Use range information for optimizing integer boxing and fix bug in range analysis.

runtime/vm/intermediate_language_ia32.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_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 5645 matching lines @@
     // Sign extend into result_hi.
     __ cdq();
     __ Bind(&done);
   }
 }
 
 
 LocationSummary* BoxIntegerInstr::MakeLocationSummary(Isolate* isolate,
                                                       bool opt) const {
   const intptr_t kNumInputs = 1;
-  const intptr_t kNumTemps = 1;
+  const intptr_t kNumTemps = is_smi() ? 0 : 1;
   LocationSummary* summary = new(isolate) LocationSummary(
       isolate, kNumInputs,
                           kNumTemps,
-                          LocationSummary::kCallOnSlowPath);
+                          is_smi()
+                              ? LocationSummary::kNoCall
+                              : LocationSummary::kCallOnSlowPath);
   summary->set_in(0, Location::Pair(Location::RequiresRegister(),
                                     Location::RequiresRegister()));
-  summary->set_temp(0, Location::RequiresRegister());
+  if (!is_smi()) {
+    summary->set_temp(0, Location::RequiresRegister());
+  }
   summary->set_out(0, Location::RequiresRegister());
   return summary;
 }
 
 
 class BoxIntegerSlowPath : public SlowPathCode {
  public:
   explicit BoxIntegerSlowPath(BoxIntegerInstr* instruction)
       : instruction_(instruction) { }
 
@@ skipping 19 matching lines @@
 
     __ jmp(exit_label());
   }
 
  private:
   BoxIntegerInstr* instruction_;
 };
 
 
 void BoxIntegerInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
+  if (is_smi()) {
+    PairLocation* value_pair = locs()->in(0).AsPairLocation();
+    Register value_lo = value_pair->At(0).reg();
+    Register out_reg = locs()->out(0).reg();
+    __ movl(out_reg, value_lo);
+    __ SmiTag(out_reg);
+    return;
+  }
+
   BoxIntegerSlowPath* slow_path = new BoxIntegerSlowPath(this);
   compiler->AddSlowPathCode(slow_path);
   PairLocation* value_pair = locs()->in(0).AsPairLocation();
   Register value_lo = value_pair->At(0).reg();
   Register value_hi = value_pair->At(1).reg();
   Register out_reg = locs()->out(0).reg();
 
   // Copy value_hi into out_reg as a temporary.
   // We modify value_lo but restore it before using it.
   __ movl(out_reg, value_hi);
@@ skipping 584 matching lines @@
   __ movl(EDX, Immediate(kInvalidObjectPointer));
   __ movl(EDX, Immediate(kInvalidObjectPointer));
 #endif
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_IA32