fix trivial index map [] -> [0]

Author: wrongtest

src/tir/ir/index_map.cc

@@ -218,7 +218,7 @@ Array<Range> IndexMapNode::MapRanges(const Array<Range>& ranges, arith::Analyzer
     }
   }
   auto output_dtype = [&]() {
-    int max_bits = 0;
+    int max_bits = ranges.empty() ? 32 : 0;
     for (const auto& range : ranges) {
       max_bits = std::max(max_bits, range->extent.dtype().bits());
     }

src/tir/schedule/primitive/layout_transformation.cc

@@ -1464,6 +1464,10 @@ void TransformBlockLayout(ScheduleState self, const StmtSRef& block_sref,
   }
 
   // Step 6: Do the actual replacement
+  if (scope_sref->StmtAs<BlockNode>()) {
+    ICHECK(new_loop_vars.empty()) << "Invalid block to loop replacement due to layout transform "
+                                  << index_map;
+  }
   self->Replace(scope_sref, body, {{block, new_block}});
 }