[flang] Fixed branch-to-default generation for select_type.

[vzakhari]

Summary

When the default case requires block arguments, they have to be passed
through the cf.br - this piece was missing.

[clementval]

Thanks for fixing this. LGTM

[vzakhari]

In D149484#4306650, @clementval wrote:

Thanks for fixing this. LGTM

Thank you for the prompt review!

flang/lib/Optimizer/Transforms/PolymorphicOpConversion.cpp

mlir::LogicalResult SelectTypeConv::matchAndRewrite(
   assert(orderedTypeGuards.size() == typeGuardNum &&
          "ordered type guard size doesn't match number of type guards");
 
   for (unsigned idx : orderedTypeGuards) {
     auto *dest = selectType.getSuccessor(idx);
     std::optional<mlir::ValueRange> destOps =
         selectType.getSuccessorOperands(operands, idx);
     if (typeGuards[idx].dyn_cast<mlir::UnitAttr>())
-      rewriter.replaceOpWithNewOp<mlir::cf::BranchOp>(selectType, dest);
+      rewriter.replaceOpWithNewOp<mlir::cf::BranchOp>(
+          selectType, dest, destOps.value_or(mlir::ValueRange{}));
     else if (mlir::failed(genTypeLadderStep(loc, selector, typeGuards[idx],
                                             dest, destOps, mod, rewriter,
                                             kindMap)))
       return mlir::failure();
   }
   return mlir::success();
 }
 

