[llvm] [clang] [RISCV][MC] Add experimental support of Zaamo and Zalrsc (PR #78970)

[Craig Topper via cfe-commits]

================
@@ -1307,6 +1309,13 @@
 // CHECK-ZVKT-EXT: __riscv_zvkt 1000000{{$}}
 
 // Experimental extensions
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN: -march=rv32i_zaamo0p1 -x c -E -dM %s \
----------------
topperc wrote:

It's not working. It failed the automated testing

```
clang: error: invalid arch name 'rv32i_zaamo0p1', unsupported version number 0.1 for experimental extension 'zaamo' (this compiler supports 0.2)
```

https://github.com/llvm/llvm-project/pull/78970