[clang] [CIR] Add emitBuiltinWithOneOverloadedType helper (PR #199518)

[Andy Kaylor via cfe-commits]

================
@@ -1625,6 +1625,25 @@ class CIRGenFunction : public CIRGenTypeCache {
 
   void instantiateIndirectGotoBlock();
 
+  /// Emit a simple LLVM intrinsic that takes N scalar arguments and whose
+  /// return type matches the type of the first argument. The intrinsic name is
+  /// used verbatim; any overload mangling (e.g. `.f32`, `.p1`) must be baked
+  /// into \p Name by the caller.
+  template <uint32_t N>
+  [[maybe_unused]] RValue
+  emitBuiltinWithOneOverloadedType(const CallExpr *E, llvm::StringRef Name) {
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andykaylor wrote:

```suggestion
  emitBuiltinWithOneOverloadedType(const CallExpr *e, llvm::StringRef intrinName) {
```
Use CIR naming style, but also, because this function exists in both CIR and classic codegen, I think it's important to make it clear that the second parameter here is the intrinsic name, and not the value name (as it is in classic codegen).

https://github.com/llvm/llvm-project/pull/199518