[llvm] [Utils] Consolidate `LockstepReverseIterator` into own header (NFC) (PR #116657)

Fri Feb 21 13:17:30 PST 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-win-fast` running on `as-builder-3` while building `llvm` at step 6 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/2/builds/17612

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (build-unified-tree) failure: build (failure)
...
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[2635/4123] Building CXX object lib\AsmParser\CMakeFiles\LLVMAsmParser.dir\LLParser.cpp.obj
[2636/4123] Building CXX object lib\Passes\CMakeFiles\LLVMPasses.dir\CodeGenPassBuilder.cpp.obj
[2637/4123] Building CXX object lib\Passes\CMakeFiles\LLVMPasses.dir\StandardInstrumentations.cpp.obj
[2638/4123] Building CXX object lib\Transforms\Utils\CMakeFiles\LLVMTransformUtils.dir\SimplifyCFG.cpp.obj
FAILED: lib/Transforms/Utils/CMakeFiles/LLVMTransformUtils.dir/SimplifyCFG.cpp.obj 
C:\ninja\ccache.exe C:\PROGRA~1\MICROS~2\2022\COMMUN~1\VC\Tools\MSVC\1438~1.331\bin\Hostx64\x64\cl.exe  /nologo /TP -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_HAS_EXCEPTIONS=0 -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -IC:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\build\lib\Transforms\Utils -IC:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\lib\Transforms\Utils -IC:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\build\include -IC:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\include /DWIN32 /D_WINDOWS   /Zc:inline /Zc:preprocessor /Zc:__cplusplus /Oi /bigobj /permissive- /W4 -wd4141 -wd4146 -wd4244 -wd4267 -wd4291 -wd4351 -wd4456 -wd4457 -wd4458 -wd4459 -wd4503 -wd4624 -wd4722 -wd4100 -wd4127 -wd4512 -wd4505 -wd4610 -wd4510 -wd4702 -wd4245 -wd4706 -wd4310 -wd4701 -wd4703 -wd4389 -wd4611 -wd4805 -wd4204 -wd4577 -wd4091 -wd4592 -wd4319 -wd4709 -wd5105 -wd4324 -wd4251 -wd4275 -w14062 -we4238 /Gw /O2 /Ob2 /DNDEBUG -MD  /EHs-c- /GR- -std:c++17 /showIncludes /Folib\Transforms\Utils\CMakeFiles\LLVMTransformUtils.dir\SimplifyCFG.cpp.obj /Fdlib\Transforms\Utils\CMakeFiles\LLVMTransformUtils.dir\LLVMTransformUtils.pdb /FS -c C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\lib\Transforms\Utils\SimplifyCFG.cpp
C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\lib\Transforms\Utils\SimplifyCFG.cpp(2503): error C2872: 'LockstepReverseIterator': ambiguous symbol
C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\include\llvm/Transforms/Utils/LockstepReverseIterator.h(42): note: could be 'llvm::LockstepReverseIterator'
C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\lib\Transforms\Utils\SimplifyCFG.cpp(1787): note: or       '`anonymous-namespace'::LockstepReverseIterator'
C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\lib\Transforms\Utils\SimplifyCFG.cpp(2533): error C2872: 'LockstepReverseIterator': ambiguous symbol
C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\include\llvm/Transforms/Utils/LockstepReverseIterator.h(42): note: could be 'llvm::LockstepReverseIterator'
C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\lib\Transforms\Utils\SimplifyCFG.cpp(1787): note: or       '`anonymous-namespace'::LockstepReverseIterator'
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```

</details>

https://github.com/llvm/llvm-project/pull/116657