Revert "ART: Removes SuspendCheck for plain loops with a low trip count."

This reverts commit 3de02fb67de386368c9fe39ab5a0133afcf1d785.

Reason for revert: b/201413752

Change-Id: I8a3a56cfb81fa88f49992615696260dfbc79bb67

1 files changed, 2 insertions, 18 deletions

diff --git a/compiler/optimizing/loop_optimization.h b/compiler/optimizing/loop_optimization.h
index 0ca16b543d..d3583ed8a6 100644
--- a/compiler/optimizing/loop_optimization.h
+++ b/compiler/optimizing/loop_optimization.h
@@ -47,11 +47,6 @@ class HLoopOptimization : public HOptimization {
 
   static constexpr const char* kLoopOptimizationPassName = "loop_optimization";
 
-  // The maximum number of total instructions (trip_count * instruction_count),
-  // where the optimization of removing SuspendChecks from the loop header could
-  // be performed.
-  static constexpr int64_t kMaxTotalInstRemoveSuspendCheck = 128;
-
  private:
   /**
    * A single loop inside the loop hierarchy representation.
@@ -168,19 +163,8 @@ class HLoopOptimization : public HOptimization {
   // should be actually applied.
   bool TryFullUnrolling(LoopAnalysisInfo* analysis_info, bool generate_code = true);
 
-  // Tries to remove SuspendCheck for plain loops with a low trip count. The
-  // SuspendCheck in the codegen makes sure that the thread can be interrupted
-  // during execution for GC. Not being able to do so might decrease the
-  // responsiveness of GC when a very long loop or a long recursion is being
-  // executed. However, for plain loops with a small trip count, the removal of
-  // SuspendCheck should not affect the GC's responsiveness by a large margin.
-  // Consequently, since the thread won't be interrupted for plain loops, it is
-  // assumed that the performance might increase by removing SuspendCheck.
-  bool TryToRemoveSuspendCheckFromLoopHeader(LoopAnalysisInfo* analysis_info,
-                                             bool generate_code = true);
-
-  // Tries to apply scalar loop optimizations.
-  bool TryLoopScalarOpts(LoopNode* node);
+  // Tries to apply scalar loop peeling and unrolling.
+  bool TryPeelingAndUnrolling(LoopNode* node);
 
   //
   // Vectorization analysis and synthesis.