Index: flang/lib/Lower/Bridge.cpp
===================================================================
--- flang/lib/Lower/Bridge.cpp
+++ flang/lib/Lower/Bridge.cpp
@@ -2983,6 +2983,42 @@
     }
   }
 
+  /// Given converted LHS and RHS of the assignment, generate
+  /// explicit type conversion for implicit Logical<->Integer
+  /// conversion. Return Value representing the converted RHS,
+  /// if the implicit Logical<->Integer is detected, otherwise,
+  /// return nullptr. The caller is responsible for inserting
+  /// DestroyOp in case the returned value has hlfir::ExprType.
+  mlir::Value
+  genImplicitLogicalConvert(const Fortran::evaluate::Assignment &assign,
+                            hlfir::Entity lhs, hlfir::Entity rhs) {
+    mlir::Type fromTy = rhs.getFortranElementType();
+    mlir::Type toTy = lhs.getFortranElementType();
+    if (fromTy == toTy)
+      return nullptr;
+
+    if (!fromTy.isa<mlir::IntegerType, fir::LogicalType>())
+      return nullptr;
+    if (!toTy.isa<mlir::IntegerType, fir::LogicalType>())
+      return nullptr;
+
+    mlir::Location loc = toLocation();
+    auto &builder = getFirOpBuilder();
+    if (assign.rhs.Rank() == 0)
+      return builder.createConvert(loc, toTy, rhs);
+
+    mlir::Value shape = hlfir::genShape(loc, builder, rhs);
+    auto genKernel =
+        [&rhs, &toTy](mlir::Location loc, fir::FirOpBuilder &builder,
+                      mlir::ValueRange oneBasedIndices) -> hlfir::Entity {
+      auto elementPtr = hlfir::getElementAt(loc, builder, rhs, oneBasedIndices);
+      auto val = hlfir::loadTrivialScalar(loc, builder, elementPtr);
+      return hlfir::EntityWithAttributes{builder.createConvert(loc, toTy, val)};
+    };
+    return hlfir::genElementalOp(loc, builder, toTy, shape, /*typeParams=*/{},
+                                 genKernel);
+  }
+
   /// Shared for both assignments and pointer assignments.
   void genAssignment(const Fortran::evaluate::Assignment &assign) {
     mlir::Location loc = toLocation();
@@ -3020,9 +3056,24 @@
                   // Dereference pointer LHS: the target is being assigned to.
                   lhs = hlfir::derefPointersAndAllocatables(loc, builder, lhs);
                 }
+
+                // Logical<->Integer assignments are allowed as an extension,
+                // but there is no explicit Convert expression for the RHS.
+                // Recognize the type mismatch here and insert explicit
+                // scalar convert or ElementalOp for array assignment.
+                mlir::Value logicalConvert =
+                    genImplicitLogicalConvert(assign, lhs, rhs);
+                if (logicalConvert)
+                  rhs = hlfir::EntityWithAttributes{logicalConvert};
+
                 builder.create<hlfir::AssignOp>(
                     loc, rhs, lhs, isWholeAllocatableAssignment,
                     keepLhsLengthInAllocatableAssignment);
+
+                // Mark the end of life range of the ElementalOp's result.
+                if (logicalConvert &&
+                    logicalConvert.getType().isa<hlfir::ExprType>())
+                  builder.create<hlfir::DestroyOp>(loc, rhs);
               },
               // [2] User defined assignment. If the context is a scalar
               // expression then call the procedure.
