[all-commits] [llvm/llvm-project] fd86d6: [JumpThreading] Add a test that duplicates insts o...

[Juneyoung Lee via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: fd86d67b82830f1365e1e25fd138832b475bc1e7
      https://github.com/llvm/llvm-project/commit/fd86d67b82830f1365e1e25fd138832b475bc1e7
  Author: Juneyoung Lee <aqjune at gmail.com>
  Date:   2020-08-06 (Thu, 06 Aug 2020)

  Changed paths:
    A llvm/test/Transforms/JumpThreading/phi-copy-to-pred.ll

  Log Message:
  -----------
  [JumpThreading] Add a test that duplicates insts of a basic block with cond br to preds; NFC


  Commit: 9f717d7b941fbc42bef017b84c4dd0f65ce06e7a
      https://github.com/llvm/llvm-project/commit/9f717d7b941fbc42bef017b84c4dd0f65ce06e7a
  Author: Juneyoung Lee <aqjune at gmail.com>
  Date:   2020-08-06 (Thu, 06 Aug 2020)

  Changed paths:
    M llvm/lib/Transforms/Scalar/JumpThreading.cpp
    M llvm/test/Transforms/JumpThreading/phi-copy-to-pred.ll

  Log Message:
  -----------
  [JumpThreading] Allow duplicating a basic block into preds when its branch condition is freeze(phi)

This is the last JumpThreading patch for getting the performance numbers shown at
https://reviews.llvm.org/D84940#2184653 .

This patch makes ProcessBlock call ProcessBranchOnPHI when the branch condition
is freeze(phi) as well (originally it calls the function when the condition is
phi only).

Since what ProcessBranchOnPHI does is to duplicate the basic block into
predecessors if profitable, it is still valid when the condition is freeze(phi)
too.

```
    p = phi [a, pred1] [b, pred2]
    p.fr = freeze p
    br p.fr, ...
=>
  pred1:
    p.fr = freeze a
    br p.fr, ...
  pred2:
    p.fr2 = freeze b
    br p.fr2, ...
```

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D85029


Compare: https://github.com/llvm/llvm-project/compare/3af4039876a1...9f717d7b941f