[clang] [llvm] [X86] Add Support for X86 TLSDESC Relocations (PR #83136)

[Fangrui Song via cfe-commits]

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@@ -740,7 +740,8 @@ bool tools::isTLSDESCEnabled(const ToolChain &TC,
     SupportedArgument = V == "desc" || V == "trad";
     EnableTLSDESC = V == "desc";
   } else if (Triple.isX86()) {
-    SupportedArgument = V == "gnu";
+    SupportedArgument = V == "gnu" || V == "gnu2";
+    EnableTLSDESC = V == "gnu2";
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MaskRay wrote:

If GCC is happy to accept `trad` and `desc` aliases, then we can accept the aliases; otherwise, I do not want to introduce another way to express the same thing.

https://github.com/llvm/llvm-project/pull/83136