Use AssumeRepresentation when the representation is known and will not change.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index f50a2d5796c3880b0a3a0fc3d4b4d3e327d690da..d37daccccf5162dba29d25b2b5999175b0dcd2e7 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -723,7 +723,7 @@ HInstruction* HGraphBuilder::IfBuilder::IfCompare(
       new(zone()) HCompareIDAndBranch(left, right, token);
   compare->set_observed_input_representation(input_representation,
                                              input_representation);
-  compare->ChangeRepresentation(input_representation);
+  compare->AssumeRepresentation(input_representation);
   AddCompare(compare);
   return compare;
 }
@@ -905,7 +905,7 @@ HValue* HGraphBuilder::LoopBuilder::BeginBody(
   phi_ = new(zone()) HPhi(env->values()->length(), zone());
   header_block_->AddPhi(phi_);
   phi_->AddInput(initial);
-  phi_->ChangeRepresentation(Representation::Integer32());
+  phi_->AssumeRepresentation(Representation::Integer32());
   env->Push(initial);
   builder_->current_block()->GotoNoSimulate(header_block_);
 
@@ -921,7 +921,7 @@ HValue* HGraphBuilder::LoopBuilder::BeginBody(
       new(zone()) HCompareIDAndBranch(phi_, terminating, token);
   compare->set_observed_input_representation(input_representation,
                                              input_representation);
-  compare->ChangeRepresentation(input_representation);
+  compare->AssumeRepresentation(input_representation);
   compare->SetSuccessorAt(0, body_block_);
   compare->SetSuccessorAt(1, exit_block_);
   builder_->current_block()->Finish(compare);
@@ -935,7 +935,7 @@ HValue* HGraphBuilder::LoopBuilder::BeginBody(
       increment_ = HSub::New(zone(), context_, phi_, one);
     }
     increment_->ClearFlag(HValue::kCanOverflow);
-    increment_->ChangeRepresentation(Representation::Integer32());
+    increment_->AssumeRepresentation(Representation::Integer32());
     builder_->AddInstruction(increment_);
     return increment_;
   } else {
@@ -955,7 +955,7 @@ void HGraphBuilder::LoopBuilder::EndBody() {
       increment_ = HSub::New(zone(), context_, phi_, one);
     }
     increment_->ClearFlag(HValue::kCanOverflow);
-    increment_->ChangeRepresentation(Representation::Integer32());
+    increment_->AssumeRepresentation(Representation::Integer32());
     builder_->AddInstruction(increment_);
   }
 
@@ -1188,7 +1188,7 @@ HValue* HGraphBuilder::BuildCheckForCapacityGrow(HValue* object,
   if (is_js_array) {
     HValue* new_length = AddInstruction(
         HAdd::New(zone, context, length, graph_->GetConstant1()));
-    new_length->ChangeRepresentation(Representation::Integer32());
+    new_length->AssumeRepresentation(Representation::Integer32());
     new_length->ClearFlag(HValue::kCanOverflow);
 
     Factory* factory = isolate()->factory();
@@ -1374,7 +1374,7 @@ HValue* HGraphBuilder::BuildAllocateElements(HValue* context,
   AddInstruction(elements_size_value);
   HValue* mul = AddInstruction(
                     HMul::New(zone, context, capacity, elements_size_value));
-  mul->ChangeRepresentation(Representation::Integer32());
+  mul->AssumeRepresentation(Representation::Integer32());
   mul->ClearFlag(HValue::kCanOverflow);
 
   HConstant* header_size =
@@ -1382,7 +1382,7 @@ HValue* HGraphBuilder::BuildAllocateElements(HValue* context,
   AddInstruction(header_size);
   HValue* total_size = AddInstruction(
                            HAdd::New(zone, context, mul, header_size));
-  total_size->ChangeRepresentation(Representation::Integer32());
+  total_size->AssumeRepresentation(Representation::Integer32());
   total_size->ClearFlag(HValue::kCanOverflow);
 
   HAllocate::Flags flags = HAllocate::DefaultFlags(kind);
@@ -1538,12 +1538,12 @@ HValue* HGraphBuilder::BuildNewElementsCapacity(HValue* context,
   HValue* half_old_capacity =
       AddInstruction(HShr::New(zone, context, old_capacity,
                                graph_->GetConstant1()));
-  half_old_capacity->ChangeRepresentation(Representation::Integer32());
+  half_old_capacity->AssumeRepresentation(Representation::Integer32());
   half_old_capacity->ClearFlag(HValue::kCanOverflow);
 
   HValue* new_capacity = AddInstruction(
       HAdd::New(zone, context, half_old_capacity, old_capacity));
-  new_capacity->ChangeRepresentation(Representation::Integer32());
+  new_capacity->AssumeRepresentation(Representation::Integer32());
   new_capacity->ClearFlag(HValue::kCanOverflow);
 
   HValue* min_growth =
@@ -1551,7 +1551,7 @@ HValue* HGraphBuilder::BuildNewElementsCapacity(HValue* context,
 
   new_capacity = AddInstruction(
       HAdd::New(zone, context, new_capacity, min_growth));
-  new_capacity->ChangeRepresentation(Representation::Integer32());
+  new_capacity->AssumeRepresentation(Representation::Integer32());
   new_capacity->ClearFlag(HValue::kCanOverflow);
 
   return new_capacity;
@@ -1931,7 +1931,7 @@ HValue* HGraphBuilder::JSArrayBuilder::EstablishAllocationSize(
   AddInstruction(elements_size_value);
   HInstruction* mul = HMul::New(zone(), context, length_node,
                                 elements_size_value);
-  mul->ChangeRepresentation(Representation::Integer32());
+  mul->AssumeRepresentation(Representation::Integer32());
   mul->ClearFlag(HValue::kCanOverflow);
   AddInstruction(mul);
 
@@ -1939,7 +1939,7 @@ HValue* HGraphBuilder::JSArrayBuilder::EstablishAllocationSize(
                                              Representation::Integer32());
   AddInstruction(base);
   HInstruction* total_size = HAdd::New(zone(), context, base, mul);
-  total_size->ChangeRepresentation(Representation::Integer32());
+  total_size->AssumeRepresentation(Representation::Integer32());
   total_size->ClearFlag(HValue::kCanOverflow);
   AddInstruction(total_size);
   return total_size;