flang/test/Lower/select-type-2.fir

+// RUN: fir-opt --fir-polymorphic-op %s | FileCheck %s
+
+// Test that cf.br for the default select case passes the blocks argument
+// as expected.
+
+// Original code:
+//subroutine test()
+//  interface
+//     function fstar()
+//       class(*),pointer :: fstar
+//     end function fstar
+//     subroutine foo(x)
+//       class(*) :: x
+//     end subroutine foo
+//  end interface
+//
+//  select type(y=>fstar())
+//  type is (integer)
+//    y = 777
+//  class default
+//     call foo(y)
+//     stop 'fail type'
+//  end select
+//
+//  select type(y=>fstar())
+//  type is (integer)
+//    y = 23
+//  class default
+//     call foo(y)
+//     stop 'fail type'
+//  end select
+//end subroutine test
+
+// CHECK-LABEL:   func.func @_QPtest() {
+// CHECK:           %[[VAL_0:.*]] = arith.constant 23 : i32
+// CHECK:           %[[VAL_1:.*]] = arith.constant false
+// CHECK:           %[[VAL_2:.*]] = arith.constant 9 : index
+// CHECK:           %[[VAL_3:.*]] = arith.constant 777 : i32
+// CHECK:           %[[VAL_4:.*]] = fir.alloca !fir.class<!fir.ptr<none>> {bindc_name = ".result"}
+// CHECK:           %[[VAL_5:.*]] = fir.alloca !fir.class<!fir.ptr<none>> {bindc_name = ".result"}
+// CHECK:           %[[VAL_6:.*]] = fir.call @_QPfstar() fastmath<contract> : () -> !fir.class<!fir.ptr<none>>
+// CHECK:           fir.save_result %[[VAL_6]] to %[[VAL_5]] : !fir.class<!fir.ptr<none>>, !fir.ref<!fir.class<!fir.ptr<none>>>
+// CHECK:           %[[VAL_7:.*]] = fir.load %[[VAL_5]] : !fir.ref<!fir.class<!fir.ptr<none>>>
+// CHECK:           %[[VAL_8:.*]] = arith.constant 9 : i8
+// CHECK:           %[[VAL_9:.*]] = fir.box_typecode %[[VAL_7]] : (!fir.class<!fir.ptr<none>>) -> i8
+// CHECK:           %[[VAL_10:.*]] = arith.cmpi eq, %[[VAL_9]], %[[VAL_8]] : i8
+// CHECK:           cf.cond_br %[[VAL_10]], ^bb2, ^bb1
+// CHECK:         ^bb1:
+// CHECK:           cf.br ^bb3(%[[VAL_7]] : !fir.class<!fir.ptr<none>>)
+// CHECK:         ^bb2:
+// CHECK:           %[[VAL_11:.*]] = fir.box_addr %[[VAL_7]] : (!fir.class<!fir.ptr<none>>) -> !fir.ptr<i32>
+// CHECK:           fir.store %[[VAL_3]] to %[[VAL_11]] : !fir.ptr<i32>
+// CHECK:           %[[VAL_12:.*]] = fir.call @_QPfstar() fastmath<contract> : () -> !fir.class<!fir.ptr<none>>
+// CHECK:           fir.save_result %[[VAL_12]] to %[[VAL_4]] : !fir.class<!fir.ptr<none>>, !fir.ref<!fir.class<!fir.ptr<none>>>
+// CHECK:           %[[VAL_13:.*]] = fir.load %[[VAL_4]] : !fir.ref<!fir.class<!fir.ptr<none>>>
+// CHECK:           %[[VAL_14:.*]] = arith.constant 9 : i8
+// CHECK:           %[[VAL_15:.*]] = fir.box_typecode %[[VAL_13]] : (!fir.class<!fir.ptr<none>>) -> i8
+// CHECK:           %[[VAL_16:.*]] = arith.cmpi eq, %[[VAL_15]], %[[VAL_14]] : i8
+// CHECK:           cf.cond_br %[[VAL_16]], ^bb5, ^bb4
+// CHECK:         ^bb3(%[[VAL_17:.*]]: !fir.class<!fir.ptr<none>>):
+// CHECK:           %[[VAL_18:.*]] = fir.rebox %[[VAL_17]] : (!fir.class<!fir.ptr<none>>) -> !fir.class<none>
+// CHECK:           fir.call @_QPfoo(%[[VAL_18]]) fastmath<contract> : (!fir.class<none>) -> ()
+// CHECK:           %[[VAL_19:.*]] = fir.address_of(@_QQcl.6661696C2074797065) : !fir.ref<!fir.char<1,9>>
+// CHECK:           %[[VAL_20:.*]] = fir.convert %[[VAL_19]] : (!fir.ref<!fir.char<1,9>>) -> !fir.ref<i8>
+// CHECK:           %[[VAL_21:.*]] = fir.convert %[[VAL_2]] : (index) -> i64
+// CHECK:           %[[VAL_22:.*]] = fir.call @_FortranAStopStatementText(%[[VAL_20]], %[[VAL_21]], %[[VAL_1]], %[[VAL_1]]) fastmath<contract> : (!fir.ref<i8>, i64, i1, i1) -> none
+// CHECK:           fir.unreachable
+// CHECK:         ^bb4:
+// CHECK:           cf.br ^bb3(%[[VAL_13]] : !fir.class<!fir.ptr<none>>)
+// CHECK:         ^bb5:
+// CHECK:           %[[VAL_23:.*]] = fir.box_addr %[[VAL_13]] : (!fir.class<!fir.ptr<none>>) -> !fir.ptr<i32>
+// CHECK:           fir.store %[[VAL_0]] to %[[VAL_23]] : !fir.ptr<i32>
+// CHECK:           return
+// CHECK:         }
+func.func @_QPtest() {
+  %c23_i32 = arith.constant 23 : i32
+  %false = arith.constant false
+  %c9 = arith.constant 9 : index
+  %c777_i32 = arith.constant 777 : i32
+  %0 = fir.alloca !fir.class<!fir.ptr<none>> {bindc_name = ".result"}
+  %1 = fir.alloca !fir.class<!fir.ptr<none>> {bindc_name = ".result"}
+  %2 = fir.call @_QPfstar() fastmath<contract> : () -> !fir.class<!fir.ptr<none>>
+  fir.save_result %2 to %1 : !fir.class<!fir.ptr<none>>, !fir.ref<!fir.class<!fir.ptr<none>>>
+  %3 = fir.load %1 : !fir.ref<!fir.class<!fir.ptr<none>>>
+  fir.select_type %3 : !fir.class<!fir.ptr<none>> [#fir.type_is<i32>, ^bb1, unit, ^bb2(%3 : !fir.class<!fir.ptr<none>>)]
+^bb1:  // pred: ^bb0
+  %4 = fir.box_addr %3 : (!fir.class<!fir.ptr<none>>) -> !fir.ptr<i32>
+  fir.store %c777_i32 to %4 : !fir.ptr<i32>
+  %5 = fir.call @_QPfstar() fastmath<contract> : () -> !fir.class<!fir.ptr<none>>
+  fir.save_result %5 to %0 : !fir.class<!fir.ptr<none>>, !fir.ref<!fir.class<!fir.ptr<none>>>
+  %6 = fir.load %0 : !fir.ref<!fir.class<!fir.ptr<none>>>
+  fir.select_type %6 : !fir.class<!fir.ptr<none>> [#fir.type_is<i32>, ^bb3, unit, ^bb2(%6 : !fir.class<!fir.ptr<none>>)]
+^bb2(%7: !fir.class<!fir.ptr<none>>):  // 2 preds: ^bb0, ^bb1
+  %8 = fir.rebox %7 : (!fir.class<!fir.ptr<none>>) -> !fir.class<none>
+  fir.call @_QPfoo(%8) fastmath<contract> : (!fir.class<none>) -> ()
+  %9 = fir.address_of(@_QQcl.6661696C2074797065) : !fir.ref<!fir.char<1,9>>
+  %10 = fir.convert %9 : (!fir.ref<!fir.char<1,9>>) -> !fir.ref<i8>
+  %11 = fir.convert %c9 : (index) -> i64
+  %12 = fir.call @_FortranAStopStatementText(%10, %11, %false, %false) fastmath<contract> : (!fir.ref<i8>, i64, i1, i1) -> none
+  fir.unreachable
+^bb3:  // pred: ^bb1
+  %13 = fir.box_addr %6 : (!fir.class<!fir.ptr<none>>) -> !fir.ptr<i32>
+  fir.store %c23_i32 to %13 : !fir.ptr<i32>
+  return
+}