[llvm] [AMDGPU] Add half vector support for table-driven libcall optimization (PR #178638)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-aarch64-darwin` running on `doug-worker-4` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/37720

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang-Unit :: ./AllClangUnitTests/19/50' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/tools/clang/unittests/./AllClangUnitTests-Clang-Unit-30311-19-50.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=50 GTEST_SHARD_INDEX=19 /Volumes/RAMDisk/buildbot-root/aarch64-darwin/build/tools/clang/unittests/./AllClangUnitTests
--

Note: This is test shard 20 of 50.
[==========] Running 511 tests from 108 test suites.
[----------] Global test environment set-up.
[----------] 1 test from MinimizeSourceToDependencyDirectivesTest
[ RUN      ] MinimizeSourceToDependencyDirectivesTest.DefineNoWhitespace
[       OK ] MinimizeSourceToDependencyDirectivesTest.DefineNoWhitespace (0 ms)
[----------] 1 test from MinimizeSourceToDependencyDirectivesTest (0 ms total)

[----------] 1 test from HeaderSearchTest
[ RUN      ] HeaderSearchTest.Dots
[       OK ] HeaderSearchTest.Dots (0 ms)
[----------] 1 test from HeaderSearchTest (0 ms total)

[----------] 1 test from ModuleDeclStateTest
[ RUN      ] ModuleDeclStateTest.ModuleWithGMF
[       OK ] ModuleDeclStateTest.ModuleWithGMF (0 ms)
[----------] 1 test from ModuleDeclStateTest (0 ms total)

[----------] 1 test from ParseHLSLRootSignatureTest
[ RUN      ] ParseHLSLRootSignatureTest.InvalidRepeatedMandatoryRCParameterTest
[       OK ] ParseHLSLRootSignatureTest.InvalidRepeatedMandatoryRCParameterTest (0 ms)
[----------] 1 test from ParseHLSLRootSignatureTest (0 ms total)

[----------] 1 test from ToolChainTest
[ RUN      ] ToolChainTest.GetTargetAndMode
/Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/unittests/Driver/ToolChainTest.cpp:447: Skipped


[  SKIPPED ] ToolChainTest.GetTargetAndMode (0 ms)
[----------] 1 test from ToolChainTest (0 ms total)

[----------] 1 test from DependencyScanningFilesystem
[ RUN      ] DependencyScanningFilesystem.OpenFileAndGetBufferRepeatedly
[       OK ] DependencyScanningFilesystem.OpenFileAndGetBufferRepeatedly (0 ms)
[----------] 1 test from DependencyScanningFilesystem (0 ms total)

[----------] 2 tests from ExprMutationAnalyzerTest
[ RUN      ] ExprMutationAnalyzerTest.ByNonConstRefArgument
input.cc:1:23: warning: function 'f()::A::A' has internal linkage but is not defined [-Wundefined-internal]
    1 | void f() { struct A { A(int&); }; int x; A y(x); }
      |                       ^
input.cc:1:44: note: used here
    1 | void f() { struct A { A(int&); }; int x; A y(x); }
      |                                            ^
...

```

</details>

https://github.com/llvm/llvm-project/pull/178638