Reapply r18377 it was reverted due to the unrelated bug it surfaced.

runtime/vm/intermediate_language_x64.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/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 201 matching lines @@
   // We should never return here.
   __ int3();
   __ Bind(&done);
 }
 
 
 void AssertBooleanInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   Register obj = locs()->in(0).reg();
   Register result = locs()->out().reg();
 
-  if (!is_eliminated()) {
-    EmitAssertBoolean(obj, token_pos(), deopt_id(), locs(), compiler);
-  }
+  EmitAssertBoolean(obj, token_pos(), deopt_id(), locs(), compiler);
   ASSERT(obj == result);
 }
 
 
 LocationSummary* ArgumentDefinitionTestInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;
   LocationSummary* locs =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kCall);
   locs->set_in(0, Location::RegisterLocation(RAX));
@@ skipping 719 matching lines @@
   Register result = locs()->out().reg();
   __ movq(result,
           Immediate(reinterpret_cast<uword>(Symbols::PredefinedAddress())));
   __ movq(result, Address(result,
                           char_code,
                           TIMES_HALF_WORD_SIZE,  // Char code is a smi.
                           Symbols::kNullCharCodeSymbolOffset * kWordSize));
 }
 
 
-intptr_t LoadIndexedInstr::ResultCid() const {
+CompileType* LoadIndexedInstr::ComputeInitialType() const {
   switch (class_id_) {
     case kArrayCid:
     case kImmutableArrayCid:
-      return kDynamicCid;
+      return CompileType::Dynamic();
+
     case kFloat32ArrayCid :
     case kFloat64ArrayCid :
-      return kDoubleCid;
+      return CompileType::FromCid(kDoubleCid);
+
     case kInt8ArrayCid:
     case kUint8ArrayCid:
     case kUint8ClampedArrayCid:
     case kExternalUint8ArrayCid:
     case kExternalUint8ClampedArrayCid:
     case kInt16ArrayCid:
     case kUint16ArrayCid:
     case kOneByteStringCid:
     case kTwoByteStringCid:
     case kInt32ArrayCid:
     case kUint32ArrayCid:
-      return kSmiCid;
+      return CompileType::FromCid(kSmiCid);
+
     default:
       UNIMPLEMENTED();
-      return kSmiCid;
+      return NULL;
   }
 }
 
 
 Representation LoadIndexedInstr::representation() const {
   switch (class_id_) {
     case kArrayCid:
     case kImmutableArrayCid:
     case kInt8ArrayCid:
     case kUint8ArrayCid:
@@ skipping 1123 matching lines @@
       break;
     }
     default:
       UNREACHABLE();
       break;
   }
 }
 
 
 LocationSummary* CheckEitherNonSmiInstr::MakeLocationSummary() const {
-  ASSERT((left()->ResultCid() != kDoubleCid) &&
-         (right()->ResultCid() != kDoubleCid));
+  ASSERT((left()->Type()->ToCid() != kDoubleCid) &&
+         (right()->Type()->ToCid() != kDoubleCid));
   const intptr_t kNumInputs = 2;
   const intptr_t kNumTemps = 1;
   LocationSummary* summary =
     new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
   summary->set_in(0, Location::RequiresRegister());
   summary->set_in(1, Location::RequiresRegister());
   summary->set_temp(0, Location::RequiresRegister());
   return summary;
 }
 
@@ skipping 76 matching lines @@
   LocationSummary* summary =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
   summary->set_in(0, Location::RequiresRegister());
   if (CanDeoptimize()) summary->set_temp(0, Location::RequiresRegister());
   summary->set_out(Location::RequiresFpuRegister());
   return summary;
 }
 
 
 void UnboxDoubleInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  const intptr_t value_cid = value()->ResultCid();
+  const intptr_t value_cid = value()->Type()->ToCid();
   const Register value = locs()->in(0).reg();
   const XmmRegister result = locs()->out().fpu_reg();
 
   if (value_cid == kDoubleCid) {
     __ movsd(result, FieldAddress(value, Double::value_offset()));
   } else if (value_cid == kSmiCid) {
     __ SmiUntag(value);  // Untag input before conversion.
     __ cvtsi2sd(result, value);
     __ SmiTag(value);  // Restore input register.
   } else {
@@ skipping 381 matching lines @@
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;
   LocationSummary* summary =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
   summary->set_in(0, Location::RequiresRegister());
   return summary;
 }
 
 
 void CheckSmiInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  // TODO(srdjan): Check if we can remove this by reordering CSE and LICM.
-  if (value()->ResultCid() == kSmiCid) return;
   Register value = locs()->in(0).reg();
   Label* deopt = compiler->AddDeoptStub(deopt_id(),
                                         kDeoptCheckSmi);
   __ testq(value, Immediate(kSmiTagMask));
   __ j(NOT_ZERO, deopt);
 }
 
 
 LocationSummary* CheckArrayBoundInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 2;
@@ skipping 404 matching lines @@
                          PcDescriptors::kOther,
                          locs());
   __ Drop(2);  // Discard type arguments and receiver.
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64