[llvm] [clang] [clang-tools-extra] [X86] Emit Warnings for frontend options to enable knl/knm specific ISAs. (PR #75580)

[Freddy Ye via cfe-commits]

================
@@ -933,6 +933,9 @@ X86 Support
 - Support ISA of ``AVX10.1``.
 - ``-march=pantherlake`` and ``-march=clearwaterforest`` are now supported.
 - Added ABI handling for ``__float128`` to match with GCC.
+- Emit Warnings for clang options to enable knl/knm. From next version
+  (LLVM 19), all-end supports on knl/knm and other Xeon Phi targets will be
+  removed.
----------------
FreddyLeaf wrote:

addressed fef605e95d2ec8f5a3c2a339e014cb700d5b8a27

https://github.com/llvm/llvm-project/pull/75580