diff --git a/python/tvm/topi/cuda/sort.py b/python/tvm/topi/cuda/sort.py
index ff5cc0681ad2..ca832ef0ef36 100644
--- a/python/tvm/topi/cuda/sort.py
+++ b/python/tvm/topi/cuda/sort.py
@@ -23,6 +23,7 @@
 from ..transform import strided_slice, transpose
 from .. import tag
 from ..utils import ceil_div, swap
+from ..math import cast
 
 
 def _schedule_sort(outs):
@@ -142,6 +143,8 @@ def bottom_up_merge(source, dest, source_idx, dest_idx, start, middle, end, even
         """
         # pylint: disable=arguments-out-of-order
         # initialize iterators
+        i = ib.allocate("int64", (1,), name="i", scope="local")
+        j = ib.allocate("int64", (1,), name="j", scope="local")
         i[0] = start
         j[0] = middle
         # set up indexes
@@ -189,12 +192,13 @@ def assign_j():
 
     def mergesort(source, dest, source_idx, dest_idx, size, width, even):
         # calculate the start, mid, and end points of this section
-        start[0] = width * tid
-        with ib.if_scope(start[0] < size):
-            middle[0] = tvm.te.min(start[0] + tvm.tir.indexdiv(width, 2), size)
-            end[0] = tvm.te.min(start[0] + width, size)
-            ## merge the start->middle and middle->end arrays
-            bottom_up_merge(source, dest, source_idx, dest_idx, start[0], middle[0], end[0], even)
+        start = width * tid
+
+        with ib.if_scope(start < size):
+            middle = cast(tvm.te.min(start + tvm.tir.indexdiv(width, 2), size), "int64")
+            end = cast(tvm.te.min(start + width, size), "int64")
+            # merge the start->middle and middle->end arrays
+            bottom_up_merge(source, dest, source_idx, dest_idx, start, middle, end, even)
 
     lim = tvm.tir.generic.cast(
         tvm.tir.ceil(tvm.tir.log2(tvm.tir.generic.cast(size, "float64"))), "int64"
@@ -203,11 +207,6 @@ def mergesort(source, dest, source_idx, dest_idx, size, width, even):
         width = 2 << l2_width
         # Define and launch the cuda kernel
         with ib.new_scope():
-            i = ib.allocate("int64", (1,), name="i", scope="local")
-            j = ib.allocate("int64", (1,), name="j", scope="local")
-            start = ib.allocate("int64", (1,), name="start", scope="local")
-            middle = ib.allocate("int64", (1,), name="middle", scope="local")
-            end = ib.allocate("int64", (1,), name="end", scope="local")
             tx = te.thread_axis("threadIdx.x")
             bx = te.thread_axis("blockIdx.x")
             ib.scope_attr(tx, "thread_extent", nthread_tx)
diff --git a/tests/python/topi/python/test_topi_sort.py b/tests/python/topi/python/test_topi_sort.py
index 626218f30144..85a35488ab22 100644
--- a/tests/python/topi/python/test_topi_sort.py
+++ b/tests/python/topi/python/test_topi_sort.py
@@ -75,7 +75,7 @@ def check_device(device):
         f(tvm_data, tvm_out)
         tvm.testing.assert_allclose(tvm_out.asnumpy(), np_sort, rtol=1e0)
 
-    for device in ["llvm", "cuda", "opencl"]:
+    for device in ["llvm", "cuda", "opencl", "vulkan", "nvptx"]:
         check_device(device)
 
 
@@ -115,7 +115,7 @@ def check_device(device):
         f(tvm_data, tvm_out)
         tvm.testing.assert_allclose(tvm_out.asnumpy(), np_indices.astype(data_dtype), rtol=1e0)
 
-    for device in ["llvm", "cuda", "opencl"]:
+    for device in ["llvm", "cuda", "opencl", "vulkan", "nvptx"]:
         check_device(device)
 
 
@@ -167,7 +167,7 @@ def check_device(device):
         else:
             tvm.testing.assert_allclose(tvm_res[0].asnumpy(), np_indices)
 
-    for device in ["llvm", "cuda", "opencl"]:
+    for device in ["llvm", "cuda", "opencl", "vulkan", "nvptx"]:
         check_device(device)