[llvm] [LV] Ignore some costs when loop gets fully unrolled (PR #106699)

[LLVM Continuous Integration via llvm-commits]

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/14747

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

```
Step 5 (build-unified-tree) failure: build (failure)
...
18.877 [2660/29/4365] Building CXX object lib/Target/X86/MCTargetDesc/CMakeFiles/LLVMX86Desc.dir/X86WinCOFFStreamer.cpp.o
18.877 [2660/28/4366] Building CXX object lib/Target/X86/MCTargetDesc/CMakeFiles/LLVMX86Desc.dir/X86WinCOFFTargetStreamer.cpp.o
18.877 [2660/27/4367] Linking CXX static library lib/libLLVMX86Info.a
18.878 [2659/27/4368] Building CXX object lib/Target/X86/AsmParser/CMakeFiles/LLVMX86AsmParser.dir/X86AsmParser.cpp.o
18.878 [2659/26/4369] Building CXX object lib/Target/X86/MCTargetDesc/CMakeFiles/LLVMX86Desc.dir/X86AsmBackend.cpp.o
18.878 [2659/25/4370] Building CXX object lib/Target/X86/MCTargetDesc/CMakeFiles/LLVMX86Desc.dir/X86MCTargetDesc.cpp.o
18.879 [2658/25/4371] Building CXX object tools/llvm-exegesis/lib/X86/CMakeFiles/LLVMExegesisX86.dir/Target.cpp.o
18.889 [2658/24/4372] Linking CXX static library lib/libLLVMX86Disassembler.a
18.898 [2658/23/4373] Linking CXX static library lib/libLLVMX86Desc.a
18.936 [2658/22/4374] Building CXX object lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o
FAILED: lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.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/Vectorize -I/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Transforms/Vectorize -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/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o -MF lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o.d -o lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o -c /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:2699:49: error: reference to local binding 'IV' declared in enclosing function 'addFullyUnrolledInstructionsToIgnore'
               [&](const User *U) { return U == IV || U == Cmp; }))
                                                ^
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:2694:21: note: 'IV' declared here
  for (const auto &[IV, IndDesc] : IL) {
                    ^
1 error generated.
19.128 [2658/21/4375] Building CXX object lib/MC/MCParser/CMakeFiles/LLVMMCParser.dir/AsmParser.cpp.o
19.305 [2658/20/4376] Building AMDGPUGenCallingConv.inc...
19.628 [2658/19/4377] Building RISCVGenGlobalISel.inc...
19.758 [2658/18/4378] Building AMDGPUGenRegBankGICombiner.inc...
20.367 [2658/17/4379] Building AMDGPUGenPreLegalizeGICombiner.inc...
20.594 [2658/16/4380] Building AMDGPUGenPostLegalizeGICombiner.inc...
20.687 [2658/15/4381] Building AMDGPUGenDisassemblerTables.inc...
20.805 [2658/14/4382] Building AMDGPUGenSubtargetInfo.inc...
20.845 [2658/13/4383] Building RISCVGenDAGISel.inc...
21.192 [2658/12/4384] Building AMDGPUGenMCCodeEmitter.inc...
21.649 [2658/11/4385] Building AMDGPUGenSearchableTables.inc...
24.600 [2658/10/4386] Building CXX object lib/CodeGen/AsmPrinter/CMakeFiles/LLVMAsmPrinter.dir/AsmPrinter.cpp.o
25.787 [2658/9/4387] Building RISCVGenSubtargetInfo.inc...
26.724 [2658/8/4388] Building CXX object lib/LTO/CMakeFiles/LLVMLTO.dir/LTO.cpp.o
28.117 [2658/7/4389] Building AMDGPUGenAsmWriter.inc...
28.801 [2658/6/4390] Building AMDGPUGenGlobalISel.inc...
29.873 [2658/5/4391] Building AMDGPUGenDAGISel.inc...
29.995 [2658/4/4392] Building AMDGPUGenAsmMatcher.inc...
31.224 [2658/3/4393] Building AMDGPUGenInstrInfo.inc...
33.390 [2658/2/4394] Building AMDGPUGenRegisterInfo.inc...
33.637 [2658/1/4395] Building AMDGPUGenRegisterBank.inc...
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/106699