Make step != 0 test in slice irrefutable (#133091)

ezyang · pytorchmergebot · commit a7912bf9dc39 · 2024-08-10T23:56:45.000Z
Signed-off-by: Edward Z. Yang <ezyang@meta.com> Pull Request resolved: #133091 Approved by: https://github.com/bdhirsh
diff --git a/aten/src/ATen/TensorIndexing.h b/aten/src/ATen/TensorIndexing.h
@@ -48,7 +48,9 @@ struct TORCH_API Slice final {
       step_ = std::move(step_index).value();
     }
 
-    TORCH_CHECK_VALUE(step_ != 0, "slice step cannot be zero");
+    TORCH_CHECK_VALUE(
+        step_.sym_ne(0).expect_true(__FILE__, __LINE__),
+        "slice step cannot be zero");
 
     if (!start_index.has_value()) {
       start_ = c10::SymInt(step_ < 0 ? INDEX_MAX : 0);
@@ -207,7 +209,9 @@ inline Tensor applySlice(
     const at::Device& self_device,
     const std::optional<SymIntArrayRef>& self_sizes) {
   // TODO: implement negative step
-  TORCH_CHECK_VALUE(step > 0, "step must be greater than zero");
+  TORCH_CHECK_VALUE(
+      step.sym_gt(0).expect_true(__FILE__, __LINE__),
+      "step must be greater than zero");
 
   // See NOTE [nested tensor size for indexing]
   if (self_sizes.has_value()) {
