[clang] [CIR][AArch64] Support BF16/FP16 NEON types and lower vdup lane builtins (PR #187460)

[Andrzej Warzyński via cfe-commits]

================
@@ -191,7 +204,7 @@ static mlir::Value emitCommonNeonBuiltinExpr(
 
   // The value of allowBFloatArgsAndRet is true for AArch64, but it should
   // come from ABI info.
-  const bool allowBFloatArgsAndRet = false;
+  const bool allowBFloatArgsAndRet = cgf.getTarget().hasFastHalfType();
----------------
banach-space wrote:

```suggestion
  // TODO(cir): Use ABInfo to extract this information
  const bool allowBFloatArgsAndRet = cgf.getTarget().hasFastHalfType();
```

https://github.com/llvm/llvm-project/pull/187460