Turn stack check elimination into proper HPhase.

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 22 matching lines @@
 #include "codegen.h"
 #include "full-codegen.h"
 #include "hashmap.h"
 #include "hydrogen-dce.h"
 #include "hydrogen-environment-liveness.h"
 #include "hydrogen-escape-analysis.h"
 #include "hydrogen-infer-representation.h"
 #include "hydrogen-gvn.h"
 #include "hydrogen-osr.h"
 #include "hydrogen-range-analysis.h"
+#include "hydrogen-sce.h"
 #include "hydrogen-uint32-analysis.h"
 #include "lithium-allocator.h"
 #include "parser.h"
 #include "scopeinfo.h"
 #include "scopes.h"
 #include "stub-cache.h"
 #include "typing.h"
 
 #if V8_TARGET_ARCH_IA32
 #include "ia32/lithium-codegen-ia32.h"
@@ skipping 2572 matching lines @@
         if (!in_worklist.Contains(use->id())) {
           in_worklist.Add(use->id());
           worklist->Add(use, zone());
         }
       }
     }
   }
 }
 
 
-class HStackCheckEliminator BASE_EMBEDDED {
- public:
-  explicit HStackCheckEliminator(HGraph* graph) : graph_(graph) { }
-
-  void Process();
-
- private:
-  HGraph* graph_;
-};
-
-
-void HStackCheckEliminator::Process() {
-  HPhase phase("H_Stack check elimination", graph_);
-  // For each loop block walk the dominator tree from the backwards branch to
-  // the loop header. If a call instruction is encountered the backwards branch
-  // is dominated by a call and the stack check in the backwards branch can be
-  // removed.
-  for (int i = 0; i < graph_->blocks()->length(); i++) {
-    HBasicBlock* block = graph_->blocks()->at(i);
-    if (block->IsLoopHeader()) {
-      HBasicBlock* back_edge = block->loop_information()->GetLastBackEdge();
-      HBasicBlock* dominator = back_edge;
-      while (true) {
-        for (HInstructionIterator it(dominator); !it.Done(); it.Advance()) {
-          if (it.Current()->IsCall()) {
-            block->loop_information()->stack_check()->Eliminate();
-            break;
-          }
-        }
-
-        // Done when the loop header is processed.
-        if (dominator == block) break;
-
-        // Move up the dominator tree.
-        dominator = dominator->dominator();
-      }
-    }
-  }
-}
-
-
 void HGraph::MergeRemovableSimulates() {
   HPhase phase("H_Merge removable simulates", this);
   ZoneList<HSimulate*> mergelist(2, zone());
   for (int i = 0; i < blocks()->length(); ++i) {
     HBasicBlock* block = blocks()->at(i);
     // Make sure the merge list is empty at the start of a block.
     ASSERT(mergelist.is_empty());
     // Nasty heuristic: Never remove the first simulate in a block. This
     // just so happens to have a beneficial effect on register allocation.
     bool first = true;
@@ skipping 805 matching lines @@
 
   if (FLAG_use_escape_analysis) Run<HEscapeAnalysisPhase>();
 
   if (FLAG_use_gvn) Run<HGlobalValueNumberingPhase>();
 
   if (FLAG_use_range) Run<HRangeAnalysisPhase>();
 
   ComputeMinusZeroChecks();
 
   // Eliminate redundant stack checks on backwards branches.
-  HStackCheckEliminator sce(this);
-  sce.Process();
+  Run<HStackCheckEliminationPhase>();
 
   if (FLAG_idefs) SetupInformativeDefinitions();
   if (FLAG_array_bounds_checks_elimination && !FLAG_idefs) {
     EliminateRedundantBoundsChecks();
   }
   if (FLAG_array_index_dehoisting) DehoistSimpleArrayIndexComputations();
   if (FLAG_dead_code_elimination) Run<HDeadCodeEliminationPhase>();
 
   RestoreActualValues();
 
@@ skipping 7228 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal