[clang] [clang][X86] Support __attribute__((model("small"/"large"))) (PR #124834)

[Arthur Eubanks via cfe-commits]

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@@ -62,6 +62,10 @@ def CodeModelDocs : Documentation {
   let Content = [{
 The ``model`` attribute allows overriding the translation unit's
 code model (specified by ``-mcmodel``) for a specific global variable.
+
+On LoongArch, allowed values are "normal", "medium", "extreme".
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aeubanks wrote:

I've added some description at least on the x86-64 side of things

https://github.com/llvm/llvm-project/pull/124834