[clang] [llvm] [FMV] Add alias for FEAT_RDM and change priorities according to ACLE. (PR #79316)

[Pavel Iliin via cfe-commits]

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@@ -114,6 +121,10 @@ const AArch64::ArchInfo *AArch64::parseArch(StringRef Arch) {
 }
 
 std::optional<AArch64::ExtensionInfo> AArch64::parseArchExtension(StringRef ArchExt) {
+  // Resolve aliases first.
+  ArchExt = resolveExtAlias(ArchExt);
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ilinpv wrote:

Seems resolving aliases here expands "rdma" alias beyond FMV.

https://github.com/llvm/llvm-project/pull/79316