[clang] [llvm] [RISC-V][MC] Introduce initial support for RVY (CHERI) (PR #199771)

[Craig Topper via cfe-commits]

================
@@ -809,6 +819,17 @@ struct RISCVOperand final : public MCParsedAsmOperand {
     return IsConstantImm && isInt<N>(fixImmediateForRV32(Imm, isRV64Expr()));
   }
 
+  bool isYBNDSWImm() const {
+    if (!isExpr())
+      return false;
+
+    int64_t Imm;
+    bool IsConstantImm = evaluateConstantExpr(getExpr(), Imm);
+    if (!IsConstantImm)
+      return false;
+    return RISCV::isValidYBNDSWImm(Imm);
----------------
topperc wrote:

```suggestion
    return IsConstantImm && RISCV::isValidYBNDSWImm(Imm);
```

https://github.com/llvm/llvm-project/pull/199771