commit cf43fb6a1e676cc6bbc04c6591640f18643b1839
author Artem Serov <artem.serov@linaro.org> Thu Feb 15 14:43:48 2018 +0000
committer Artem Serov <artem.serov@linaro.org> Tue May 15 19:33:45 2018 +0100
tree 2573ba1024307763c54df655333f1e2477d0ea82
parent 9076eb66ad173933d7fbd5ce328d31c7f97fd202

ART: Enable scalar loop peeling and unrolling.

Turn on scalar loop peeling and unrolling by default.

Test: 482-checker-loop-back-edge-use, 530-checker-peel-unroll
Test: test-art-host, test-art-target, boot-to-gui
Change-Id: Ibfe1b54f790a97b281e85396da2985e0f22c2834

compiler/optimizing/loop_optimization.cc

diff --git a/compiler/optimizing/loop_optimization.cc b/compiler/optimizing/loop_optimization.cc
index 1ce3524..eda6bd1 100644
--- a/compiler/optimizing/loop_optimization.cc
+++ b/compiler/optimizing/loop_optimization.cc
@@ -33,9 +33,6 @@
 // Enables vectorization (SIMDization) in the loop optimizer.
 static constexpr bool kEnableVectorization = true;
 
-// Enables scalar loop unrolling in the loop optimizer.
-static constexpr bool kEnableScalarPeelingUnrolling = false;
-
 //
 // Static helpers.
 //
@@ -457,7 +454,7 @@
       vector_header_(nullptr),
       vector_body_(nullptr),
       vector_index_(nullptr),
-      arch_loop_helper_(ArchDefaultLoopHelper::Create(compiler_driver_ != nullptr
+      arch_loop_helper_(ArchNoOptsLoopHelper::Create(compiler_driver_ != nullptr
                                                           ? compiler_driver_->GetInstructionSet()
                                                           : InstructionSet::kNone,
                                                       global_allocator_)) {
@@ -761,7 +758,7 @@
 bool HLoopOptimization::TryUnrollingForBranchPenaltyReduction(LoopNode* node) {
   // Don't run peeling/unrolling if compiler_driver_ is nullptr (i.e., running under tests)
   // as InstructionSet is needed.
-  if (!kEnableScalarPeelingUnrolling || compiler_driver_ == nullptr) {
+  if (compiler_driver_ == nullptr) {
     return false;
   }
 
@@ -781,9 +778,9 @@
   LoopAnalysis::CalculateLoopBasicProperties(loop_info, &loop_analysis_info);
 
   // Check "IsLoopClonable" last as it can be time-consuming.
-  if (arch_loop_helper_->IsLoopTooBigForScalarPeelingUnrolling(&loop_analysis_info) ||
+  if (loop_analysis_info.HasInstructionsPreventingScalarUnrolling() ||
+      arch_loop_helper_->IsLoopNonBeneficialForScalarOpts(&loop_analysis_info) ||
       (loop_analysis_info.GetNumberOfExits() > 1) ||
-      loop_analysis_info.HasInstructionsPreventingScalarUnrolling() ||
       !PeelUnrollHelper::IsLoopClonable(loop_info)) {
     return false;
   }
@@ -807,7 +804,7 @@
 bool HLoopOptimization::TryPeelingForLoopInvariantExitsElimination(LoopNode* node) {
   // Don't run peeling/unrolling if compiler_driver_ is nullptr (i.e., running under tests)
   // as InstructionSet is needed.
-  if (!kEnableScalarPeelingUnrolling || compiler_driver_ == nullptr) {
+  if (compiler_driver_ == nullptr) {
     return false;
   }
 
@@ -821,8 +818,8 @@
   LoopAnalysis::CalculateLoopBasicProperties(loop_info, &loop_analysis_info);
 
   // Check "IsLoopClonable" last as it can be time-consuming.
-  if (arch_loop_helper_->IsLoopTooBigForScalarPeelingUnrolling(&loop_analysis_info) ||
-      loop_analysis_info.HasInstructionsPreventingScalarPeeling() ||
+  if (loop_analysis_info.HasInstructionsPreventingScalarPeeling() ||
+      arch_loop_helper_->IsLoopNonBeneficialForScalarOpts(&loop_analysis_info) ||
       !LoopAnalysis::HasLoopAtLeastOneInvariantExit(loop_info) ||
       !PeelUnrollHelper::IsLoopClonable(loop_info)) {
     return false;