[clang] [llvm] [RISCV] Support spacemit vsmtvdotii externsions (PR #202533)

[Luke Lau via cfe-commits]

================
@@ -553,6 +558,44 @@ inline static bool isValidRoundingMode(unsigned Mode) {
 }
 } // namespace RISCVFPRndMode
 
+namespace XSMTVTypeMode {
+enum SMTVTypeMode {
+  // Define the different SMT VType modes here
+  SMT_I4 = 2,
+  SMT_I8 = 3,
+  Invalid
+};
+
+inline static StringRef SMTVTypeModeToString(SMTVTypeMode TypeMode) {
+  switch (TypeMode) {
+  default:
+    llvm_unreachable("Unknown VType's mode of SpacemiT Integer Matrix");
----------------
lukel97 wrote:

```suggestion
    llvm_unreachable("Unknown VType mode of SpacemiT Integer Matrix");
```

https://github.com/llvm/llvm-project/pull/202533