[llvm] [WIP][RISCV] Support for zvzip fasttrack proposal (PR #124140)

[Craig Topper via llvm-commits]

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@@ -805,6 +805,13 @@ def FeatureStdExtZvksc
 def FeatureStdExtZvksg
     : RISCVExtension<1, 0, "shorthand for 'Zvks' and 'Zvkg'",
                      [FeatureStdExtZvks, FeatureStdExtZvkg]>;
+
+def FeatureStdExtZvzip
+   :  RISCVExperimentalExtension<0, 1, "zip/unzip/zipeven/zipodd">;
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topperc wrote:

zip->vzip or add to match the instruction names and indicate vectorness. There's a scalar zip/unzip instruction in Zvkb.

https://github.com/llvm/llvm-project/pull/124140