Index: flang/lib/Optimizer/HLFIR/Transforms/ConvertToFIR.cpp
===================================================================
--- flang/lib/Optimizer/HLFIR/Transforms/ConvertToFIR.cpp
+++ flang/lib/Optimizer/HLFIR/Transforms/ConvertToFIR.cpp
@@ -105,7 +105,6 @@
           rhsType = fir::LogicalType::get(builder.getContext(), 4);
           rhsVal = builder.createConvert(loc, rhsType, rhsVal);
         }
-
         mlir::Value temp = builder.create<fir::AllocaOp>(loc, rhsType);
         builder.create<fir::StoreOp>(loc, rhsVal, temp);
         rhsExv = temp;
Index: flang/test/Lower/HLFIR/assignment-intrinsics.f90
===================================================================
--- flang/test/Lower/HLFIR/assignment-intrinsics.f90
+++ flang/test/Lower/HLFIR/assignment-intrinsics.f90
@@ -74,7 +74,8 @@
 ! CHECK-LABEL: func.func @_QPscalar_logical_2(
 ! CHECK:  %[[VAL_1:.*]]:2 = hlfir.declare {{.*}}  {uniq_name = "_QFscalar_logical_2Ex"} : (!fir.ref<!fir.logical<4>>) -> (!fir.ref<!fir.logical<4>>, !fir.ref<!fir.logical<4>>)
 ! CHECK:  %[[VAL_2:.*]] = arith.constant true
-! CHECK:  hlfir.assign %[[VAL_2]] to %[[VAL_1]]#0 : i1, !fir.ref<!fir.logical<4>>
+! CHECK:  %[[VAL_3:.*]] = fir.convert %[[VAL_2]] : (i1) -> !fir.logical<4>
+! CHECK:  hlfir.assign %[[VAL_3]] to %[[VAL_1]]#0 : !fir.logical<4>, !fir.ref<!fir.logical<4>>
 
 subroutine scalar_real_2(x)
   real :: x
Index: flang/test/Lower/HLFIR/expr-as-inquired.f90
===================================================================
--- flang/test/Lower/HLFIR/expr-as-inquired.f90
+++ flang/test/Lower/HLFIR/expr-as-inquired.f90
@@ -16,7 +16,8 @@
 ! CHECK:  %[[VAL_6:.*]] = fir.convert %[[VAL_5]] : (!fir.heap<!fir.array<?xf32>>) -> i64
 ! CHECK:  %[[VAL_7:.*]] = arith.constant 0 : i64
 ! CHECK:  %[[VAL_8:.*]] = arith.cmpi ne, %[[VAL_6]], %[[VAL_7]] : i64
-! CHECK:  hlfir.assign %[[VAL_8]] to %[[VAL_2]]#0 : i1, !fir.ref<!fir.logical<4>>
+! CHECK:  %[[VAL_9:.*]] = fir.convert %[[VAL_8]] : (i1) -> !fir.logical<4>
+! CHECK:  hlfir.assign %[[VAL_9]] to %[[VAL_2]]#0 : !fir.logical<4>, !fir.ref<!fir.logical<4>>
 ! CHECK:  return
 ! CHECK:  }
 
Index: flang/test/Lower/HLFIR/implicit-type-conversion.f90
===================================================================
--- /dev/null
+++ flang/test/Lower/HLFIR/implicit-type-conversion.f90
@@ -0,0 +1,137 @@
+! RUN: bbc -emit-fir -hlfir %s -o - | FileCheck %s
+
+! CHECK-LABEL:   func.func @_QPtest1(
+! CHECK-SAME:                        %[[VAL_0:.*]]: !fir.ref<i32> {fir.bindc_name = "x"},
+! CHECK-SAME:                        %[[VAL_1:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_name = "y"}) {
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_0]] {uniq_name = "_QFtest1Ex"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %[[VAL_1]] {uniq_name = "_QFtest1Ey"} : (!fir.ref<!fir.logical<4>>) -> (!fir.ref<!fir.logical<4>>, !fir.ref<!fir.logical<4>>)
+! CHECK:           %[[VAL_4:.*]] = fir.load %[[VAL_3]]#0 : !fir.ref<!fir.logical<4>>
+! CHECK:           %[[VAL_5:.*]] = fir.convert %[[VAL_4]] : (!fir.logical<4>) -> i32
+! CHECK:           hlfir.assign %[[VAL_5]] to %[[VAL_2]]#0 : i32, !fir.ref<i32>
+! CHECK:           return
+! CHECK:         }
+subroutine test1(x, y)
+  integer :: x
+  logical :: y
+  x = y
+end subroutine test1
+
+! CHECK-LABEL:   func.func @_QPtest2(
+! CHECK-SAME:                        %[[VAL_0:.*]]: !fir.ref<i32> {fir.bindc_name = "x"},
+! CHECK-SAME:                        %[[VAL_1:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_name = "y"}) {
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_0]] {uniq_name = "_QFtest2Ex"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %[[VAL_1]] {uniq_name = "_QFtest2Ey"} : (!fir.ref<!fir.logical<4>>) -> (!fir.ref<!fir.logical<4>>, !fir.ref<!fir.logical<4>>)
