Require CMOV support for the ia32 port.

src/x64/assembler-x64.h

Index: src/x64/assembler-x64.h
diff --git a/src/x64/assembler-x64.h b/src/x64/assembler-x64.h
index 552c4f89802a4a1a1f2a488cb75966940cb267b0..9d421ef6c11c10d4f76c386816615b938f44d7f2 100644
--- a/src/x64/assembler-x64.h
+++ b/src/x64/assembler-x64.h
@@ -458,7 +458,6 @@ class CpuFeatures : public AllStatic {
     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_);
   }
@@ -491,12 +490,6 @@ class CpuFeatures : public AllStatic {
     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