In strict comarison use constants instead of registers if possible.

runtime/vm/intermediate_language.cc

 // Copyright (c) 2012, 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/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 1542 matching lines @@
 }
 
 
 void StoreContextInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   // Nothing to do.  Context register were loaded by register allocator.
   ASSERT(locs()->in(0).reg() == CTX);
 }
 
 
 LocationSummary* StrictCompareInstr::MakeLocationSummary() const {
-  return LocationSummary::Make(2,
-                               Location::SameAsFirstInput(),
-                               LocationSummary::kNoCall);
+  const intptr_t kNumInputs = 2;
+  const intptr_t kNumTemps = 0;
+  LocationSummary* locs =
+      new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
+  locs->set_in(0, Location::RegisterOrConstant(left()));
+  locs->set_in(1, Location::RegisterOrConstant(right()));
+  locs->set_out(Location::RequiresRegister());
+  return locs;
 }
 
 
 void StrictCompareInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  Register left = locs()->in(0).reg();
-  Register right = locs()->in(1).reg();
-
   ASSERT(kind() == Token::kEQ_STRICT || kind() == Token::kNE_STRICT);
   Condition true_condition = (kind() == Token::kEQ_STRICT) ? EQUAL : NOT_EQUAL;
-  __ CompareRegisters(left, right);
+  Location left = locs()->in(0);
+  Location right = locs()->in(1);
+  if (left.IsConstant() && right.IsConstant()) {
+    // TODO(vegorov): should be eliminated earlier by constant propagation.
+    const bool result = left.constant().raw() == right.constant().raw();
+    __ LoadObject(locs()->out().reg(), result ? compiler->bool_true() :
+                                                compiler->bool_false());
+    return;
+  }
+  if (left.IsConstant()) {
+    __ CompareObject(right.reg(), left.constant());
+  } else if (right.IsConstant()) {
+    __ CompareObject(left.reg(), right.constant());
+  } else {
+    __ CompareRegisters(left.reg(), right.reg());
+  }
 
   Register result = locs()->out().reg();
   Label load_true, done;
   __ j(true_condition, &load_true, Assembler::kNearJump);
   __ LoadObject(result, compiler->bool_false());
   __ jmp(&done, Assembler::kNearJump);
   __ Bind(&load_true);
   __ LoadObject(result, compiler->bool_true());
   __ Bind(&done);
 }
 
 
 void StrictCompareInstr::EmitBranchCode(FlowGraphCompiler* compiler,
-                                       BranchInstr* branch) {
-  Register left = locs()->in(0).reg();
-  Register right = locs()->in(1).reg();
+                                        BranchInstr* branch) {
   ASSERT(kind() == Token::kEQ_STRICT || kind() == Token::kNE_STRICT);
   Condition true_condition = (kind() == Token::kEQ_STRICT) ? EQUAL : NOT_EQUAL;
-  __ CompareRegisters(left, right);
+  Location left = locs()->in(0);
+  Location right = locs()->in(1);
+  if (left.IsConstant() && right.IsConstant()) {
+    // TODO(vegorov): should be eliminated earlier by constant propagation.
+    const bool result = left.constant().raw() == right.constant().raw();
+    branch->EmitBranchOnValue(compiler, result);
+    return;
+  }
+  if (left.IsConstant()) {
+    __ CompareObject(right.reg(), left.constant());
+  } else if (right.IsConstant()) {
+    __ CompareObject(left.reg(), right.constant());
+  } else {
+    __ CompareRegisters(left.reg(), right.reg());
+  }
+
   branch->EmitBranchOnCondition(compiler, true_condition);
 }
 
 
 void ClosureCallInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   // The arguments to the stub include the closure.  The arguments
   // descriptor describes the closure's arguments (and so does not include
   // the closure).
   Register temp_reg = locs()->temp(0).reg();
   int argument_count = ArgumentCount();
@@ skipping 395 matching lines @@
     new_max = new_max.Clamp();
   }
 
   return Range::Update(&range_, new_min, new_max);
 }
 
 
 #undef __
 
 }  // namespace dart