Fix Smi-based MathMinMax on x64, and reenable smi mode.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1681 matching lines @@
     }
   }
 }
 
 
 void LCodeGen::DoMathMinMax(LMathMinMax* instr) {
   LOperand* left = instr->left();
   LOperand* right = instr->right();
   ASSERT(left->Equals(instr->result()));
   HMathMinMax::Operation operation = instr->hydrogen()->operation();
-  if (instr->hydrogen()->representation().IsInteger32()) {
+  if (instr->hydrogen()->representation().IsSmiOrInteger32()) {
     Label return_left;
     Condition condition = (operation == HMathMinMax::kMathMin)
         ? less_equal
         : greater_equal;
     Register left_reg = ToRegister(left);
     if (right->IsConstantOperand()) {
       Immediate right_imm =
           Immediate(ToInteger32(LConstantOperand::cast(right)));
+      ASSERT(!instr->hydrogen_value()->representation().IsSmi());
       __ cmpl(left_reg, right_imm);
       __ j(condition, &return_left, Label::kNear);
       __ movq(left_reg, right_imm);
     } else if (right->IsRegister()) {
       Register right_reg = ToRegister(right);
-      __ cmpl(left_reg, right_reg);
+      if (instr->hydrogen_value()->representation().IsSmi()) {
+        __ cmpq(left_reg, right_reg);
+      } else {
+        __ cmpl(left_reg, right_reg);
+      }
       __ j(condition, &return_left, Label::kNear);
       __ movq(left_reg, right_reg);
     } else {
       Operand right_op = ToOperand(right);
-      __ cmpl(left_reg, right_op);
+      if (instr->hydrogen_value()->representation().IsSmi()) {
+        __ cmpq(left_reg, right_op);
+      } else {
+        __ cmpl(left_reg, right_op);
+      }
       __ j(condition, &return_left, Label::kNear);
       __ movq(left_reg, right_op);
     }
     __ bind(&return_left);
   } else {
     ASSERT(instr->hydrogen()->representation().IsDouble());
     Label check_nan_left, check_zero, return_left, return_right;
     Condition condition = (operation == HMathMinMax::kMathMin) ? below : above;
     XMMRegister left_reg = ToDoubleRegister(left);
     XMMRegister right_reg = ToDoubleRegister(right);
@@ skipping 3814 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64