[clang] [CIR] Add support for array constructors (PR #149142)

[Bruno Cardoso Lopes via cfe-commits]

================
@@ -2219,6 +2219,50 @@ def CIR_TrapOp : CIR_Op<"trap", [Terminator]> {
   let assemblyFormat = "attr-dict";
 }
 
+//===----------------------------------------------------------------------===//
+// ArrayCtor
+//===----------------------------------------------------------------------===//
+
+class CIR_ArrayInitDestroy<string mnemonic> : CIR_Op<mnemonic> {
+  let arguments = (ins
+    Arg<CIR_PtrToArray, "array address", [MemWrite, MemRead]>:$addr
+  );
+
+  let regions = (region SizedRegion<1>:$body);
+  let assemblyFormat = [{
+    `(` $addr `:` qualified(type($addr)) `)` $body attr-dict
+  }];
+
+  let builders = [
+    OpBuilder<(ins "mlir::Value":$addr,
+      "llvm::function_ref<void(mlir::OpBuilder &, mlir::Location)>":$regionBuilder), [{
+        assert(regionBuilder && "builder callback expected");
+        mlir::OpBuilder::InsertionGuard guard($_builder);
+        mlir::Region *r = $_state.addRegion();
+        $_state.addOperands(ValueRange{addr});
+        $_builder.createBlock(r);
+        regionBuilder($_builder, $_state.location);
+    }]>
+  ];
+}
+
+def CIR_ArrayCtor : CIR_ArrayInitDestroy<"array.ctor"> {
+  let summary = "Initialize array elements with C++ constructors";
+  let description = [{
+    Initialize each array element using the same C++ constructor. This
+    operation has one region, with one single block. The block has an
+    incoming argument for the current array index to initialize.
+
+    ```mlir
+    cir.array.ctor(%0 : !cir.ptr<!cir.array<!rec_S x 42>>) {
+      ^bb0(%arg0: !cir.ptr<!rec_S>):
+        cir.call @_ZN1SC1Ev(%arg0) : (!cir.ptr<!rec_S>) -> ()
----------------
bcardosolopes wrote:

`_ZN1SC1Ev` -> `some_ctor` would be more clear for the non-initiated 

https://github.com/llvm/llvm-project/pull/149142