[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 `lldb-x86_64-debian` running on `lldb-x86_64-debian` while building `llvm` at step 4 "build".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/162/builds/12190

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

```
Step 4 (build) failure: build (failure)
...
4.321 [57/12/69] Linking CXX executable bin/llvm-debuginfo-analyzer
4.584 [57/11/70] Linking CXX shared module lib/CheckerDependencyHandlingAnalyzerPlugin.so
4.616 [57/10/71] Linking CXX executable bin/diagtool
4.634 [57/9/72] Linking CXX shared module lib/CheckerOptionHandlingAnalyzerPlugin.so
4.728 [57/8/73] Linking CXX shared module lib/SampleAnalyzerPlugin.so
5.061 [57/7/74] Linking CXX executable bin/clang-diff
5.126 [57/6/75] Linking CXX executable bin/clang-installapi
5.137 [57/5/76] Linking CXX executable bin/clang-refactor
5.139 [57/4/77] Linking CXX executable bin/arcmt-test
6.246 [57/3/78] Building CXX object lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o
FAILED: lib/Transforms/Vectorize/CMakeFiles/LLVMVectorize.dir/LoopVectorize.cpp.o 
/usr/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/worker/2.0.1/lldb-x86_64-debian/build/lib/Transforms/Vectorize -I/home/worker/2.0.1/lldb-x86_64-debian/llvm-project/llvm/lib/Transforms/Vectorize -I/home/worker/2.0.1/lldb-x86_64-debian/build/include -I/home/worker/2.0.1/lldb-x86_64-debian/llvm-project/llvm/include -fPIC -fno-semantic-interposition -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 /home/worker/2.0.1/lldb-x86_64-debian/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
/home/worker/2.0.1/lldb-x86_64-debian/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; }))
                                                ^
/home/worker/2.0.1/lldb-x86_64-debian/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:2694:21: note: 'IV' declared here
  for (const auto &[IV, IndDesc] : IL) {
                    ^
1 error generated.
11.513 [57/2/79] Building CXX object lib/CodeGen/AsmPrinter/CMakeFiles/LLVMAsmPrinter.dir/AsmPrinter.cpp.o
12.648 [57/1/80] Building CXX object lib/LTO/CMakeFiles/LLVMLTO.dir/LTO.cpp.o
ninja: build stopped: subcommand failed.

```

</details>

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