Remove bogus check for TOP register in deoptimizer.

src/ia32/deoptimizer-ia32.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 1196 matching lines @@
     CpuFeatures::Scope scope(SSE2);
     // Fill in the double input registers.
     for (int i = 0; i < XMMRegister::kNumAllocatableRegisters; ++i) {
       int dst_offset = i * kDoubleSize + double_regs_offset;
       int src_offset = i * kDoubleSize;
       __ movdbl(xmm0, Operand(esp, src_offset));
       __ movdbl(Operand(ebx, dst_offset), xmm0);
     }
   }
 
-  // Check that the TOP register is zero and clear all exceptions.
-  const int kTopMask = 0x3800;
-  __ push(eax);
-  __ fwait();
-  __ fnstsw_ax();
-  __ test(eax, Immediate(kTopMask));
-  __ Check(zero, "FPU TOP is not zero in deoptimizer.");
+  // Clear FPU all exceptions.
+  // TODO(ulan): Find out why the TOP register is not zero here in some cases,
+  // and check that the generated code never deoptimizes with unbalanced stack.
   __ fnclex();
-  __ pop(eax);
 
   // Remove the bailout id and the double registers from the stack.
   if (type() == EAGER) {
     __ add(esp, Immediate(kDoubleRegsSize + kPointerSize));
   } else {
     __ add(esp, Immediate(kDoubleRegsSize + 2 * kPointerSize));
   }
 
   // Compute a pointer to the unwinding limit in register ecx; that is
   // the first stack slot not part of the input frame.
@@ skipping 116 matching lines @@
   }
   __ bind(&done);
 }
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32