check against IntImm instead of Var

Author: Masahiro Masuda

python/tvm/topi/cuda/scan.py

@@ -105,7 +105,7 @@ def exclusive_scan_ir(data, output, reduction=None, binop=tvm.tir.generic.add, i
         size_cast_dtype = "float64"
         target = tvm.target.Target.current()
 
-        if "vulkan" in str(target) and isinstance(scan_axis_size, tvm.tir.expr.Var):
+        if "vulkan" in str(target) and not isinstance(scan_axis_size, tvm.tir.expr.IntImm):
             # SPIRV seems to have an issue with float64 intrinsic
             # TODO(masahi): Eliminate this concern by adding TIR level CSE
             msg = """