feat: replace view with reshape during lowering

Signed-off-by: Ruoqian Guo <ruoqiang@nvidia.com>

core/lowering/lowering.cpp

@@ -45,6 +45,7 @@ void LowerGraph(std::shared_ptr<torch::jit::Graph>& g, LowerInfo lower_info) {
   passes::ReduceToOperation(g);
   passes::ReduceGelu(g);
   passes::RemoveContiguous(g);
+  passes::ViewToReshape(g);
   passes::RemoveDropout(g);
   passes::LinearToAddMM(g);
   passes::Conv1DToConvolution(g);

core/lowering/passes/BUILD

@@ -20,6 +20,7 @@ cc_library(
         "reduce_gelu.cpp",
         "remove_bn_dim_check.cpp",
         "remove_contiguous.cpp",
+        "view_to_reshape.cpp",
         "remove_dropout.cpp",
         "remove_nops.cpp",
         "silu_to_sigmoid_multiplication.cpp",

core/lowering/passes/passes.h

@@ -24,6 +24,7 @@ void ReduceGelu(std::shared_ptr<torch::jit::Graph>& graph);
 void MarkNodesForFallback(std::shared_ptr<torch::jit::Graph>& g, bool delete_delims);
 void RemoveBNDimCheck(std::shared_ptr<torch::jit::Graph> graph);
 void RemoveContiguous(std::shared_ptr<torch::jit::Graph>& graph);
+void ViewToReshape(std::shared_ptr<torch::jit::Graph>& graph);
 void RemoveDropout(std::shared_ptr<torch::jit::Graph>& graph);
 void RemoveNOPs(std::shared_ptr<torch::jit::Graph> graph);
 void UnpackAddMM(std::shared_ptr<torch::jit::Graph>& graph);

core/lowering/passes/view_to_reshape.cpp

@@ -0,0 +1,31 @@
+#include <torch/csrc/jit/passes/subgraph_rewrite.h>
+#include "core/util/prelude.h"
+
+namespace torch_tensorrt {
+namespace core {
+namespace lowering {
+namespace passes {
+
+void ViewToReshape(std::shared_ptr<torch::jit::Graph>& graph) {
+  std::string view_pattern = R"IR(
+        graph(%x, %1):
+            %out : Tensor = aten::view(%x, %1)
+            return (%out))IR";
+
+  std::string reshape_pattern = R"IR(
+        graph(%x, %1):
+            %out : Tensor = aten::reshape(%x, %1)
+            return (%out))IR";
+
+  // replace aten::view with aten::reshape
+  torch::jit::SubgraphRewriter map_view_to_reshape;
+  map_view_to_reshape.RegisterRewritePattern(view_pattern, reshape_pattern);
+  map_view_to_reshape.runOnGraph(graph);
+
+  LOG_GRAPH("Post lowering of aten::view -> " << *graph);
+}
+
+} // namespace passes
+} // namespace lowering
+} // namespace core
+} // namespace torch_tensorrt

tests/core/lowering/BUILD

@@ -50,6 +50,10 @@ lowering_test(
     name = "test_remove_detach_pass",
 )
 
+lowering_test(
+    name = "test_view_to_reshape_pass",
+)
+
 lowering_test(
     name = "test_operator_aliasing_pass",
 )
@@ -75,6 +79,7 @@ test_suite(
         ":test_operator_aliasing_pass",
         ":test_remove_contiguous_pass",
         ":test_remove_detach_pass",
+        ":test_view_to_reshape_pass",
         ":test_remove_dropout_pass",
         ":test_reduce_to_pass",
         ":test_reduce_gelu",

tests/core/lowering/test_view_to_reshape_pass.cpp

@@ -0,0 +1,35 @@
+#include <string>
+#include "core/compiler.h"
+#include "core/lowering/passes/passes.h"
+#include "gtest/gtest.h"
+#include "tests/util/util.h"
+#include "torch/csrc/jit/ir/irparser.h"
+#include "torch/csrc/jit/ir/subgraph_matcher.h"
+
+TEST(LoweringPasses, ViewToReshapeCorrectly) {
+  std::string source_graph = R"IR(
+    graph(%x : Tensor, %1, %1.1):
+        %0 : int = prim::Constant[value=0]()
+        %2 : Tensor = aten::permute(%x, %1)
+        %3 : Tensor = aten::contiguous(%2, %0)
+        %4 : Tensor = aten::view(%3, %1.1)
+        return (%4))IR";
+  std::string target_graph = R"IR(
+    graph(%x : Tensor, %1, %1.1):
+        %0 : int = prim::Constant[value=0]()
+        %2 : Tensor = aten::permute(%x, %1)
+        %4 : Tensor = aten::reshape(%2, %1.1)
+        return (%4))IR";
+
+  torch_tensorrt::core::util::logging::get_logger().set_reportable_log_level(
+      torch_tensorrt::core::util::logging::LogLevel::kGRAPH);
+  auto sg = std::make_shared<torch::jit::Graph>();
+  torch::jit::parseIR(source_graph, &*sg);
+  torch_tensorrt::core::lowering::passes::RemoveContiguous(sg);
+  torch_tensorrt::core::lowering::passes::ViewToReshape(sg);
+
+  auto tg = std::make_shared<torch::jit::Graph>();
+  torch::jit::parseIR(target_graph, &*tg);
+
+  ASSERT_TRUE(!torch::jit::findPatternMatches(*tg, *sg).empty());
+}