Update clang to 18.1.2 release

[kraj]

Brings these changes

• 26a1d6601d72 [X86] Add missing subvector_subreg_lowering for BF16 (#83720)
• 0bf7ff1028fb [C++20] [Moduls] Avoid computing odr hash for functions from comparing constraint expression
• a2c93b34dfdf [RISCV] Fix mgather -> riscv.masked.strided.load combine not extending indices (#82506)
• a9d4ed71707d [RISCV] Adjust test case to show wrong stride. NFC
• 42f511c95c6f [RISCV] Add test case for miscompile in gather -> strided load combine. NFC
• 53ea0de61dcd [TSan] Fix atomicrmw xchg with pointer and floats (#85228)
• fd9f1faf8fcb [AVR] Remove earlyclobber from LDDRdPtrQ (#85277)
• 2d35ba4a8577 Revert "release/18.x: [openmp] __kmp_x86_cpuid fix for i386/PIC builds. (#846…"
• df20f2fc9998 [PowerPC] Update chain uses when emitting lxsizx (#84892)
• c09f6f6f4341 [llvm-shlib] Fix the version naming style of libLLVM for Windows (#85710)
• cba6ebf0d0ab [llvm-shlib] Fix libLLVM-18 symlink on mingw (#85554)
• bcf98bd84199 llvm-shlib: Fix libLLVM-${MAJOR}.so symlink on MacOS (#85163)
• b1f1effacf32 [WebAssembly] Change the default linker for wasm32-wasip2 (#84569)
• ecc22d27e5b8 workflows: Fix baseline version for llvm abi checks (#85166)
• 7fd9979eb9cf [InstCombine] Drop UB-implying attrs/metadata after speculating an instruction (#85542)
• edbe7fa5fef9 [lld][LoongArch] Fix handleUleb128
• b95ea2e51bdf [lld][test] Fix sanitizer buildbot failure
• 2f640ad26d17 Remove support for EXPORTAS in def files to maintain ABI compatibility for COFFShortExport
• 207ecd684cc6 [Arm64EC] Copy import descriptors to the EC Map (#84834)
• 79bc8b32c6ed [llvm-lib][Object] Add support for EC importlib symbols. (#81059)
• 76e1800f3565 [llvm-lib][llvm-dlltool][Object] Add support for EXPORTAS name types. (#78772)
• 77e1992e89d3 [llvm-readobj][Object][COFF] Print COFF import library symbol export name. (#78769)
• 3a06861272d8 [libc++] Use clang-tidy version that matches the compiler we use in the CI (#85305)
• 0c1dcd675291 [clangd] [HeuristicResolver] Protect against infinite recursion on DependentNameTypes (#83542)
• a649e0a6e80f [clang][modules] giving the _stddef headers their own modules can cause redeclaration errors with -fbuiltin-headers-in-system-modules (#84127)
• 12a3bf351575 workflows: Add workaround for lld failures on MacOS (#85021) (#85110)
• 9b3edb592deb release/18.x: [openmp] __kmp_x86_cpuid fix for i386/PIC builds. (#84626) (#85053)
• 600f7f2ba28f [clangd] Add clangd 18 release notes (#84436)
• bb83f055091c [runtimes] Prefer -fvisibility-global-new-delete=force-hidden (#84917)
• 122ba9f10070 [ELF] Eliminate symbols demoted due to /DISCARD/ discarded sections (#85167)
• 33c6b2027698 SystemZ release notes for 18.x. (#84560)
• 8c6015db5912 [X86][Inline] Skip inline asm in inlining target feature check (#83820)
• 38cf35dee880 [Inline] Add test for #67054 (NFC)
• c7eb919d2cbe [ValueTracking] Treat phi as underlying obj when not decomposing further (#84339)
• b01c3dcf2eb5 [LAA] Add test case for #82665.
• 159969b3880b [Release] Install compiler-rt builtins during Phase 1 on AIX (#81485)
• 7b61ddefc28a [ArgPromotion] Remove incorrect TranspBlocks set for loads. (#84835)
• 25a989ce8bf3 [ArgPromotion] Add test case for #84807.
• 2fc8bea42f99 [LLD] [COFF] Set the right alignment for DelayDirectoryChunk (#84697)
• fcc33dca02d1 [X86] combineAndShuffleNot - ensure the type is legal before create X86ISD::ANDNP target nodes
• 39e3ba8a383e [DSE] Remove malloc from EarliestEscapeInfo before removing. (#84157)
• 3f8711fc5e01 [InstCombine] Fix miscompilation in PR83947 (#83993)
• 9b9aee16d4dc [Clang][LoongArch] Fix wrong return value type of __iocsrrd_h (#84100)
• a9ba36c7e7d7 [Clang][LoongArch] Precommit test for fix wrong return value type of __iocsrrd_h. NFC
• d77c5c3830d9 [LoongArch] Make sure that the LoongArchISD::BSTRINS node uses the correct MSB value (#84454)
• 1de8ea75d9b3 [analyzer] Fix crash on dereference invalid return value of getAdjustedParameterIndex() (#83585)
• c14bf0a13d42 [libc++] Enable availability based on the compiler instead of __has_extension (#84065)
• 55193c2ba53f [InstCombine] Handle scalable splat in getFlippedStrictnessPredicateAndConstant
• 78859f118a6b [lld][LoongArch] Support the RLARCH{ADD,SUB}_ULEB128 relocation types (#81133)
• d8352e93c1c8 [Clang] [Sema] Handle placeholders in '.*' expressions (#83103)
• eb9bc02b06cb [RISCV] Fix crash when unrolling loop containing vector instructions (#83384)
• c3721c1dcff5 [ELF] Internalize enum
• c14879562f46 Unbreak *tf builtins for hexfloat (#82208)
• 89d543227a32 [AArch64] Skip over shadow space for ARM64EC entry thunk variadic calls (#80994)
• 42c599ab365b [AArch64] Fix generated types for ARM64EC variadic entry thunk targets (#80595)
• d7a9810f9c14 [AArch64] Fix variadic tail-calls on ARM64EC (#79774)
• ea6c457b8dd2 [LoongArch] Override LoongArchTargetLowering::getExtendForAtomicCmpSwapArg (#83656)
• 69d9b15fe872 [TableGen] Fix wrong codegen of BothFusionPredicateWithMCInstPredicate (#83990)
• a91b9bd9c750 [OpenMP] fix endianness dependent definitions in OMP headers for MSVC (#84540)
• 7cb67530d2e9 ReleaseNotes for LLVM binary utilities (#83751)
• 94d8f150ed8b [InstCombine] Fix infinite loop in select equivalence fold (#84036)
• 4c36ecbe0e16 [InstCombine] Fix shift calculation in InstCombineCasts (#84027)
• e90bfdb4ddce [test] Make two sanitize-coverage tests pass with glibc 2.39+
• bf45c3a07918 [DSE] Delay deleting non-memory-defs until end of DSE. (#83411)
• 16ab0812d201 [clang][fat-lto-objects] Make module flags match non-FatLTO pipelines (#83159)
• 267d9b1a74c4 Allow .alt_entry symbols to pass the .cfi nesting check (#82268)
• 340ba4588c80 MIPS: fix emitDirectiveCpsetup on N32 (#80534)
• 439e6f81e772 [libc++][modules] Fixes naming inconsistency. (#83036)
• 2ad8fbdbca06 Bump version to 18.1.2 (#84655)

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