[clang] [compiler-rt] [llvm] [X86] Sync multiversion features with libgcc and refactor internal feature tables (PR #168750)

[via llvm-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

The build failed before running any tests. Click on a failure below to see the details.

<details>
<summary>lib/TargetParser/CMakeFiles/LLVMTargetParser.dir/X86TargetParser.cpp.o</summary>

```
FAILED: lib/TargetParser/CMakeFiles/LLVMTargetParser.dir/X86TargetParser.cpp.o
sccache /opt/llvm/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GLIBCXX_USE_CXX11_ABI=1 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/gha/actions-runner/_work/llvm-project/llvm-project/build/lib/TargetParser -I/home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/TargetParser -I/home/gha/actions-runner/_work/llvm-project/llvm-project/build/include -I/home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/include -gmlt -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror -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 -Wno-pass-failed -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -MD -MT lib/TargetParser/CMakeFiles/LLVMTargetParser.dir/X86TargetParser.cpp.o -MF lib/TargetParser/CMakeFiles/LLVMTargetParser.dir/X86TargetParser.cpp.o.d -o lib/TargetParser/CMakeFiles/LLVMTargetParser.dir/X86TargetParser.cpp.o -c /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/TargetParser/X86TargetParser.cpp
/home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/TargetParser/X86TargetParser.cpp:547:25: error: unused variable 'ImpliedFeaturesDUMMYFEATURE1' [-Werror,-Wunused-const-variable]
547 | constexpr FeatureBitset ImpliedFeaturesDUMMYFEATURE1 = {};
|                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/TargetParser/X86TargetParser.cpp:548:25: error: unused variable 'ImpliedFeaturesDUMMYFEATURE2' [-Werror,-Wunused-const-variable]
548 | constexpr FeatureBitset ImpliedFeaturesDUMMYFEATURE2 = {};
|                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/TargetParser/X86TargetParser.cpp:549:25: error: unused variable 'ImpliedFeaturesDUMMYFEATURE3' [-Werror,-Wunused-const-variable]
549 | constexpr FeatureBitset ImpliedFeaturesDUMMYFEATURE3 = {};
|                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/lib/TargetParser/X86TargetParser.cpp:550:25: error: unused variable 'ImpliedFeaturesDUMMYFEATURE4' [-Werror,-Wunused-const-variable]
550 | constexpr FeatureBitset ImpliedFeaturesDUMMYFEATURE4 = {};
|                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
4 errors generated.
```
</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/168750