AOT: Enable branch merging for checked smi comparisons

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 1739 matching lines @@
       case Token::kBIT_OR:
       case Token::kBIT_XOR:
         replacement =
             new BinarySmiOpInstr(op_kind(),
                                  new Value(left()->definition()),
                                  new Value(right()->definition()),
                                  Thread::kNoDeoptId);
       default:
         break;
     }
-    if (Token::IsRelationalOperator(op_kind())) {
-      replacement = new RelationalOpInstr(token_pos(), op_kind(),
+  }
+  return this;
+}
+
+
+ComparisonInstr* CheckedSmiComparisonInstr::CopyWithNewOperands(
+    Value* left, Value* right) {
+  UNREACHABLE();
+  return NULL;
+}
+
+
+Definition* CheckedSmiComparisonInstr::Canonicalize(FlowGraph* flow_graph) {
+  if ((left()->Type()->ToCid() == kSmiCid) &&
+      (right()->Type()->ToCid() == kSmiCid)) {
+    Definition* replacement = NULL;
+    if (Token::IsRelationalOperator(kind())) {
+      replacement = new RelationalOpInstr(token_pos(), kind(),
                                           new Value(left()->definition()),
                                           new Value(right()->definition()),
                                           kSmiCid,
                                           Thread::kNoDeoptId);
-    } else if (Token::IsEqualityOperator(op_kind())) {
-      replacement = new EqualityCompareInstr(token_pos(), op_kind(),
+    } else if (Token::IsEqualityOperator(kind())) {
+      replacement = new EqualityCompareInstr(token_pos(), kind(),
                                              new Value(left()->definition()),
                                              new Value(right()->definition()),
                                              kSmiCid,
                                              Thread::kNoDeoptId);
     }
     if (replacement != NULL) {
       flow_graph->InsertBefore(this, replacement, env(), FlowGraph::kValue);
       return replacement;
     }
   }
@@ skipping 571 matching lines @@
                              FlowGraph::kValue);
     return replacement;
   }
 
   return this;
 }
 
 
 Definition* BooleanNegateInstr::Canonicalize(FlowGraph* flow_graph) {
   Definition* defn = value()->definition();
-  if (defn->IsComparison() && defn->HasOnlyUse(value())) {
-    // Comparisons always have a bool result.
-    ASSERT(value()->definition()->Type()->ToCid() == kBoolCid);
+  if (defn->IsComparison() &&
+      defn->HasOnlyUse(value()) &&
+      defn->Type()->ToCid() == kBoolCid) {
     defn->AsComparison()->NegateComparison();
     return defn;
   }
   return this;
 }
 
 
 static bool MayBeBoxableNumber(intptr_t cid) {
   return (cid == kDynamicCid) ||
          (cid == kMintCid) ||
          (cid == kBigintCid) ||
          (cid == kDoubleCid);
 }
 
 
 static bool MaybeNumber(CompileType* type) {
   ASSERT(Type::Handle(Type::Number()).IsMoreSpecificThan(
              Type::Handle(Type::Number()), NULL, NULL, Heap::kOld));
   return type->ToAbstractType()->IsDynamicType()
       || type->ToAbstractType()->IsObjectType()
       || type->ToAbstractType()->IsTypeParameter()
       || type->IsMoreSpecificThan(Type::Handle(Type::Number()));
 }
 
