[flang-commits] [flang] [flang][hlfir] Support box in user defined assignments (PR #77578)

[via flang-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-flang-fir-hlfir

Author: None (jeanPerier)

<details>
<summary>Changes</summary>

When dealing with overlaps in user defined assignments, some entities with descriptors (fir.box) may be saved without descriptors. The current code was replacing the original box entity with the "raw" copy with a simple cast instead of creating a box for the copy. This patch ensures a fir.embox is emitted instead.

---
Full diff: https://github.com/llvm/llvm-project/pull/77578.diff


2 Files Affected:

- (modified) flang/lib/Optimizer/HLFIR/Transforms/LowerHLFIROrderedAssignments.cpp (+8) 
- (modified) flang/test/HLFIR/order_assignments/user-defined-assignment.fir (+23) 


``````````diff
diff --git a/flang/lib/Optimizer/HLFIR/Transforms/LowerHLFIROrderedAssignments.cpp b/flang/lib/Optimizer/HLFIR/Transforms/LowerHLFIROrderedAssignments.cpp
index c4aee7d39e4a3c..84101353a740a0 100644
--- a/flang/lib/Optimizer/HLFIR/Transforms/LowerHLFIROrderedAssignments.cpp
+++ b/flang/lib/Optimizer/HLFIR/Transforms/LowerHLFIROrderedAssignments.cpp
@@ -421,6 +421,14 @@ convertToMoldType(mlir::Location loc, fir::FirOpBuilder &builder,
   }
   // Variable to Variable mismatch (e.g., fir.heap<T> vs fir.ref<T>), or value
   // to Value mismatch (e.g. i1 vs fir.logical<4>).
+  if (mlir::isa<fir::BaseBoxType>(mold.getType()) &&
+      !mlir::isa<fir::BaseBoxType>(input.getType())) {
+    // An entity may have have been saved without descriptor while the original
+    // value had a descriptor (e.g., it was not contiguous).
+    auto emboxed = hlfir::convertToBox(loc, builder, input, mold.getType());
+    assert(!emboxed.second && "temp should already be in memory");
+    input = hlfir::Entity{fir::getBase(emboxed.first)};
+  }
   return hlfir::Entity{builder.createConvert(loc, mold.getType(), input)};
 }
 
diff --git a/flang/test/HLFIR/order_assignments/user-defined-assignment.fir b/flang/test/HLFIR/order_assignments/user-defined-assignment.fir
index 521288d0cfa12b..61836b8bcc57eb 100644
--- a/flang/test/HLFIR/order_assignments/user-defined-assignment.fir
+++ b/flang/test/HLFIR/order_assignments/user-defined-assignment.fir
@@ -180,3 +180,26 @@ func.func @test_scalar_forall_overlap(%i: !fir.ref<!fir.array<10xi32>>) {
 // CHECK:    fir.call @logical_value_to_numeric(%[[VAL_32]], %[[VAL_33]]) : (!fir.ref<i32>, !fir.logical<4>) -> ()
 // CHECK:  }
 // CHECK:  fir.freemem %[[VAL_15]] : !fir.heap<!fir.array<?xi1>>
+
+func.func @test_saved_scalar_box(%arg0: !fir.box<!fir.type<sometype>>, %arg1: !fir.class<!fir.type<sometype>>) {
+  hlfir.region_assign {
+    hlfir.yield %arg0 : !fir.box<!fir.type<sometype>>
+  } to {
+    hlfir.yield %arg1 : !fir.class<!fir.type<sometype>>
+  } user_defined_assign  (%arg2: !fir.box<!fir.type<sometype>>) to (%arg3: !fir.class<!fir.type<sometype>>) {
+    fir.call @user_assign_box(%arg3, %arg2) : (!fir.class<!fir.type<sometype>>, !fir.box<!fir.type<sometype>>) -> ()
+  }
+  return
+}
+func.func private @user_assign_box(!fir.class<!fir.type<sometype>>, !fir.box<!fir.type<sometype>>) -> ()
+
+// CHECK-LABEL:   func.func @test_saved_scalar_box(
+// CHECK-SAME:                    %[[VAL_0:.*]]: !fir.box<!fir.type<sometype>>,
+// CHECK-SAME:                    %[[VAL_1:.*]]: !fir.class<!fir.type<sometype>>) {
+// CHECK:           %[[VAL_2:.*]] = hlfir.as_expr %[[VAL_0]] : (!fir.box<!fir.type<sometype>>) -> !hlfir.expr<!fir.type<sometype>>
+// CHECK:           %[[VAL_3:.*]]:3 = hlfir.associate %[[VAL_2]]
+// CHECK:           %[[VAL_4:.*]] = fir.embox %[[VAL_3]]#1 : (!fir.ref<!fir.type<sometype>>) -> !fir.box<!fir.type<sometype>>
+// CHECK:           fir.call @user_assign_box(%[[VAL_1]], %[[VAL_4]]) : (!fir.class<!fir.type<sometype>>, !fir.box<!fir.type<sometype>>) -> ()
+// CHECK:           hlfir.end_associate %[[VAL_3]]#1, %[[VAL_3]]#2 : !fir.ref<!fir.type<sometype>>, i1
+// CHECK:           return
+// CHECK:         }

``````````

</details>


https://github.com/llvm/llvm-project/pull/77578