[SCFToCalyx] Add test for multiple return values

Author: mortbopet

test/Conversion/SCFToCalyx/convert_simple.mlir

@@ -38,3 +38,39 @@ module {
     return %2 : i32
   }
 }
+
+// -----
+
+// Test multiple return values.
+
+// CHECK:      module  {
+// CHECK-NEXT:   calyx.program "main"  {
+// CHECK-NEXT:     calyx.component @main(%in0: i32, %in1: i32, %clk: i1 {clk}, %reset: i1 {reset}, %go: i1 {go}) -> (%out0: i32, %out1: i32, %done: i1 {done}) {
+// CHECK-NEXT:       %true = hw.constant true
+// CHECK-NEXT:       %ret_arg1_reg.in, %ret_arg1_reg.write_en, %ret_arg1_reg.clk, %ret_arg1_reg.reset, %ret_arg1_reg.out, %ret_arg1_reg.done = calyx.register "ret_arg1_reg" : i32, i1, i1, i1, i32, i1
+// CHECK-NEXT:       %ret_arg0_reg.in, %ret_arg0_reg.write_en, %ret_arg0_reg.clk, %ret_arg0_reg.reset, %ret_arg0_reg.out, %ret_arg0_reg.done = calyx.register "ret_arg0_reg" : i32, i1, i1, i1, i32, i1
+// CHECK-NEXT:       calyx.wires  {
+// CHECK-NEXT:         calyx.assign %out1 = %ret_arg1_reg.out : i32
+// CHECK-NEXT:         calyx.assign %out0 = %ret_arg0_reg.out : i32
+// CHECK-NEXT:         calyx.group @ret_assign_0  {
+// CHECK-NEXT:           calyx.assign %ret_arg0_reg.in = %in0 : i32
+// CHECK-NEXT:           calyx.assign %ret_arg0_reg.write_en = %true : i1
+// CHECK-NEXT:           calyx.assign %ret_arg1_reg.in = %in1 : i32
+// CHECK-NEXT:           calyx.assign %ret_arg1_reg.write_en = %true : i1
+// CHECK-NEXT:           %0 = comb.and %ret_arg0_reg.done, %ret_arg1_reg.done : i1
+// CHECK-NEXT:           calyx.group_done %true, %0 ? : i1
+// CHECK-NEXT:         }
+// CHECK-NEXT:       }
+// CHECK-NEXT:       calyx.control  {
+// CHECK-NEXT:         calyx.seq  {
+// CHECK-NEXT:           calyx.enable @ret_assign_0
+// CHECK-NEXT:         }
+// CHECK-NEXT:       }
+// CHECK-NEXT:     }
+// CHECK-NEXT:   }
+// CHECK-NEXT: }
+module {
+  func @main(%a0 : i32, %a1 : i32) -> (i32, i32) {
+    return %a0, %a1 : i32, i32
+  }
+}