Version guard for AccumulateGrad::add (#1768)

Summary:
Pull Request resolved: #1768

When running `fbpkg build //monarch:monarch_dev` on 3279935a10 we encounter a compile time error that seems to stem from compiling with different versions of PyTorch. We might want to update our build chain. It seems monarch is once compiled against a third part 2.8.0 pytorch and once against the fbcode version. This version guard helps with this version drift if that's intended.

Reviewed By: pzhan9, zdevito, soulitzer

Differential Revision: D86363543

fbshipit-source-id: cb344e3363595cfe6aed22a27ac8eb8075fae351

Author: cpuhrsch

python/monarch/gradient/_gradient_generator.cpp

@@ -23,6 +23,12 @@
 #include <torch/csrc/autograd/python_function.h> // @manual=//caffe2:torch_extension
 #include <torch/extension.h> // @manual=//caffe2:torch_extension
 
+#define TORCH_VERSION_NEWER_THAN(major, minor, patch)                   \
+  ((TORCH_VERSION_MAJOR > (major)) ||                                   \
+   (TORCH_VERSION_MAJOR == (major) && TORCH_VERSION_MINOR > (minor)) || \
+   (TORCH_VERSION_MAJOR == (major) && TORCH_VERSION_MINOR == (minor) && \
+    TORCH_VERSION_PATCH > (patch)))
+
 using torch::autograd::Edge;
 using torch::autograd::InputBuffer;
 using torch::autograd::Node;
@@ -420,12 +426,20 @@ struct GradientGenerator {
     DEBUG_PRINT(
         "// add: " << node->node->name()
                    << ", input_nr=" << static_cast<int>(input_nr) << "\n");
+#if TORCH_VERSION_NEWER_THAN(2, 8, 0)
     realInputBuffer(node).add(
         input_nr,
         check_and_reduce(node->node, input_nr, std::move(t)),
         std::nullopt,
         std::nullopt,
         node->node);
+#else
+    realInputBuffer(node).add(
+        input_nr,
+        check_and_reduce(node->node, input_nr, std::move(t)),
+        std::nullopt,
+        std::nullopt);
+#endif
   }
 
   InputBuffer& realInputBuffer(NodeState* state) {