+! CHECK:           %[[VAL_4:.*]] = fir.load %[[VAL_2]]#0 : !fir.ref<i32>
+! CHECK:           %[[VAL_5:.*]] = fir.convert %[[VAL_4]] : (i32) -> !fir.logical<4>
+! CHECK:           hlfir.assign %[[VAL_5]] to %[[VAL_3]]#0 : !fir.logical<4>, !fir.ref<!fir.logical<4>>
+! CHECK:           return
+! CHECK:         }
+subroutine test2(x, y)
+  integer :: x
+  logical :: y
+  y = x
+end subroutine test2
+
+! CHECK-LABEL:   func.func @_QPtest3(
+! CHECK-SAME:                        %[[VAL_0:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_name = "x"},
+! CHECK-SAME:                        %[[VAL_1:.*]]: !fir.ref<i32> {fir.bindc_name = "y"}) {
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_0]] {uniq_name = "_QFtest3Ex"} : (!fir.ref<!fir.logical<4>>) -> (!fir.ref<!fir.logical<4>>, !fir.ref<!fir.logical<4>>)
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %[[VAL_1]] {uniq_name = "_QFtest3Ey"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %[[VAL_4:.*]] = fir.load %[[VAL_3]]#0 : !fir.ref<i32>
+! CHECK:           %[[VAL_5:.*]] = arith.constant 1 : i32
+! CHECK:           %[[VAL_6:.*]] = arith.cmpi eq, %[[VAL_4]], %[[VAL_5]] : i32
+! CHECK:           %[[VAL_7:.*]] = hlfir.no_reassoc %[[VAL_6]] : i1
+! CHECK:           %[[VAL_8:.*]] = fir.convert %[[VAL_7]] : (i1) -> !fir.logical<4>
+! CHECK:           hlfir.assign %[[VAL_8]] to %[[VAL_2]]#0 : !fir.logical<4>, !fir.ref<!fir.logical<4>>
+! CHECK:           return
+! CHECK:         }
+subroutine test3(x, y)
+  logical :: x
+  integer :: y
+  x = (y.eq.1)
+end subroutine test3
+
+! CHECK-LABEL:   func.func @_QPtest4(
+! CHECK-SAME:                        %[[VAL_0:.*]]: !fir.ref<i32> {fir.bindc_name = "x"},
+! CHECK-SAME:                        %[[VAL_1:.*]]: !fir.ref<i32> {fir.bindc_name = "y"}) {
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_0]] {uniq_name = "_QFtest4Ex"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %[[VAL_1]] {uniq_name = "_QFtest4Ey"} : (!fir.ref<i32>) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %[[VAL_4:.*]] = fir.load %[[VAL_3]]#0 : !fir.ref<i32>
+! CHECK:           %[[VAL_5:.*]] = arith.constant 1 : i32
+! CHECK:           %[[VAL_6:.*]] = arith.cmpi eq, %[[VAL_4]], %[[VAL_5]] : i32
+! CHECK:           %[[VAL_7:.*]] = hlfir.no_reassoc %[[VAL_6]] : i1
+! CHECK:           %[[VAL_8:.*]] = fir.convert %[[VAL_7]] : (i1) -> i32
+! CHECK:           hlfir.assign %[[VAL_8]] to %[[VAL_2]]#0 : i32, !fir.ref<i32>
+! CHECK:           return
+! CHECK:         }
+subroutine test4(x, y)
+  integer :: x
+  integer :: y
+  x = (y.eq.1)
+end subroutine test4
+
+! CHECK-LABEL:   func.func @_QPtest5(
+! CHECK-SAME:                        %[[VAL_0:.*]]: !fir.box<!fir.array<?xi32>> {fir.bindc_name = "x"},
+! CHECK-SAME:                        %[[VAL_1:.*]]: !fir.ref<!fir.logical<4>> {fir.bindc_name = "y"}) {
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_0]] {uniq_name = "_QFtest5Ex"} : (!fir.box<!fir.array<?xi32>>) -> (!fir.box<!fir.array<?xi32>>, !fir.box<!fir.array<?xi32>>)
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %[[VAL_1]] {uniq_name = "_QFtest5Ey"} : (!fir.ref<!fir.logical<4>>) -> (!fir.ref<!fir.logical<4>>, !fir.ref<!fir.logical<4>>)
+! CHECK:           %[[VAL_4:.*]] = fir.load %[[VAL_3]]#0 : !fir.ref<!fir.logical<4>>
+! CHECK:           %[[VAL_5:.*]] = fir.convert %[[VAL_4]] : (!fir.logical<4>) -> i32
+! CHECK:           hlfir.assign %[[VAL_5]] to %[[VAL_2]]#0 : i32, !fir.box<!fir.array<?xi32>>
+! CHECK:           return
+! CHECK:         }
+subroutine test5(x, y)
+  integer :: x(:)
+  logical :: y
+  x = y
+end subroutine test5
+
+! CHECK-LABEL:   func.func @_QPtest6(
