[flang][hlfir] Handle scalar to array in hlfir.assign codegen.

[jeanPerier]

Summary

The scalar must be placed in memory before creating descriptors and
calling the runtime assignment API.

[clementval]

LGTM

flang/lib/Optimizer/HLFIR/Transforms/ConvertToFIR.cpp

matchAndRewrite(hlfir::AssignOp assignOp,
     auto [rhsExv, rhsCleanUp] =
         hlfir::translateToExtendedValue(loc, builder, rhs);
     auto [lhsExv, lhsCleanUp] =
         hlfir::translateToExtendedValue(loc, builder, lhs);
     assert(!lhsCleanUp && !rhsCleanUp &&
            "variable to fir::ExtendedValue must not require cleanup");
 
     if (lhs.isArray()) {
+      const bool rhsIsValue = fir::isa_trivial(fir::getBase(rhsExv).getType());
+      if (rhsIsValue) {
+        // createBox can only be called for fir::ExtendedValue that are
+        // already in memory. Place the integer/real/complex/logical scalar
+        // in memory (convert to the LHS type so that i1 are allocated in
+        // a proper Fortran logical storage).
+        mlir::Type lhsValueType = lhs.getFortranElementType();
+        mlir::Value rhsVal =
+            builder.createConvert(loc, lhsValueType, fir::getBase(rhsExv));
+        mlir::Value temp = builder.create<fir::AllocaOp>(loc, lhsValueType);
+        builder.create<fir::StoreOp>(loc, rhsVal, temp);
+        rhsExv = temp;
+      }
+
       // Use the runtime for simplicity. An optimization pass will be added to
       // inline array assignment when profitable.
       auto to = fir::getBase(builder.createBox(loc, lhsExv));
       auto from = fir::getBase(builder.createBox(loc, rhsExv));
       bool cleanUpTemp = false;
-      if (mayAlias(rhs, lhs))
+      if (!rhsIsValue && mayAlias(rhs, lhs))
         std::tie(from, cleanUpTemp) = genTempFromSourceBox(loc, builder, from);
 
       auto toMutableBox = builder.createTemporary(loc, to.getType());
       // As per 10.2.1.2 point 1 (1) polymorphic variables must be allocatable.
       // It is assumed here that they have been reallocated with the dynamic
       // type and that the mutableBox will not be modified.
       builder.create<fir::StoreOp>(loc, to, toMutableBox);
       fir::runtime::genAssign(builder, loc, toMutableBox, from);

flang/test/HLFIR/assign-codegen.fir

 // CHECK:  %[[VAL_21:.*]] = fir.call @_FortranAAssign(%[[VAL_18]], %[[VAL_19]], %{{.*}}, %{{.*}}) : (!fir.ref<!fir.box<none>>, !fir.box<none>, !fir.ref<i8>, i32) -> none
 // CHECK:  %[[VAL_22:.*]] = fir.load %[[VAL_3]] : !fir.ref<!fir.box<!fir.heap<!fir.array<100xi32>>>>
 // CHECK:  fir.store %[[VAL_5]] to %[[VAL_2]] : !fir.ref<!fir.box<!fir.array<?xi32>>>
 // CHECK:  %[[VAL_26:.*]] = fir.convert %[[VAL_2]] : (!fir.ref<!fir.box<!fir.array<?xi32>>>) -> !fir.ref<!fir.box<none>>
 // CHECK:  %[[VAL_27:.*]] = fir.convert %[[VAL_22]] : (!fir.box<!fir.heap<!fir.array<100xi32>>>) -> !fir.box<none>
 // CHECK:  %[[VAL_29:.*]] = fir.call @_FortranAAssign(%[[VAL_26]], %[[VAL_27]], %{{.*}}, %{{.*}}) : (!fir.ref<!fir.box<none>>, !fir.box<none>, !fir.ref<i8>, i32) -> none
 // CHECK:  %[[VAL_30:.*]] = fir.box_addr %[[VAL_22]] : (!fir.box<!fir.heap<!fir.array<100xi32>>>) -> !fir.heap<!fir.array<100xi32>>
 // CHECK:  fir.freemem %[[VAL_30]] : !fir.heap<!fir.array<100xi32>>
+
+
+func.func @test_scalar_to_array(%lhs: !fir.box<!fir.array<?xi32>>, %rhs: i32) {
+  hlfir.assign %rhs to %lhs : i32, !fir.box<!fir.array<?xi32>>
+  return
+}
+// CHECK-LABEL:   func.func @test_scalar_to_array(
+// CHECK-SAME:    %[[VAL_0:.*]]: !fir.box<!fir.array<?xi32>>,
+// CHECK-SAME:    %[[VAL_1:.*]]: i32) {
+// CHECK:  %[[VAL_2:.*]] = fir.alloca !fir.box<!fir.array<?xi32>>
+// CHECK:  %[[VAL_5:.*]] = fir.alloca i32
+// CHECK:  fir.store %[[VAL_1]] to %[[VAL_5]] : !fir.ref<i32>
+// CHECK:  %[[VAL_6:.*]] = fir.embox %[[VAL_5]] : (!fir.ref<i32>) -> !fir.box<i32>
+// CHECK:  fir.store %[[VAL_0]] to %[[VAL_2]] : !fir.ref<!fir.box<!fir.array<?xi32>>>
+// CHECK:  %[[VAL_10:.*]] = fir.convert %[[VAL_2]] : (!fir.ref<!fir.box<!fir.array<?xi32>>>) -> !fir.ref<!fir.box<none>>
+// CHECK:  %[[VAL_11:.*]] = fir.convert %[[VAL_6]] : (!fir.box<i32>) -> !fir.box<none>
+// CHECK:  %[[VAL_13:.*]] = fir.call @_FortranAAssign(%[[VAL_10]], %[[VAL_11]]
+
+
+func.func @test_i1_scalar_to_array(%lhs: !fir.box<!fir.array<?x!fir.logical<4>>>, %rhs: i1) {
+  hlfir.assign %rhs to %lhs : i1, !fir.box<!fir.array<?x!fir.logical<4>>>
+  return
+}
+// CHECK-LABEL:   func.func @test_i1_scalar_to_array(
+// CHECK:  %[[VAL_5:.*]] = fir.convert %{{.*}} : (i1) -> !fir.logical<4>
+// CHECK:  %[[VAL_6:.*]] = fir.alloca !fir.logical<4>
+// CHECK:  %[[VAL_7:.*]] = fir.embox %[[VAL_6]] : (!fir.ref<!fir.logical<4>>) -> !fir.box<!fir.logical<4>>
+// CHECK:  %[[VAL_12:.*]] = fir.convert %[[VAL_7]] : (!fir.box<!fir.logical<4>>) -> !fir.box<none>
+// CHECK:  %[[VAL_14:.*]] = fir.call @_FortranAAssign(%{{.*}}, %[[VAL_12]]