Improve test a bit to make sure IVs are used as expected.

Author: jsjodin

flang/test/Lower/OpenMP/wsloop-tile.f90

@@ -13,14 +13,23 @@ program wsloop_tile
   c=50
   x=0
 
-  !CHECK: omp.loop_nest
+  !CHECK: omp.loop_nest (%[[IV_0:.*]], %[[IV_1:.*]], %[[IV_2:.*]]) : i32
   !CHECK-SAME: tiles(2, 5, 10)
 
   !$omp do
   !$omp tile sizes(2,5,10)
   do i = 1, a
      do j= 1, b
         do k = 1, c
+  !CHECK: hlfir.assign %[[IV_0]] to %[[IV_0A:.*]] : i32
+  !CHECK: hlfir.assign %[[IV_1]] to %[[IV_1A:.*]] : i32
+  !CHECK: hlfir.assign %[[IV_2]] to %[[IV_2A:.*]] : i32
+  !CHECK: %[[IVV_0:.*]] = fir.load %[[IV_0A]]
+  !CHECK: %[[SUM0:.*]] = arith.addi %{{.*}}, %[[IVV_0]] : i32
+  !CHECK: %[[IVV_1:.*]] = fir.load %[[IV_1A]]
+  !CHECK: %[[SUM1:.*]] = arith.addi %[[SUM0]], %[[IVV_1]] : i32
+  !CHECK: %[[IVV_2:.*]] = fir.load %[[IV_2A]]
+  !CHECK: %[[SUM2:.*]] = arith.addi %[[SUM1]], %[[IVV_2]] : i32
            x = x + i + j + k
         end do
      end do