commit 2477320a8d9de58ede68e2645ea53c10f71dcd57
author Aart Bik <ajcbik@google.com> Thu Apr 26 10:28:51 2018 -0700
committer Aart Bik <ajcbik@google.com> Thu Apr 26 10:28:51 2018 -0700
tree f428a6856e10d8ebaff0bb2da544a8d41c35ab77
parent 5a87e19e4bf1b6719c2aad3effde1b38d2c3085c

Step 1 of 2: conditional passes.

Rationale:
The change adds a return value to Run() in preparation of
conditional pass execution. The value returned by Run() is
best effort, returning false means no optimizations were
applied or no useful information was obtained. I filled
in a few cases with more exact information, others
still just return true. In addition, it integrates inlining
as a regular pass, avoiding the ugly "break" into
optimizations1 and optimziations2.

Bug: b/78171933, b/74026074

Test: test-art-host,target
Change-Id: Ia39c5c83c01dcd79841e4b623917d61c754cf075

compiler/optimizing/loop_optimization.cc

diff --git a/compiler/optimizing/loop_optimization.cc b/compiler/optimizing/loop_optimization.cc
index 1462404..7f1b319 100644
--- a/compiler/optimizing/loop_optimization.cc
+++ b/compiler/optimizing/loop_optimization.cc
@@ -608,11 +608,11 @@
                                                       global_allocator_)) {
 }
 
-void HLoopOptimization::Run() {
+bool HLoopOptimization::Run() {
   // Skip if there is no loop or the graph has try-catch/irreducible loops.
   // TODO: make this less of a sledgehammer.
   if (!graph_->HasLoops() || graph_->HasTryCatch() || graph_->HasIrreducibleLoops()) {
-    return;
+    return false;
   }
 
   // Phase-local allocator.
@@ -620,7 +620,7 @@
   loop_allocator_ = &allocator;
 
   // Perform loop optimizations.
-  LocalRun();
+  bool didLoopOpt = LocalRun();
   if (top_loop_ == nullptr) {
     graph_->SetHasLoops(false);  // no more loops
   }
@@ -628,13 +628,16 @@
   // Detach.
   loop_allocator_ = nullptr;
   last_loop_ = top_loop_ = nullptr;
+
+  return didLoopOpt;
 }
 
 //
 // Loop setup and traversal.
 //
 
-void HLoopOptimization::LocalRun() {
+bool HLoopOptimization::LocalRun() {
+  bool didLoopOpt = false;
   // Build the linear order using the phase-local allocator. This step enables building
   // a loop hierarchy that properly reflects the outer-inner and previous-next relation.
   ScopedArenaVector<HBasicBlock*> linear_order(loop_allocator_->Adapter(kArenaAllocLinearOrder));
@@ -666,7 +669,7 @@
     vector_map_ = &map;
     vector_permanent_map_ = &perm;
     // Traverse.
-    TraverseLoopsInnerToOuter(top_loop_);
+    didLoopOpt = TraverseLoopsInnerToOuter(top_loop_);
     // Detach.
     iset_ = nullptr;
     reductions_ = nullptr;
@@ -674,6 +677,7 @@
     vector_map_ = nullptr;
     vector_permanent_map_ = nullptr;
   }
+  return didLoopOpt;
 }
 
 void HLoopOptimization::AddLoop(HLoopInformation* loop_info) {