+! CHECK-SAME:                        %[[VAL_0:.*]]: !fir.box<!fir.array<?xi32>> {fir.bindc_name = "x"},
+! CHECK-SAME:                        %[[VAL_1:.*]]: !fir.box<!fir.array<?x!fir.logical<4>>> {fir.bindc_name = "y"}) {
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_0]] {uniq_name = "_QFtest6Ex"} : (!fir.box<!fir.array<?xi32>>) -> (!fir.box<!fir.array<?xi32>>, !fir.box<!fir.array<?xi32>>)
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %[[VAL_1]] {uniq_name = "_QFtest6Ey"} : (!fir.box<!fir.array<?x!fir.logical<4>>>) -> (!fir.box<!fir.array<?x!fir.logical<4>>>, !fir.box<!fir.array<?x!fir.logical<4>>>)
+! CHECK:           %[[VAL_4:.*]] = arith.constant 0 : index
+! CHECK:           %[[VAL_5:.*]]:3 = fir.box_dims %[[VAL_3]]#0, %[[VAL_4]] : (!fir.box<!fir.array<?x!fir.logical<4>>>, index) -> (index, index, index)
+! CHECK:           %[[VAL_6:.*]] = fir.shape %[[VAL_5]]#1 : (index) -> !fir.shape<1>
+! CHECK:           %[[VAL_7:.*]] = hlfir.elemental %[[VAL_6]] : (!fir.shape<1>) -> !hlfir.expr<?xi32> {
+! CHECK:           ^bb0(%[[VAL_8:.*]]: index):
+! CHECK:             %[[VAL_9:.*]] = hlfir.designate %[[VAL_3]]#0 (%[[VAL_8]])  : (!fir.box<!fir.array<?x!fir.logical<4>>>, index) -> !fir.ref<!fir.logical<4>>
+! CHECK:             %[[VAL_10:.*]] = fir.load %[[VAL_9]] : !fir.ref<!fir.logical<4>>
+! CHECK:             %[[VAL_11:.*]] = fir.convert %[[VAL_10]] : (!fir.logical<4>) -> i32
+! CHECK:             hlfir.yield_element %[[VAL_11]] : i32
+! CHECK:           }
+! CHECK:           hlfir.assign %[[VAL_12:.*]] to %[[VAL_2]]#0 : !hlfir.expr<?xi32>, !fir.box<!fir.array<?xi32>>
+! CHECK:           hlfir.destroy %[[VAL_12]] : !hlfir.expr<?xi32>
+! CHECK:           return
+! CHECK:         }
+subroutine test6(x, y)
+  integer :: x(:)
+  logical :: y(:)
+  x = y
+end subroutine test6
+
+! CHECK-LABEL:   func.func @_QPtest7(
+! CHECK-SAME:                        %[[VAL_0:.*]]: !fir.box<!fir.array<?x!fir.logical<4>>> {fir.bindc_name = "x"},
+! CHECK-SAME:                        %[[VAL_1:.*]]: !fir.box<!fir.array<?xi32>> {fir.bindc_name = "y"}) {
+! CHECK:           %[[VAL_2:.*]]:2 = hlfir.declare %[[VAL_0]] {uniq_name = "_QFtest7Ex"} : (!fir.box<!fir.array<?x!fir.logical<4>>>) -> (!fir.box<!fir.array<?x!fir.logical<4>>>, !fir.box<!fir.array<?x!fir.logical<4>>>)
+! CHECK:           %[[VAL_3:.*]]:2 = hlfir.declare %[[VAL_1]] {uniq_name = "_QFtest7Ey"} : (!fir.box<!fir.array<?xi32>>) -> (!fir.box<!fir.array<?xi32>>, !fir.box<!fir.array<?xi32>>)
+! CHECK:           %[[VAL_4:.*]] = arith.constant 0 : index
+! CHECK:           %[[VAL_5:.*]]:3 = fir.box_dims %[[VAL_3]]#0, %[[VAL_4]] : (!fir.box<!fir.array<?xi32>>, index) -> (index, index, index)
+! CHECK:           %[[VAL_6:.*]] = fir.shape %[[VAL_5]]#1 : (index) -> !fir.shape<1>
+! CHECK:           %[[VAL_7:.*]] = hlfir.elemental %[[VAL_6]] : (!fir.shape<1>) -> !hlfir.expr<?x!fir.logical<4>> {
+! CHECK:           ^bb0(%[[VAL_8:.*]]: index):
+! CHECK:             %[[VAL_9:.*]] = hlfir.designate %[[VAL_3]]#0 (%[[VAL_8]])  : (!fir.box<!fir.array<?xi32>>, index) -> !fir.ref<i32>
+! CHECK:             %[[VAL_10:.*]] = fir.load %[[VAL_9]] : !fir.ref<i32>
+! CHECK:             %[[VAL_11:.*]] = fir.convert %[[VAL_10]] : (i32) -> !fir.logical<4>
+! CHECK:             hlfir.yield_element %[[VAL_11]] : !fir.logical<4>
+! CHECK:           }
+! CHECK:           hlfir.assign %[[VAL_12:.*]] to %[[VAL_2]]#0 : !hlfir.expr<?x!fir.logical<4>>, !fir.box<!fir.array<?x!fir.logical<4>>>
+! CHECK:           hlfir.destroy %[[VAL_12]] : !hlfir.expr<?x!fir.logical<4>>
+! CHECK:           return
+! CHECK:         }
+subroutine test7(x, y)
+  logical :: x(:)
+  integer :: y(:)
+  x = y
+end subroutine test7