[turbofan] First version of loop peeling.

src/compiler/pipeline.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/pipeline.h"
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
 
 #include "src/base/platform/elapsed-timer.h"
 #include "src/compiler/ast-graph-builder.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/basic-block-instrumentor.h"
 #include "src/compiler/change-lowering.h"
 #include "src/compiler/code-generator.h"
 #include "src/compiler/common-operator-reducer.h"
 #include "src/compiler/control-reducer.h"
 #include "src/compiler/graph-replay.h"
 #include "src/compiler/graph-visualizer.h"
 #include "src/compiler/instruction.h"
 #include "src/compiler/instruction-selector.h"
 #include "src/compiler/js-builtin-reducer.h"
 #include "src/compiler/js-context-specialization.h"
 #include "src/compiler/js-generic-lowering.h"
 #include "src/compiler/js-inlining.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/jump-threading.h"
 #include "src/compiler/load-elimination.h"
+#include "src/compiler/loop-analysis.h"
+#include "src/compiler/loop-peeling.h"
 #include "src/compiler/machine-operator-reducer.h"
 #include "src/compiler/move-optimizer.h"
 #include "src/compiler/osr.h"
 #include "src/compiler/pipeline-statistics.h"
 #include "src/compiler/register-allocator.h"
 #include "src/compiler/register-allocator-verifier.h"
 #include "src/compiler/schedule.h"
 #include "src/compiler/scheduler.h"
 #include "src/compiler/select-lowering.h"
 #include "src/compiler/simplified-lowering.h"
@@ skipping 466 matching lines @@
 struct EarlyControlReductionPhase : ControlReductionPhase {
   static const char* phase_name() { return "early control reduction"; }
 };
 
 
 struct LateControlReductionPhase : ControlReductionPhase {
   static const char* phase_name() { return "late control reduction"; }
 };
 
 
+struct StressLoopPeelingPhase {
+  static const char* phase_name() { return "stress loop peeling"; }
+
+  void Run(PipelineData* data, Zone* temp_zone) {
+    SourcePositionTable::Scope pos(data->source_positions(),
+                                   SourcePosition::Unknown());
+    // Peel the first outer loop for testing.
+    // TODO(titzer): peel all loops? the N'th loop? Innermost loops?
+    LoopTree* loop_tree = LoopFinder::BuildLoopTree(data->graph(), temp_zone);
+    if (loop_tree != NULL && loop_tree->outer_loops().size() > 0) {
+      LoopPeeler::Peel(data->graph(), data->common(), loop_tree,
+                       loop_tree->outer_loops()[0], temp_zone);
+    }
+  }
+};
+
+
 struct GenericLoweringPhase {
   static const char* phase_name() { return "generic lowering"; }
 
   void Run(PipelineData* data, Zone* temp_zone) {
     SourcePositionTable::Scope pos(data->source_positions(),
                                    SourcePosition::Unknown());
     JSGenericLowering generic(data->info(), data->jsgraph());
     SelectLowering select(data->jsgraph()->graph(), data->jsgraph()->common());
     GraphReducer graph_reducer(data->graph(), temp_zone);
     graph_reducer.AddReducer(&generic);
@@ skipping 308 matching lines @@
     RunPrintAndVerify("Typed");
   }
 
   BeginPhaseKind("lowering");
 
   if (info()->is_typing_enabled()) {
     // Lower JSOperators where we can determine types.
     Run<TypedLoweringPhase>();
     RunPrintAndVerify("Lowered typed");
 
+    if (FLAG_stress_loop_peeling) {
+      Run<StressLoopPeelingPhase>();
+      RunPrintAndVerify("Loop peeled", true);
+    }
+
     if (info()->is_osr()) {
       Run<OsrDeconstructionPhase>();
       RunPrintAndVerify("OSR deconstruction");
     }
 
     // Lower simplified operators and insert changes.
     Run<SimplifiedLoweringPhase>();
     RunPrintAndVerify("Lowered simplified");
 
     // Lower changes that have been inserted before.
@@ skipping 242 matching lines @@
 }
 
 
 void Pipeline::TearDown() {
   InstructionOperand::TearDownCaches();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8