Revert of [turbofan] Implemented the TruncateFloat32ToInt64 TurboFan operator.

src/compiler/x64/code-generator-x64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/code-generator.h"
 
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/osr.h"
@@ skipping 1025 matching lines @@
       break;
     case kSSEFloat64ToUint32: {
       if (instr->InputAt(0)->IsDoubleRegister()) {
         __ Cvttsd2siq(i.OutputRegister(), i.InputDoubleRegister(0));
       } else {
         __ Cvttsd2siq(i.OutputRegister(), i.InputOperand(0));
       }
       __ AssertZeroExtended(i.OutputRegister());
       break;
     }
-    case kSSEFloat32ToInt64:
-      if (instr->InputAt(0)->IsDoubleRegister()) {
-        __ Cvttss2siq(i.OutputRegister(), i.InputDoubleRegister(0));
-      } else {
-        __ Cvttss2siq(i.OutputRegister(), i.InputOperand(0));
-      }
-      break;
     case kSSEFloat64ToInt64:
       if (instr->InputAt(0)->IsDoubleRegister()) {
         __ Cvttsd2siq(i.OutputRegister(), i.InputDoubleRegister(0));
       } else {
         __ Cvttsd2siq(i.OutputRegister(), i.InputOperand(0));
       }
       break;
     case kSSEFloat64ToUint64: {
       // There does not exist a Float64ToUint64 instruction, so we have to use
       // the Float64ToInt64 instruction.
@@ skipping 948 matching lines @@
     int padding_size = last_lazy_deopt_pc_ + space_needed - current_pc;
     __ Nop(padding_size);
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8