Require CMOV support for the ia32 port.

src/x64/assembler-x64.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // 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.
 //
@@ skipping 440 matching lines @@
   // Detect features of the target CPU. Set safe defaults if the serializer
   // is enabled (snapshots must be portable).
   static void Probe(bool serializer_enabled);
 
   // Check whether a feature is supported by the target CPU.
   static bool IsSupported(CpuFeature f) {
     if (Check(f, cross_compile_)) return true;
     ASSERT(initialized_);
     if (f == SSE3 && !FLAG_enable_sse3) return false;
     if (f == SSE4_1 && !FLAG_enable_sse4_1) return false;
-    if (f == CMOV && !FLAG_enable_cmov) return false;
     if (f == SAHF && !FLAG_enable_sahf) return false;
     return Check(f, supported_);
   }
 
   static bool IsSafeForSnapshot(Isolate* isolate, CpuFeature f) {
     return Check(f, cross_compile_) ||
            (IsSupported(f) &&
             !(Serializer::enabled(isolate) &&
               Check(f, found_by_runtime_probing_only_)));
   }
@@ skipping 12 matching lines @@
 
  private:
   static bool Check(CpuFeature f, uint64_t set) {
     return (set & flag2set(f)) != 0;
   }
 
   static uint64_t flag2set(CpuFeature f) {
     return static_cast<uint64_t>(1) << f;
   }
 
-  // Safe defaults include CMOV for X64. It is always available, if
-  // anyone checks, but they shouldn't need to check.
-  // The required user mode extensions in X64 are (from AMD64 ABI Table A.1):
-  //   fpu, tsc, cx8, cmov, mmx, sse, sse2, fxsr, syscall
-  static const uint64_t kDefaultCpuFeatures = (1 << CMOV);
-
 #ifdef DEBUG
   static bool initialized_;
 #endif
   static uint64_t supported_;
   static uint64_t found_by_runtime_probing_only_;
 
   static uint64_t cross_compile_;
 
   friend class ExternalReference;
   friend class PlatformFeatureScope;
@@ skipping 1140 matching lines @@
  private:
   Assembler* assembler_;
 #ifdef DEBUG
   int space_before_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_ASSEMBLER_X64_H_