Revert r10908 due to flakiness and crashes.

src/mips/lithium-mips.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 1151 matching lines @@
 LInstruction* LChunkBuilder::DoInvokeFunction(HInvokeFunction* instr) {
   LOperand* function = UseFixed(instr->function(), a1);
   argument_count_ -= instr->argument_count();
   LInvokeFunction* result = new(zone()) LInvokeFunction(function);
   return MarkAsCall(DefineFixed(result, v0), instr, CANNOT_DEOPTIMIZE_EAGERLY);
 }
 
 
 LInstruction* LChunkBuilder::DoUnaryMathOperation(HUnaryMathOperation* instr) {
   BuiltinFunctionId op = instr->op();
-  if (op == kMathLog || op == kMathSin || op == kMathCos || op == kMathTan) {
+  if (op == kMathLog || op == kMathSin || op == kMathCos) {
     LOperand* input = UseFixedDouble(instr->value(), f4);
     LUnaryMathOperation* result = new(zone()) LUnaryMathOperation(input, NULL);
     return MarkAsCall(DefineFixedDouble(result, f4), instr);
   } else if (op == kMathPowHalf) {
     // Input cannot be the same as the result.
     // See lithium-codegen-mips.cc::DoMathPowHalf.
     LOperand* input = UseFixedDouble(instr->value(), f8);
     LOperand* temp = FixedTemp(f6);
     LUnaryMathOperation* result = new(zone()) LUnaryMathOperation(input, temp);
     return DefineFixedDouble(result, f4);
@@ skipping 1123 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseRegister(instr->index());
   return DefineAsRegister(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal