[clang] [llvm] [RISCV][MC] Support experimental Zilx extension (PR #209419)

[Pengcheng Wang via cfe-commits]

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@@ -204,6 +204,13 @@ def FeatureZilsdWordAlign
     : SubtargetFeature<"zilsd-word-align", "AllowZilsdWordAlign", "true",
                        "Allow 4-byte alignment for Zilsd LD/SD instructions">;
 
+def FeatureStdExtZilx
+    : RISCVExperimentalExtension<0, 1, "Index Load for Integer">;
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wangpc-pp wrote:

I can change the name (since I am the author 😄). I need to figure out which one is the best.

https://github.com/llvm/llvm-project/pull/209419