Mark HChange that convert to int32 with truncation with the appropiate flag.

Before we would compute the flag by iterating over all uses. The truncating
flag is always determined at construction time since we already computed
the flag for all other instructions before inserting HChange instructions.

Review URL: http://codereview.chromium.org/6615012

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7047 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 22916f5..371bc4a 100644 (file)
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -940,13 +940,14 @@ class HChange: public HUnaryOperation {
  public:
   HChange(HValue* value,
           Representation from,
-          Representation to)
+          Representation to,
+          bool is_truncating)
       : HUnaryOperation(value), from_(from), to_(to) {
     ASSERT(!from.IsNone() && !to.IsNone());
     ASSERT(!from.Equals(to));
     set_representation(to);
     SetFlag(kUseGVN);
-
+    if (is_truncating) SetFlag(kTruncatingToInt32);
     if (from.IsInteger32() && to.IsTagged() && value->range() != NULL &&
         value->range()->IsInSmiRange()) {
       set_type(HType::Smi());
@@ -961,12 +962,7 @@ class HChange: public HUnaryOperation {
     return from_;
   }
 
-  bool CanTruncateToInt32() const {
-    for (int i = 0; i < uses()->length(); ++i) {
-      if (!uses()->at(i)->CheckFlag(HValue::kTruncatingToInt32)) return false;
-    }
-    return true;
-  }
+  bool CanTruncateToInt32() const { return CheckFlag(kTruncatingToInt32); }
 
   virtual void PrintDataTo(StringStream* stream);
 
@@ -978,8 +974,7 @@ class HChange: public HUnaryOperation {
     if (!other->IsChange()) return false;
     HChange* change = HChange::cast(other);
     return value() == change->value()
-        && to().Equals(change->to())
-        && CanTruncateToInt32() == change->CanTruncateToInt32();
+        && to().Equals(change->to());
   }
 
  private:

diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 30cc088..50ab7b2 100644 (file)
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -1663,8 +1663,7 @@ void HGraph::PropagateMinusZeroChecks(HValue* value, BitVector* visited) {
 
 void HGraph::InsertRepresentationChangeForUse(HValue* value,
                                               HValue* use,
-                                              Representation to,
-                                              bool is_truncating) {
+                                              Representation to) {
   // Insert the representation change right before its use. For phi-uses we
   // insert at the end of the corresponding predecessor.
   HInstruction* next = NULL;
@@ -1681,6 +1680,7 @@ void HGraph::InsertRepresentationChangeForUse(HValue* value,
   // information we treat constants like normal instructions and insert the
   // change instructions for them.
   HInstruction* new_value = NULL;
+  bool is_truncating = use->CheckFlag(HValue::kTruncatingToInt32);
   if (value->IsConstant()) {
     HConstant* constant = HConstant::cast(value);
     // Try to create a new copy of the constant with the new representation.
@@ -1690,7 +1690,7 @@ void HGraph::InsertRepresentationChangeForUse(HValue* value,
   }
 
   if (new_value == NULL) {
-    new_value = new HChange(value, value->representation(), to);
+    new_value = new HChange(value, value->representation(), to, is_truncating);
   }
 
   new_value->InsertBefore(next);
@@ -1765,8 +1765,7 @@ void HGraph::InsertRepresentationChanges(HValue* current) {
   for (int i = 0; i < to_convert.length(); ++i) {
     HValue* use = to_convert[i];
     Representation r_to = to_convert_reps[i];
-    bool is_truncating = use->CheckFlag(HValue::kTruncatingToInt32);
-    InsertRepresentationChangeForUse(current, use, r_to, is_truncating);
+    InsertRepresentationChangeForUse(current, use, r_to);
   }
 
   if (current->uses()->is_empty()) {

diff --git a/src/hydrogen.h b/src/hydrogen.h
index 185d2cb..9bb3f8c 100644 (file)
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -302,8 +302,7 @@ class HGraph: public HSubgraph {
   void PropagateMinusZeroChecks(HValue* value, BitVector* visited);
   void InsertRepresentationChangeForUse(HValue* value,
                                         HValue* use,
-                                        Representation to,
-                                        bool truncating);
+                                        Representation to);
   void InsertRepresentationChanges(HValue* current);
   void InferTypes(ZoneList<HValue*>* worklist);
   void InitializeInferredTypes(int from_inclusive, int to_inclusive);