[turbofan] Remove the unused loop peeling stress option.

Review-Url: https://codereview.chromium.org/2570803002
Cr-Commit-Position: refs/heads/master@{#41675}

src/compiler/pipeline.cc

@@ -1173,21 +1173,6 @@ struct LateGraphTrimmingPhase {
 };
 
 
-struct StressLoopPeelingPhase {
-  static const char* phase_name() { return "stress loop peeling"; }
-
-  void Run(PipelineData* data, Zone* temp_zone) {
-    // 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 != nullptr && loop_tree->outer_loops().size() > 0) {
-      LoopPeeler::Peel(data->graph(), data->common(), loop_tree,
-                       loop_tree->outer_loops()[0], temp_zone);
-    }
-  }
-};
-
-
 struct ComputeSchedulePhase {
   static const char* phase_name() { return "scheduling"; }
 
@@ -1533,11 +1518,6 @@ bool PipelineImpl::CreateGraph() {
       RunPrintAndVerify("Loop exits eliminated", true);
     }
 
-    if (FLAG_turbo_stress_loop_peeling) {
-      Run<StressLoopPeelingPhase>();
-      RunPrintAndVerify("Loop peeled");
-    }
-
     if (!info()->shared_info()->asm_function()) {
       if (FLAG_turbo_load_elimination) {
         Run<LoadEliminationPhase>();

src/flag-definitions.h

@@ -460,8 +460,6 @@ DEFINE_BOOL(turbo_verify_allocation, DEBUG_BOOL,
             "verify register allocation in TurboFan")
 DEFINE_BOOL(turbo_move_optimization, true, "optimize gap moves in TurboFan")
 DEFINE_BOOL(turbo_jt, true, "enable jump threading in TurboFan")
-DEFINE_BOOL(turbo_stress_loop_peeling, false,
-            "stress loop peeling optimization")
 DEFINE_BOOL(turbo_loop_peeling, true, "Turbofan loop peeling")
 DEFINE_BOOL(turbo_loop_variable, true, "Turbofan loop variable optimization")
 DEFINE_BOOL(turbo_cf_optimization, true, "optimize control flow in TurboFan")