[turbofan] Generate loop exits in the bytecode graph builder.

src/compiler/code-generator.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/code-generator.h"
 
 #include "src/address-map.h"
 #include "src/base/adapters.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/linkage.h"
@@ skipping 843 matching lines @@
     } else {
       DCHECK_EQ(MachineRepresentation::kFloat32, type.representation());
       translation->StoreFloatRegister(converter.ToFloatRegister(op));
     }
   } else if (op->IsImmediate()) {
     InstructionOperandConverter converter(this, instr);
     Constant constant = converter.ToConstant(op);
     Handle<Object> constant_object;
     switch (constant.type()) {
       case Constant::kInt32:
-        DCHECK(type == MachineType::Int32() || type == MachineType::Uint32() ||
-               type.representation() == MachineRepresentation::kBit ||
-               type.representation() == MachineRepresentation::kNone);
-        DCHECK(type.representation() != MachineRepresentation::kNone ||
-               constant.ToInt32() == FrameStateDescriptor::kImpossibleValue);
+        if (type.representation() == MachineRepresentation::kTagged) {
+          // When pointers are 4 bytes, we can use int32 constants to represent
+          // Smis.
+          DCHECK_EQ(4, kPointerSize);
+          constant_object =
+              handle(reinterpret_cast<Smi*>(constant.ToInt32()), isolate());
+          DCHECK(constant_object->IsSmi());
+        } else {
+          DCHECK(type == MachineType::Int32() ||
+                 type == MachineType::Uint32() ||
+                 type.representation() == MachineRepresentation::kBit ||
+                 type.representation() == MachineRepresentation::kNone);
+          DCHECK(type.representation() != MachineRepresentation::kNone ||
+                 constant.ToInt32() == FrameStateDescriptor::kImpossibleValue);
 
+          constant_object =
+              isolate()->factory()->NewNumberFromInt(constant.ToInt32());
+        }
+        break;
+      case Constant::kInt64:
+        // When pointers are 8 bytes, we can use int64 constants to represent
+        // Smis.
+        DCHECK_EQ(type.representation(), MachineRepresentation::kTagged);
+        DCHECK_EQ(8, kPointerSize);
         constant_object =
-            isolate()->factory()->NewNumberFromInt(constant.ToInt32());
+            handle(reinterpret_cast<Smi*>(constant.ToInt64()), isolate());
+        DCHECK(constant_object->IsSmi());
         break;
       case Constant::kFloat32:
         DCHECK(type.representation() == MachineRepresentation::kFloat32 ||
                type.representation() == MachineRepresentation::kTagged);
         constant_object = isolate()->factory()->NewNumber(constant.ToFloat32());
         break;
       case Constant::kFloat64:
         DCHECK(type.representation() == MachineRepresentation::kFloat64 ||
                type.representation() == MachineRepresentation::kTagged);
         constant_object = isolate()->factory()->NewNumber(constant.ToFloat64());
@@ skipping 35 matching lines @@
     : frame_(gen->frame()), masm_(gen->masm()), next_(gen->ools_) {
   gen->ools_ = this;
 }
 
 
 OutOfLineCode::~OutOfLineCode() {}
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8