[clang] [llvm] [RISCV][VLS] Support RISCV VLS calling convention (PR #100346)

[Craig Topper via llvm-commits]

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@@ -1333,6 +1333,15 @@ def Experimental
    : SubtargetFeature<"experimental", "HasExperimental",
                       "true", "Experimental intrinsics">;
 
+def FeatureABIVLen32B
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topperc wrote:

Can we put this in the frontend's CodeGenOpts instead of using feature flags? I don't really want to burn 12 bits in SubtargetFeatures on something the backend doesn't need.

I think you can use a CC1Option with MarshallingInfo in Options.td to define a command line flag for the cc1 process to get it into CodeGenOpts.

https://github.com/llvm/llvm-project/pull/100346