[llvm] Reapply "[VPlan] Remove manual region removal when simplifying for VF and UF. (#181252)" (PR #188589)

[via llvm-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

* 171775 tests passed
* 3076 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### LLVM
<details>
<summary>LLVM.Transforms/PhaseOrdering/ARM/arm_var_q31.ll</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/opt < /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/ARM/arm_var_q31.ll -passes="default<O3>" -S | /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/FileCheck /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/ARM/arm_var_q31.ll
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/opt '-passes=default<O3>' -S
# note: command had no output on stdout or stderr
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/FileCheck /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/ARM/arm_var_q31.ll
# .---command stderr------------
# | /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/ARM/arm_var_q31.ll:77:10: error: CHECK: expected string not found in input
# | ; CHECK: while.body.preheader67:
# |          ^
# | <stdin>:76:72: note: scanning from here
# |  br i1 %cmp.n, label %while.end.loopexit, label %while.body.preheader63
# |                                                                        ^
# | <stdin>:78:1: note: possible intended match here
# | while.body.preheader63: ; preds = %while.body.preheader, %middle.block
# | ^
# | 
# | Input file: <stdin>
# | Check file: /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/Transforms/PhaseOrdering/ARM/arm_var_q31.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             .
# |             .
# |             .
# |            71:  %34 = icmp eq i32 %index.next, %n.vec 
# |            72:  br i1 %34, label %middle.block, label %vector.body, !llvm.loop !8 
# |            73:  
# |            74: middle.block: ; preds = %vector.body 
# |            75:  %cmp.n = icmp eq i32 %shr, %n.vec 
# |            76:  br i1 %cmp.n, label %while.end.loopexit, label %while.body.preheader63 
# | check:77'0                                                                            X error: no match found
# |            77:  
# | check:77'0     ~
# |            78: while.body.preheader63: ; preds = %while.body.preheader, %middle.block 
# | check:77'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# | check:77'1     ?                                                                       possible intended match
# |            79:  %sumOfSquares.043.ph = phi i64 [ 0, %while.body.preheader ], [ %25, %middle.block ] 
# | check:77'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |            80:  %pSrc.addr.042.ph = phi ptr [ %pSrc, %while.body.preheader ], [ %1, %middle.block ] 
# | check:77'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |            81:  %blkCnt.041.ph = phi i32 [ %shr, %while.body.preheader ], [ %2, %middle.block ] 
# | check:77'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |            82:  %sum.040.ph = phi i64 [ 0, %while.body.preheader ], [ %33, %middle.block ] 
# | check:77'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |            83:  br label %while.body 
# | check:77'0     ~~~~~~~~~~~~~~~~~~~~~~
# |             .
# |             .
# |             .
# | >>>>>>
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/188589