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

Fri Feb 21 17:17:32 PST 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-x86_64-debian-dylib` running on `gribozavr4` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/60/builds/20165

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

```
Step 5 (build-unified-tree) failure: build (failure)
...
28.346 [4815/96/2243] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBInterfaceAnchors.cpp.o
28.370 [4814/96/2244] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbol.cpp.o
28.383 [4813/96/2245] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolAnnotation.cpp.o
28.396 [4812/96/2246] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolBlock.cpp.o
28.412 [4811/96/2247] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolCompiland.cpp.o
28.414 [4810/96/2248] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolCompilandDetails.cpp.o
28.422 [4809/96/2249] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolCompilandEnv.cpp.o
28.424 [4808/96/2250] Building AArch64GenInstrInfo.inc...
28.424 [4807/96/2251] Building X86GenSubtargetInfo.inc...
28.434 [4806/96/2252] Building CXX object lib/Transforms/Utils/CMakeFiles/LLVMTransformUtils.dir/SimplifyCFG.cpp.o
FAILED: lib/Transforms/Utils/CMakeFiles/LLVMTransformUtils.dir/SimplifyCFG.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes /usr/bin/ccache /usr/bin/clang++ -DGTEST_HAS_RTTI=0 -DLLVM_EXPORTS -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/b/1/llvm-x86_64-debian-dylib/build/lib/Transforms/Utils -I/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Transforms/Utils -I/b/1/llvm-x86_64-debian-dylib/build/include -I/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/include -fPIC -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -std=c++17 -MD -MT lib/Transforms/Utils/CMakeFiles/LLVMTransformUtils.dir/SimplifyCFG.cpp.o -MF lib/Transforms/Utils/CMakeFiles/LLVMTransformUtils.dir/SimplifyCFG.cpp.o.d -o lib/Transforms/Utils/CMakeFiles/LLVMTransformUtils.dir/SimplifyCFG.cpp.o -c /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Transforms/Utils/SimplifyCFG.cpp:2503:3: error: reference to 'LockstepReverseIterator' is ambiguous
  LockstepReverseIterator<true> LRI(UnconditionalPreds);
  ^
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/include/llvm/Transforms/Utils/LockstepReverseIterator.h:41:7: note: candidate found by name lookup is 'llvm::LockstepReverseIterator'
class LockstepReverseIterator
      ^
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Transforms/Utils/SimplifyCFG.cpp:1787:7: note: candidate found by name lookup is '(anonymous namespace)::LockstepReverseIterator'
class LockstepReverseIterator {
      ^
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Transforms/Utils/SimplifyCFG.cpp:2533:44: error: reference to 'LockstepReverseIterator' is ambiguous
    auto ProfitableToSinkInstruction = [&](LockstepReverseIterator<true> &LRI) {
                                           ^
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/include/llvm/Transforms/Utils/LockstepReverseIterator.h:41:7: note: candidate found by name lookup is 'llvm::LockstepReverseIterator'
class LockstepReverseIterator
      ^
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Transforms/Utils/SimplifyCFG.cpp:1787:7: note: candidate found by name lookup is '(anonymous namespace)::LockstepReverseIterator'
class LockstepReverseIterator {
      ^
2 errors generated.
28.435 [4806/95/2253] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolCustom.cpp.o
28.435 [4806/94/2254] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolData.cpp.o
28.435 [4806/93/2255] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolExe.cpp.o
28.435 [4806/92/2256] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolFunc.cpp.o
28.436 [4806/91/2257] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolFuncDebugEnd.cpp.o
28.436 [4806/90/2258] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolFuncDebugStart.cpp.o
28.436 [4806/89/2259] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolLabel.cpp.o
28.436 [4806/88/2260] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolPublicSymbol.cpp.o
28.437 [4806/87/2261] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolThunk.cpp.o
28.437 [4806/86/2262] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolTypeArray.cpp.o
28.437 [4806/85/2263] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolTypeBaseClass.cpp.o
28.437 [4806/84/2264] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolTypeBuiltin.cpp.o
28.438 [4806/83/2265] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolTypeCustom.cpp.o
28.438 [4806/82/2266] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolTypeDimension.cpp.o
28.438 [4806/81/2267] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolTypeEnum.cpp.o
28.438 [4806/80/2268] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolTypeFriend.cpp.o
28.439 [4806/79/2269] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolTypeFunctionArg.cpp.o
28.439 [4806/78/2270] Building CXX object lib/DebugInfo/PDB/CMakeFiles/LLVMDebugInfoPDB.dir/PDBSymbolTypeFunctionSig.cpp.o

```

</details>

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