 
 // Returns a replacement for a strict comparison and signals if the result has
 // to be negated.
 static Definition* CanonicalizeStrictCompare(StrictCompareInstr* compare,
-                                             bool* negated) {
+                                             bool* negated,
+                                             bool is_branch) {
   // Use propagated cid and type information to eliminate number checks.
   // If one of the inputs is not a boxable number (Mint, Double, Bigint), or
   // is not a subtype of num, no need for number checks.
   if (compare->needs_number_check()) {
     if (!MayBeBoxableNumber(compare->left()->Type()->ToCid()) ||
         !MayBeBoxableNumber(compare->right()->Type()->ToCid()))  {
       compare->set_needs_number_check(false);
     } else if (!MaybeNumber(compare->left()->Type()) ||
                !MaybeNumber(compare->right()->Type())) {
       compare->set_needs_number_check(false);
     }
   }
-
   *negated = false;
   PassiveObject& constant = PassiveObject::Handle();
   Value* other = NULL;
   if (compare->right()->BindsToConstant()) {
     constant = compare->right()->BoundConstant().raw();
     other = compare->left();
   } else if (compare->left()->BindsToConstant()) {
     constant = compare->left()->BoundConstant().raw();
     other = compare->right();
   } else {
     return compare;
   }
 
+  const bool can_merge = is_branch || (other->Type()->ToCid() == kBoolCid);
   Definition* other_defn = other->definition();
   Token::Kind kind = compare->kind();
   // Handle e === true.
   if ((kind == Token::kEQ_STRICT) &&
       (constant.raw() == Bool::True().raw()) &&
-      (other->Type()->ToCid() == kBoolCid)) {
+      can_merge) {
     return other_defn;
   }
   // Handle e !== false.
   if ((kind == Token::kNE_STRICT) &&
       (constant.raw() == Bool::False().raw()) &&
-      (other->Type()->ToCid() == kBoolCid)) {
+      can_merge) {
     return other_defn;
   }
   // Handle e !== true.
   if ((kind == Token::kNE_STRICT) &&
       (constant.raw() == Bool::True().raw()) &&
       other_defn->IsComparison() &&
-      (other->Type()->ToCid() == kBoolCid) &&
+      can_merge &&
       other_defn->HasOnlyUse(other)) {
     *negated = true;
     return other_defn;
   }
   // Handle e === false.
   if ((kind == Token::kEQ_STRICT) &&
       (constant.raw() == Bool::False().raw()) &&
       other_defn->IsComparison() &&
-      (other->Type()->ToCid() == kBoolCid) &&
+      can_merge &&
       other_defn->HasOnlyUse(other)) {
     *negated = true;
     return other_defn;
   }
   return compare;
 }
 
 
 static bool BindsToGivenConstant(Value* v, intptr_t expected) {
   return v->BindsToConstant() &&
@@ skipping 39 matching lines @@
   return false;
 }
 
 
 Instruction* BranchInstr::Canonicalize(FlowGraph* flow_graph) {
   Zone* zone = flow_graph->zone();
   // Only handle strict-compares.
   if (comparison()->IsStrictCompare()) {
     bool negated = false;
     Definition* replacement =
-        CanonicalizeStrictCompare(comparison()->AsStrictCompare(), &negated);
+        CanonicalizeStrictCompare(comparison()->AsStrictCompare(),
+                                  &negated, /* is_branch = */ true);
     if (replacement == comparison()) {
       return this;
     }
     ComparisonInstr* comp = replacement->AsComparison();
     if ((comp == NULL) ||
         comp->CanDeoptimize() ||
         comp->HasUnmatchedInputRepresentations()) {
       return this;
     }
 
@@ skipping 51 matching lines @@
       bit_and->RemoveFromGraph();
     }
   }
   return this;
 }
 
 
 Definition* StrictCompareInstr::Canonicalize(FlowGraph* flow_graph) {
   if (!HasUses()) return NULL;
   bool negated = false;
-  Definition* replacement = CanonicalizeStrictCompare(this, &negated);
+  Definition* replacement = CanonicalizeStrictCompare(this, &negated,
+                                                      /* is_branch = */ false);
   if (negated && replacement->IsComparison()) {
     ASSERT(replacement != this);
     replacement->AsComparison()->NegateComparison();
   }
   return replacement;
 }
 
 
 Instruction* CheckClassInstr::Canonicalize(FlowGraph* flow_graph) {
   const intptr_t value_cid = value()->Type()->ToCid();
@@ skipping 1349 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