[ImportVerilog] Add support for buf primitive (#10227)

Author: TaoBi22

lib/Conversion/ImportVerilog/Structure.cpp

@@ -1888,6 +1888,9 @@ LogicalResult Context::convertNOutputPrimitive(
       llvm::StringSwitch<std::function<Value()>>(prim.primitiveType.name)
           .Case("not",
                 ([&] { return moore::NotOp::create(builder, loc, inputVal); }))
+          .Case("buf", ([&] {
+                  return moore::BoolCastOp::create(builder, loc, inputVal);
+                }))
           .Default([&] {
             mlir::emitError(loc)
                 << "unsupported primitive `" << primName << "`";

test/Conversion/ImportVerilog/primitives.sv

@@ -158,3 +158,15 @@ module multi_not_prim;
     logic A, Q0, Q1;
     not n (Q0, Q1, A);
 endmodule
+
+// CHECK-LABEL: moore.module @buf_prim()
+// CHECK: [[A:%.+]] = moore.variable : <l1>
+// CHECK: [[Q:%.+]] = moore.variable : <l1>
+// CHECK: [[RD_A:%.+]] = moore.read [[A]] : <l1>
+// CHECK: [[NOT:%.+]] = moore.bool_cast [[RD_A]] : l1
+// CHECK: moore.assign [[Q]], [[NOT]] : l1
+
+module buf_prim;
+    logic A, Q;
+    buf n (Q, A);
+endmodule