8c24d2decae4a76047777271d60411fc3316eb,
relanding commit f30a7dff8a5b32919951dcbf92e4a9d56c4679ff.


Compare: https://github.com/llvm/llvm-project/compare/8738c5b0fe0a...c46546bd521b