ICData::NumberOfChecks is O(n) so don't call it in loops

runtime/vm/intermediate_language.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/bootstrap.h"
 #include "vm/compiler.h"
 #include "vm/constant_propagator.h"
@@ skipping 142 matching lines @@
                                  TokenPosition token_pos)
     : TemplateInstruction(deopt_id),
       unary_checks_(unary_checks),
       cids_(unary_checks.NumberOfChecks()),
       licm_hoisted_(false),
       is_dense_switch_(IsDenseCidRange(unary_checks)),
       token_pos_(token_pos) {
   ASSERT(unary_checks.IsZoneHandle());
   // Expected useful check data.
   ASSERT(!unary_checks_.IsNull());
-  ASSERT(unary_checks_.NumberOfChecks() > 0);
+  const intptr_t number_of_checks = unary_checks_.NumberOfChecks();
+  ASSERT(number_of_checks > 0);
   ASSERT(unary_checks_.NumArgsTested() == 1);
   SetInputAt(0, value);
   // Otherwise use CheckSmiInstr.
-  ASSERT((unary_checks_.NumberOfChecks() != 1) ||
+  ASSERT(number_of_checks != 1 ||
          (unary_checks_.GetReceiverClassIdAt(0) != kSmiCid));
-  for (intptr_t i = 0; i < unary_checks.NumberOfChecks(); ++i) {
+  for (intptr_t i = 0; i < number_of_checks; ++i) {
     cids_.Add(unary_checks.GetReceiverClassIdAt(i));
   }
   cids_.Sort(LowestFirst);
 }
 
 
 bool CheckClassInstr::AttributesEqual(Instruction* other) const {
   CheckClassInstr* other_check = other->AsCheckClass();
   ASSERT(other_check != NULL);
-  if (unary_checks().NumberOfChecks() !=
-      other_check->unary_checks().NumberOfChecks()) {
+  const intptr_t number_of_checks = unary_checks_.NumberOfChecks();
+  if (number_of_checks != other_check->unary_checks().NumberOfChecks()) {
     return false;
   }
-  for (intptr_t i = 0; i < unary_checks().NumberOfChecks(); ++i) {
+  for (intptr_t i = 0; i < number_of_checks; ++i) {
     // TODO(fschneider): Make sure ic_data are sorted to hit more cases.
     if (unary_checks().GetReceiverClassIdAt(i) !=
         other_check->unary_checks().GetReceiverClassIdAt(i)) {
       return false;
     }
   }
   return true;
 }
 
 
@@ skipping 18 matching lines @@
 
 
 EffectSet CheckClassIdInstr::Dependencies() const {
   // Externalization of strings via the API can change the class-id.
   return Field::IsExternalizableCid(cid_) ? EffectSet::Externalization()
                                           : EffectSet::None();
 }
 
 
 bool CheckClassInstr::DeoptIfNull() const {
-  if (unary_checks().NumberOfChecks() != 1) {
+  if (!unary_checks().NumberOfChecksIs(1)) {
     return false;
   }
   CompileType* in_type = value()->Type();
   const intptr_t cid = unary_checks().GetCidAt(0);
   // Performance check: use CheckSmiInstr instead.
   ASSERT(cid != kSmiCid);
   return in_type->is_nullable() && (in_type->ToNullableCid() == cid);
 }
 
 
 // Null object is a singleton of null-class (except for some sentinel,
 // transitional temporaries). Instead of checking against the null class only
 // we can check against null instance instead.
 bool CheckClassInstr::DeoptIfNotNull() const {
-  if (unary_checks().NumberOfChecks() != 1) {
+  if (!unary_checks().NumberOfChecksIs(1)) {
     return false;
   }
   const intptr_t cid = unary_checks().GetCidAt(0);
   return cid == kNullCid;
 }
 
 
 bool CheckClassInstr::IsDenseCidRange(const ICData& unary_checks) {
   ASSERT(unary_checks.NumArgsTested() == 1);
   // TODO(fschneider): Support smis in dense cid checks.
   if (unary_checks.GetReceiverClassIdAt(0) == kSmiCid) return false;
-  if (unary_checks.NumberOfChecks() <= 2) return false;
+  const intptr_t number_of_checks = unary_checks.NumberOfChecks();
+  if (number_of_checks <= 2) return false;
   intptr_t max = 0;
   intptr_t min = kIntptrMax;
-  for (intptr_t i = 0; i < unary_checks.NumberOfChecks(); ++i) {
+  for (intptr_t i = 0; i < number_of_checks; ++i) {
     intptr_t cid = unary_checks.GetCidAt(i);
     if (cid < min) min = cid;
     if (cid > max) max = cid;
   }
   return (max - min) < kBitsPerWord;
 }
 
 
 bool CheckClassInstr::IsDenseSwitch() const {
   return is_dense_switch_;
@@ skipping 3695 matching lines @@
   set_native_c_function(native_function);
   function().SetIsNativeAutoSetupScope(auto_setup_scope);
   Dart_NativeEntryResolver resolver = library.native_entry_resolver();
   bool is_bootstrap_native = Bootstrap::IsBootstapResolver(resolver);
   set_is_bootstrap_native(is_bootstrap_native);
 }
 
 #undef __
 
 }  // namespace dart