diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -1702,9 +1702,12 @@
 IntrinsicLibrary::genElementalCall<IntrinsicLibrary::ExtendedGenerator>(
     ExtendedGenerator generator, llvm::StringRef name, mlir::Type resultType,
     llvm::ArrayRef<fir::ExtendedValue> args, bool outline) {
-  for (const fir::ExtendedValue &arg : args)
-    if (!arg.getUnboxed() && !arg.getCharBox())
+  for (const fir::ExtendedValue &arg : args) {
+    auto *box = arg.getBoxOf<fir::BoxValue>();
+    if (!arg.getUnboxed() && !arg.getCharBox() &&
+        !(box && fir::isPolymorphicType(fir::getBase(*box).getType())))
       fir::emitFatalError(loc, "nonscalar intrinsic argument");
+  }
   if (outline)
     return outlineInExtendedWrapper(generator, name, resultType, args);
   return std::invoke(generator, *this, resultType, args);
diff --git a/flang/test/Lower/polymorphic-temp.f90 b/flang/test/Lower/polymorphic-temp.f90
--- a/flang/test/Lower/polymorphic-temp.f90
+++ b/flang/test/Lower/polymorphic-temp.f90
@@ -185,4 +185,26 @@
 ! CHECK: %[[MATRIX_NONE:.*]] = fir.convert %[[MATRIX]] : (!fir.class<!fir.array<?x?x!fir.type<_QMpoly_tmpTp1{a:i32}>>>) -> !fir.box<none>
 ! CHECK: %{{.*}} = fir.call @_FortranATranspose(%[[RES_BOX_NONE]], %[[MATRIX_NONE]], %{{.*}}, %{{.*}}) {{.*}} : (!fir.ref<!fir.box<none>>, !fir.box<none>, !fir.ref<i8>, i32) -> none
 
+  subroutine check_scalar(a)
+    class(p1), intent(in) :: a
+  end subroutine
+
+  subroutine test_merge_intrinsic(a, b)
+    class(p1), intent(in) :: a, b
+
+    call check_scalar(merge(a, b, a%a > b%a))
+  end subroutine
+
+! CHECK-LABEL: func.func @_QMpoly_tmpPtest_merge_intrinsic(
+! CHECK-SAME: %[[ARG0:.*]]: !fir.class<!fir.type<_QMpoly_tmpTp1{a:i32}>> {fir.bindc_name = "a"}, %[[ARG1:.*]]: !fir.class<!fir.type<_QMpoly_tmpTp1{a:i32}>> {fir.bindc_name = "b"}) {
+! CHECK: %[[FIELD_A:.*]] = fir.field_index a, !fir.type<_QMpoly_tmpTp1{a:i32}>
+! CHECK: %[[COORD_A:.*]] = fir.coordinate_of %[[ARG0]], %[[FIELD_A]] : (!fir.class<!fir.type<_QMpoly_tmpTp1{a:i32}>>, !fir.field) -> !fir.ref<i32>
+! CHECK: %[[LOAD_A1:.*]] = fir.load %[[COORD_A]] : !fir.ref<i32>
+! CHECK: %[[FIELD_A:.*]] = fir.field_index a, !fir.type<_QMpoly_tmpTp1{a:i32}>
+! CHECK: %[[COORD_A:.*]] = fir.coordinate_of %[[ARG1]], %[[FIELD_A]] : (!fir.class<!fir.type<_QMpoly_tmpTp1{a:i32}>>, !fir.field) -> !fir.ref<i32>
+! CHECK: %[[LOAD_A2:.*]] = fir.load %[[COORD_A]] : !fir.ref<i32>
+! CHECK: %[[CMPI:.*]] = arith.cmpi sgt, %[[LOAD_A1]], %[[LOAD_A2]] : i32
+! CHECK: %[[SELECT:.*]] = arith.select %[[CMPI]], %[[ARG0]], %[[ARG1]] : !fir.class<!fir.type<_QMpoly_tmpTp1{a:i32}>>
+! CHECK: fir.call @_QMpoly_tmpPcheck_scalar(%[[SELECT]]) {{.*}} : (!fir.class<!fir.type<_QMpoly_tmpTp1{a:i32}>>) -> ()
+
 end module