Handle variable DIM properly.

Author: vzakhari

flang/lib/Lower/HlfirIntrinsics.cpp

@@ -405,9 +405,16 @@ mlir::Value HlfirCShiftLowering::lowerImpl(
     mlir::Type stmtResultType) {
   auto operands = getOperandVector(loweredActuals, argLowering);
   assert(operands.size() == 3);
-  // If DIM is not present, drop the last element which is a null Value.
-  if (!operands[2])
+  mlir::Value dim = operands[2];
+  if (!dim) {
+    // If DIM is not present, drop the last element which is a null Value.
     operands.truncate(2);
+  } else {
+    // If DIM is present, then dereference it if it is a ref.
+    dim = hlfir::loadTrivialScalar(loc, builder, hlfir::Entity{dim});
+    operands[2] = dim;
+  }
+
   mlir::Type resultType = computeResultType(operands[0], stmtResultType);
   return createOp<hlfir::CShiftOp>(resultType, operands);
 }

flang/test/Lower/HLFIR/cshift.f90

@@ -195,3 +195,24 @@ subroutine cshift10(a, s)
 ! CHECK:           hlfir.destroy %[[VAL_7]] : !hlfir.expr<?x!fir.type<_QMtypesTt>?>
 ! CHECK:           return
 ! CHECK:         }
+
+! 1d shift by scalar with variable dim
+subroutine cshift11(a, s, d)
+  integer :: a(:), s, d
+  a = CSHIFT(a, 2, d)
+end subroutine
+! CHECK-LABEL:   func.func @_QPcshift11(
+! CHECK-SAME:                           %[[VAL_0:.*]]: !fir.box<!fir.array<?xi32>> {fir.bindc_name = "a"},
+! CHECK-SAME:                           %[[VAL_1:.*]]: !fir.ref<i32> {fir.bindc_name = "s"},
+! CHECK-SAME:                           %[[VAL_2:.*]]: !fir.ref<i32> {fir.bindc_name = "d"}) {
+! CHECK:           %[[VAL_3:.*]] = fir.dummy_scope : !fir.dscope
+! CHECK:           %[[VAL_4:.*]]:2 = hlfir.declare %[[VAL_0]] dummy_scope %[[VAL_3]] {uniq_name = "_QFcshift11Ea"} : (!fir.box<!fir.array<?xi32>>, !fir.dscope) -> (!fir.box<!fir.array<?xi32>>, !fir.box<!fir.array<?xi32>>)
+! CHECK:           %[[VAL_5:.*]]:2 = hlfir.declare %[[VAL_2]] dummy_scope %[[VAL_3]] {uniq_name = "_QFcshift11Ed"} : (!fir.ref<i32>, !fir.dscope) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %[[VAL_6:.*]]:2 = hlfir.declare %[[VAL_1]] dummy_scope %[[VAL_3]] {uniq_name = "_QFcshift11Es"} : (!fir.ref<i32>, !fir.dscope) -> (!fir.ref<i32>, !fir.ref<i32>)
+! CHECK:           %[[VAL_7:.*]] = arith.constant 2 : i32
+! CHECK:           %[[VAL_8:.*]] = fir.load %[[VAL_5]]#0 : !fir.ref<i32>
+! CHECK:           %[[VAL_9:.*]] = hlfir.cshift %[[VAL_4]]#0 %[[VAL_7]] dim %[[VAL_8]] : (!fir.box<!fir.array<?xi32>>, i32, i32) -> !hlfir.expr<?xi32>
+! CHECK:           hlfir.assign %[[VAL_9]] to %[[VAL_4]]#0 : !hlfir.expr<?xi32>, !fir.box<!fir.array<?xi32>>
+! CHECK:           hlfir.destroy %[[VAL_9]] : !hlfir.expr<?xi32>
+! CHECK:           return
+! CHECK:         }