Fixed and improved code for integral division. Fixed and extended tests.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 666b688c92abf61b066343076bd0466b39be47e7..e342acbcb83cb5538f08d11c8e48ba319a9bbaa2 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1240,10 +1240,10 @@ LInstruction* LChunkBuilder::DoDiv(HDiv* instr) {
     ASSERT(instr->right()->representation().Equals(instr->representation()));
     if (instr->RightIsPowerOf2()) {
       ASSERT(!instr->CheckFlag(HValue::kCanBeDivByZero));
-      LOperand* value = UseRegisterAtStart(instr->left());
+      LOperand* value = UseRegister(instr->left());
       LDivI* div =
           new(zone()) LDivI(value, UseOrConstant(instr->right()), NULL);
-      return AssignEnvironment(DefineSameAsFirst(div));
+      return AssignEnvironment(DefineAsRegister(div));
     }
     // The temporary operand is necessary to ensure that right is not allocated
     // into rdx.