[clang] [CIR][NFC] Improve the output for missing builtin calls (PR #163884)

[Andy Kaylor via cfe-commits]

https://github.com/andykaylor created https://github.com/llvm/llvm-project/pull/163884

This improves the diagnostic emitted when `errorNYI` is called for missing builtin calls so that the builtin being called is displayed in the diagnostic.

>From 9bc4a68abb6315b6a3b1b8b0dbc2ae2167fcab92 Mon Sep 17 00:00:00 2001
From: Andy Kaylor <akaylor at nvidia.com>
Date: Thu, 16 Oct 2025 15:45:39 -0700
Subject: [PATCH] [CIR][NFC] Improve the output for missing builtin calls

This improves the diagnostic emitted when `errorNYI` is called for
missing builtin calls so that the builtin being called is displayed
in the diagnostic.
---
 clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
index 4cfa91e09efb4..ea31871806bd7 100644
--- a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
@@ -463,7 +463,9 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
     return emitLibraryCall(*this, fd, e,
                            cgm.getBuiltinLibFunction(fd, builtinID));
 
-  cgm.errorNYI(e->getSourceRange(), "unimplemented builtin call");
+  cgm.errorNYI(e->getSourceRange(),
+               std::string("unimplemented builtin call: ") +
+                   getContext().BuiltinInfo.getName(builtinID));
   return getUndefRValue(e->getType());
 }