[ExecuTorch][WebGPU] slice_copy Double-arg scalar handling + view_copy/alias glue

backends/webgpu/runtime/ops/slice/Slice.cpp

@@ -14,6 +14,7 @@
 
 #include <webgpu/webgpu.h>
 
+#include <cmath>
 #include <cstdint>
 #include <stdexcept>
 #include <string>
@@ -30,14 +31,31 @@ struct SliceParams {
   uint32_t _pad;
 };
 
-// Read scalar arg: Int->value (INT64_MAX->default), Null->default, else throw.
+// Read scalar arg: Int->value (INT64_MAX->default), Double->truncated int if
+// integral (the edge dialect may serialize an integer index as a float, e.g.
+// a 0 start; a fractional Double throws, it is not a valid index),
+// Null->default, else throw.
 int64_t
 read_scalar(WebGPUGraph& graph, int id, int64_t dflt, const char* what) {
   switch (graph.get_value_type(id)) {
     case WebGPUGraph::ValueType::Int: {
       const int64_t v = graph.get_int(id);
       return v == INT64_MAX ? dflt : v;
     }
+    case WebGPUGraph::ValueType::Double: {
+      const double d = graph.get_double(id);
+      // Casting a NaN or out-of-int64-range double is undefined behavior;
+      // reject before the cast, not after.
+      if (std::isnan(d) || d < -9223372036854775808.0 ||
+          d >= 9223372036854775808.0) {
+        throw std::runtime_error(std::string("slice: non-integral ") + what);
+      }
+      const int64_t v = static_cast<int64_t>(d);
+      if (static_cast<double>(v) != d) {
+        throw std::runtime_error(std::string("slice: non-integral ") + what);
+      }
+      return v;
+    }
     case WebGPUGraph::ValueType::Null:
       return dflt;
     default:
@@ -46,7 +64,8 @@ read_scalar(WebGPUGraph& graph, int id, int64_t dflt, const char* what) {
   }
 }
 
-// Read a slice index (start/end) that MAY be a dynamic SymInt; else Int/Null.
+// Read a slice index (start/end) that MAY be a dynamic SymInt; else Int/Double
+// (truncated int if integral, mirrors read_scalar)/Null.
 int64_t read_index(WebGPUGraph& graph, int id, int64_t dflt) {
   switch (graph.get_value_type(id)) {
     case WebGPUGraph::ValueType::SymInt:
@@ -55,6 +74,20 @@ int64_t read_index(WebGPUGraph& graph, int id, int64_t dflt) {
       const int64_t v = graph.get_int(id);
       return v == INT64_MAX ? dflt : v;
     }
+    case WebGPUGraph::ValueType::Double: {
+      const double d = graph.get_double(id);
+      // Casting a NaN or out-of-int64-range double is undefined behavior;
+      // reject before the cast, not after.
+      if (std::isnan(d) || d < -9223372036854775808.0 ||
+          d >= 9223372036854775808.0) {
+        throw std::runtime_error("slice: non-integral start/end index");
+      }
+      const int64_t v = static_cast<int64_t>(d);
+      if (static_cast<double>(v) != d) {
+        throw std::runtime_error("slice: non-integral start/end index");
+      }
+      return v;
+    }
     case WebGPUGraph::ValueType::Null:
       return dflt;
     default:

backends/webgpu/runtime/ops/view_copy/ViewCopy.cpp

@@ -103,6 +103,9 @@ void clone_impl(WebGPUGraph& graph, const std::vector<int>& args) {
 WEBGPU_REGISTER_OPERATORS {
   WEBGPU_REGISTER_OP(aten.view_copy.default, view_copy_impl);
   WEBGPU_REGISTER_OP(aten.clone.default, clone_impl);
+  WEBGPU_REGISTER_OP(aten.alias_copy.default, clone_impl);
+  // _clone_dim_order ignores dim_order (AOT pass elides via shape+dtype).
+  WEBGPU_REGISTER_OP(dim_order_ops._clone_dim_order.default, clone_impl);
 }
 
 } // namespace executorch::backends::webgpu