Improve integer division on IA32 and X64

src/x64/lithium-x64.cc

 // Copyright 2012 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 1169 matching lines @@
   LOperand* input = UseRegisterAtStart(instr->value());
   LBitNotI* result = new(zone()) LBitNotI(input);
   return DefineSameAsFirst(result);
 }
 
 
 LInstruction* LChunkBuilder::DoDiv(HDiv* instr) {
   if (instr->representation().IsDouble()) {
     return DoArithmeticD(Token::DIV, instr);
   } else if (instr->representation().IsInteger32()) {
+    if (instr->HasPowerOf2Divisor()) {
+      ASSERT(!instr->CheckFlag(HValue::kCanBeDivByZero));
+      LOperand* value = UseRegisterAtStart(instr->left());
+      LDivI* div =
+          new(zone()) LDivI(value, UseOrConstant(instr->right()), NULL);
+      return AssignEnvironment(DefineSameAsFirst(div));
+    }
     // The temporary operand is necessary to ensure that right is not allocated
     // into rdx.
     LOperand* temp = FixedTemp(rdx);
     LOperand* dividend = UseFixed(instr->left(), rax);
     LOperand* divisor = UseRegister(instr->right());
     LDivI* result = new(zone()) LDivI(dividend, divisor, temp);
     return AssignEnvironment(DefineFixed(result, rax));
   } else {
     ASSERT(instr->representation().IsTagged());
     return DoArithmeticT(Token::DIV, instr);
@@ skipping 1120 matching lines @@
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseTempRegister(instr->index());
   return DefineSameAsFirst(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64