[llvm] [VPlan] Allow cleanup of dead ExpandSCEVs (PR #208952)

[via llvm-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Windows-->
# :window: Windows x64 Test Results

* 138413 tests passed
* 3520 tests skipped
* 1 test failed

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

### LLVM
<details>
<summary>LLVM.Transforms/PhaseOrdering/AArch64/indvars-vectorization.ll</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
c:\_work\llvm-project\llvm-project\build\bin\opt.exe -passes="default<O3>" -S -o - C:\_work\llvm-project\llvm-project\llvm\test\Transforms\PhaseOrdering\AArch64\indvars-vectorization.ll | c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe C:\_work\llvm-project\llvm-project\llvm\test\Transforms\PhaseOrdering\AArch64\indvars-vectorization.ll
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\opt.exe' '-passes=default<O3>' -S -o - 'C:\_work\llvm-project\llvm-project\llvm\test\Transforms\PhaseOrdering\AArch64\indvars-vectorization.ll'
# note: command had no output on stdout or stderr
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe' 'C:\_work\llvm-project\llvm-project\llvm\test\Transforms\PhaseOrdering\AArch64\indvars-vectorization.ll'
# .---command stderr------------
# | C:\_work\llvm-project\llvm-project\llvm\test\Transforms\PhaseOrdering\AArch64\indvars-vectorization.ll:69:10: error: CHECK: expected string not found in input
# | ; CHECK: for.body.preheader13:
# |          ^
# | <stdin>:71:59: note: scanning from here
# |  br i1 %cmp.n, label %for.end, label %for.body.preheader10
# |                                                           ^
# | <stdin>:73:1: note: possible intended match here
# | for.body.preheader10: ; preds = %vector.memcheck, %for.body.preheader, %middle.block
# | ^
# | 
# | Input file: <stdin>
# | Check file: C:\_work\llvm-project\llvm-project\llvm\test\Transforms\PhaseOrdering\AArch64\indvars-vectorization.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             .
# |             .
# |             .
# |            66:  %22 = icmp eq i64 %index.next, %n.vec 
# |            67:  br i1 %22, label %middle.block, label %vector.body, !llvm.loop !5 
# |            68:  
# |            69: middle.block: ; preds = %vector.body 
# |            70:  %cmp.n = icmp eq i64 %4, %n.vec 
# |            71:  br i1 %cmp.n, label %for.end, label %for.body.preheader10 
# | check:69'0                                                              {   search range start (exclusive)
# | check:69'1                                                                  error: no match found in search range
# |            72:  
# |            73: for.body.preheader10: ; preds = %vector.memcheck, %for.body.preheader, %middle.block 
# | check:69'2     ?                                                                                      possible intended match
# |            74:  %indvars.iv.ph = phi i64 [ %0, %vector.memcheck ], [ %0, %for.body.preheader ], [ %14, %middle.block ] 
# |            75:  br label %for.body 
# |            76:  
# |            77: for.body: ; preds = %for.body.preheader10, %for.body 
# |            78:  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ %indvars.iv.ph, %for.body.preheader10 ] 
# |             .
# |             .
# |             .
# |           103: !4 = distinct !{!4, !2} 
# |           104: !5 = distinct !{!5, !6, !7, !8} 
# |           105: !6 = !{!"llvm.loop.mustprogress"} 
# |           106: !7 = !{!"llvm.loop.isvectorized", i32 1} 
# |           107: !8 = !{!"llvm.loop.unroll.runtime.disable"} 
# |           108: !9 = distinct !{!9, !6, !7} 
# | check:69'3                                 } search range end (exclusive)
# | >>>>>>
# `-----------------------------
# 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/208952