[clang] [CIR] Upstream minimal builtin function call support (PR #142981)

[Andy Kaylor via cfe-commits]

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@@ -1858,6 +1858,40 @@ def FuncOp : CIR_Op<"func", [
   let hasVerifier = 1;
 }
 
+//===----------------------------------------------------------------------===//
+// LLVMIntrinsicCallOp
+//===----------------------------------------------------------------------===//
+
+def LLVMIntrinsicCallOp : CIR_Op<"llvm.intrinsic"> {
+  let summary = "Call to llvm intrinsic functions that is not defined in CIR";
+  let description = [{
+    The `cir.llvm.intrinsic` operation represents a call-like expression which has
+    a return type and arguments that map directly to an llvm intrinsic.
+    It only records its own name (`intrinsic_name`).
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andykaylor wrote:

This last sentence is a bit cryptic. Does it mean that it only records the base intrinsic name without polymorphic modifiers?

https://github.com/llvm/llvm-project/pull/142981