[clang] [llvm] [RISCV][VCIX] Add vcix_state to GNU inline assembly register set (PR #106914)

[Brandon Wu via cfe-commits]

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@@ -664,5 +664,9 @@ def FRM    : RISCVReg<0, "frm">;
 // Shadow Stack register
 def SSP    : RISCVReg<0, "ssp">;
 
-// Dummy VCIX state register
+// Dummy VCIX state register and its register class
 def VCIX_STATE : RISCVReg<0, "vcix_state">;
+def : RISCVRegisterClass<[XLenVT], 32, (add VCIX_STATE)> {
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4vtomat wrote:

In `getRegForInlineAsmConstraint` if there would be no value in `AssignedRegs` when calling `getRegistersForValue` for the `vcix_state` constraint, thus it would be deprecated when constructing selectionDAG.

https://github.com/llvm/llvm-project/pull/106914