1 files changed, 34 insertions, 22 deletions

diff --git a/compiler/optimizing/loop_analysis.cc b/compiler/optimizing/loop_analysis.cc
index a2124455e2..efb23e7d3e 100644
--- a/compiler/optimizing/loop_analysis.cc
+++ b/compiler/optimizing/loop_analysis.cc
@@ -17,19 +17,34 @@
 #include "loop_analysis.h"
 
 #include "base/bit_vector-inl.h"
+#include "induction_var_range.h"
 
 namespace art {
 
 void LoopAnalysis::CalculateLoopBasicProperties(HLoopInformation* loop_info,
-                                                LoopAnalysisInfo* analysis_results) {
+                                                LoopAnalysisInfo* analysis_results,
+                                                int64_t trip_count) {
+  analysis_results->trip_count_ = trip_count;
+
   for (HBlocksInLoopIterator block_it(*loop_info);
        !block_it.Done();
        block_it.Advance()) {
     HBasicBlock* block = block_it.Current();
 
+    // Check whether one of the successor is loop exit.
     for (HBasicBlock* successor : block->GetSuccessors()) {
       if (!loop_info->Contains(*successor)) {
         analysis_results->exits_num_++;
+
+        // We track number of invariant loop exits which correspond to HIf instruction and
+        // can be eliminated by loop peeling; other control flow instruction are ignored and will
+        // not cause loop peeling to happen as they either cannot be inside a loop, or by
+        // definition cannot be loop exits (unconditional instructions), or are not beneficial for
+        // the optimization.
+        HIf* hif = block->GetLastInstruction()->AsIf();
+        if (hif != nullptr && !loop_info->Contains(*hif->InputAt(0)->GetBlock())) {
+          analysis_results->invariant_exits_num_++;
+        }
       }
     }
 
@@ -48,20 +63,13 @@ void LoopAnalysis::CalculateLoopBasicProperties(HLoopInformation* loop_info,
   }
 }
 
-bool LoopAnalysis::HasLoopAtLeastOneInvariantExit(HLoopInformation* loop_info) {
-  HGraph* graph = loop_info->GetHeader()->GetGraph();
-  for (uint32_t block_id : loop_info->GetBlocks().Indexes()) {
-    HBasicBlock* block = graph->GetBlocks()[block_id];
-    DCHECK(block != nullptr);
-    if (block->EndsWithIf()) {
-      HIf* hif = block->GetLastInstruction()->AsIf();
-      HInstruction* input = hif->InputAt(0);
-      if (IsLoopExit(loop_info, hif) && !loop_info->Contains(*input->GetBlock())) {
-        return true;
-      }
-    }
+int64_t LoopAnalysis::GetLoopTripCount(HLoopInformation* loop_info,
+                                       const InductionVarRange* induction_range) {
+  int64_t trip_count;
+  if (!induction_range->HasKnownTripCount(loop_info, &trip_count)) {
+    trip_count = LoopAnalysisInfo::kUnknownTripCount;
   }
-  return false;
+  return trip_count;
 }
 
 // Default implementation of loop helper; used for all targets unless a custom implementation
@@ -77,18 +85,22 @@ class ArchDefaultLoopHelper : public ArchNoOptsLoopHelper {
   // Loop's maximum basic block count. Loops with higher count will not be peeled/unrolled.
   static constexpr uint32_t kScalarHeuristicMaxBodySizeBlocks = 6;
 
-  bool IsLoopNonBeneficialForScalarOpts(LoopAnalysisInfo* loop_analysis_info) const OVERRIDE {
-    return loop_analysis_info->HasLongTypeInstructions() ||
-           IsLoopTooBig(loop_analysis_info,
+  bool IsLoopNonBeneficialForScalarOpts(LoopAnalysisInfo* analysis_info) const OVERRIDE {
+    return analysis_info->HasLongTypeInstructions() ||
+           IsLoopTooBig(analysis_info,
                         kScalarHeuristicMaxBodySizeInstr,
                         kScalarHeuristicMaxBodySizeBlocks);
   }
 
-  uint32_t GetScalarUnrollingFactor(HLoopInformation* loop_info ATTRIBUTE_UNUSED,
-                                    uint64_t trip_count) const OVERRIDE {
+  uint32_t GetScalarUnrollingFactor(const LoopAnalysisInfo* analysis_info) const OVERRIDE {
+    int64_t trip_count = analysis_info->GetTripCount();
+    // Unroll only loops with known trip count.
+    if (trip_count == LoopAnalysisInfo::kUnknownTripCount) {
+      return LoopAnalysisInfo::kNoUnrollingFactor;
+    }
     uint32_t desired_unrolling_factor = kScalarMaxUnrollFactor;
     if (trip_count < desired_unrolling_factor || trip_count % desired_unrolling_factor != 0) {
-      return kNoUnrollingFactor;
+      return LoopAnalysisInfo::kNoUnrollingFactor;
     }
 
     return desired_unrolling_factor;
@@ -136,12 +148,12 @@ class Arm64LoopHelper : public ArchDefaultLoopHelper {
     // TODO: Unroll loops with unknown trip count.
     DCHECK_NE(vector_length, 0u);
     if (trip_count < (2 * vector_length + max_peel)) {
-      return kNoUnrollingFactor;
+      return LoopAnalysisInfo::kNoUnrollingFactor;
     }
     // Don't unroll for large loop body size.
     uint32_t instruction_count = block->GetInstructions().CountSize();
     if (instruction_count >= kArm64SimdHeuristicMaxBodySizeInstr) {
-      return kNoUnrollingFactor;
+      return LoopAnalysisInfo::kNoUnrollingFactor;
     }
     // Find a beneficial unroll factor with the following restrictions:
     //  - At least one iteration of the transformed loop should be executed.