taking out "return" statements from aggregation optimization

Differential Revision: D62334013 fbshipit-source-id: 10ab17eb8eeb03346d914f8593c4890722cf0a66
facebook · Sep 11, 2024 · ecb219e · ecb219e
1 parent a731fdf
commit ecb219e
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diff --git a/opt/outliner/MethodClosures.cpp b/opt/outliner/MethodClosures.cpp
@@ -139,6 +139,20 @@ std::shared_ptr<const ReducedControlFlowGraph> reduce_cfg(
     DexMethod* method, std::optional<uint64_t> split_block_size) {
   auto code = method->get_code();
   auto& cfg = code->cfg();
+  for (auto* block : cfg.blocks()) {
+    auto* goes_to_block = block->goes_to_only_edge();
+    if (goes_to_block == nullptr) {
+      continue;
+    }
+    auto first_insn_it = goes_to_block->get_first_insn();
+    if (first_insn_it == goes_to_block->end()) {
+      continue;
+    }
+    if (opcode::is_a_return(first_insn_it->insn->opcode())) {
+      block->push_back(new IRInstruction(*first_insn_it->insn));
+      cfg.delete_succ_edges(block);
+    }
+  }
   cfg.remove_unreachable_blocks();
   if (split_block_size) {
     split_blocks(method, cfg, *split_block_size);

diff --git a/test/unit/MethodSplittingTest.cpp b/test/unit/MethodSplittingTest.cpp
@@ -862,3 +862,91 @@ TEST_F(MethodSplitterTest, DontSplitLoadParamChains) {
   ASSERT_EQ(m->get_code()->cfg().blocks().size(), 1);
   m->get_code()->clear_cfg();
 }
+
+TEST_F(MethodSplitterTest, UndupReturns) {
+  auto before = R"(
+    (
+      (load-param v0)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (switch v0 (:a :b :c :d))
+    (:common)
+      (return v0)
+    (:a 0)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (goto :common)
+    (:b 1)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (goto :common)
+    (:c 2)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (goto :common)
+    (:d 3)
+      (add-int v0 v0 v0)
+      (goto :common)
+    ))";
+  auto after = R"(
+    (
+      (load-param v0)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (switch v0 (:b :a))
+      (.pos:dbg_0 "LFoo;.bar:(I)I" RedexGenerated 0)
+      (invoke-static (v0) "LFoo;.bar$split$cold0:(I)I")
+      (move-result v0)
+      (return v0)
+    (:b 1)
+      (invoke-static (v0) "LFoo;.bar$split$cold2:(I)I")
+      (move-result v0)
+      (return v0)
+    (:a 0)
+      (invoke-static (v0) "LFoo;.bar$split$cold1:(I)I")
+      (move-result v0)
+      (return v0)
+    ))";
+  auto split0cd = R"(
+    (
+      (load-param v0)
+      (switch v0 (:d :c))
+      (return v0)
+    (:d 3)
+      (add-int v0 v0 v0)
+      (return v0)
+    (:c 2)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (return v0)
+    ))";
+  auto split1a = R"(
+    (
+      (load-param v0)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (return v0)
+    ))";
+  auto split2b = R"(
+    (
+      (load-param v0)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (add-int v0 v0 v0)
+      (return v0)
+    ))";
+  auto res =
+      test("(I)I",
+           before,
+           defaultConfig(),
+           {std::make_pair<std::string, std::string>("", after),
+            std::make_pair<std::string, std::string>("split$cold0", split0cd),
+            std::make_pair<std::string, std::string>("split$cold1", split1a),
+            std::make_pair<std::string, std::string>("split$cold2", split2b)});
+  ASSERT_TRUE(res);
+}