[x64] Introduce FMA3 instructions on scalar data elements.

src/base/cpu.cc

Index: src/base/cpu.cc
diff --git a/src/base/cpu.cc b/src/base/cpu.cc
index 5bc8b13a97ba2fb9ca2094e32b43d288cf3b0157..db733e4dbdf94cbc34c503fff6ce9660f7bb076a 100644
--- a/src/base/cpu.cc
+++ b/src/base/cpu.cc
@@ -291,32 +291,35 @@ static bool HasListItem(const char* list, const char* item) {
 
 #endif  // V8_HOST_ARCH_IA32 || V8_HOST_ARCH_X64
 
-CPU::CPU() : stepping_(0),
-             model_(0),
-             ext_model_(0),
-             family_(0),
-             ext_family_(0),
-             type_(0),
-             implementer_(0),
-             architecture_(0),
-             part_(0),
-             has_fpu_(false),
-             has_cmov_(false),
-             has_sahf_(false),
-             has_mmx_(false),
-             has_sse_(false),
-             has_sse2_(false),
-             has_sse3_(false),
-             has_ssse3_(false),
-             has_sse41_(false),
-             has_sse42_(false),
-             has_idiva_(false),
-             has_neon_(false),
-             has_thumb2_(false),
-             has_vfp_(false),
-             has_vfp3_(false),
-             has_vfp3_d32_(false),
-             is_fp64_mode_(false) {
+CPU::CPU()
+    : stepping_(0),
+      model_(0),
+      ext_model_(0),
+      family_(0),
+      ext_family_(0),
+      type_(0),
+      implementer_(0),
+      architecture_(0),
+      part_(0),
+      has_fpu_(false),
+      has_cmov_(false),
+      has_sahf_(false),
+      has_mmx_(false),
+      has_sse_(false),
+      has_sse2_(false),
+      has_sse3_(false),
+      has_ssse3_(false),
+      has_sse41_(false),
+      has_sse42_(false),
+      has_avx_(false),
+      has_fma3_(false),
+      has_idiva_(false),
+      has_neon_(false),
+      has_thumb2_(false),
+      has_vfp_(false),
+      has_vfp3_(false),
+      has_vfp3_d32_(false),
+      is_fp64_mode_(false) {
   memcpy(vendor_, "Unknown", 8);
 #if V8_OS_NACL
 // Portable host shouldn't do feature detection.
@@ -356,6 +359,8 @@ CPU::CPU() : stepping_(0),
     has_ssse3_ = (cpu_info[2] & 0x00000200) != 0;
     has_sse41_ = (cpu_info[2] & 0x00080000) != 0;
     has_sse42_ = (cpu_info[2] & 0x00100000) != 0;
+    has_avx_ = (cpu_info[2] & 0x18000000) != 0;
+    if (has_avx_) has_fma3_ = (cpu_info[2] & 0x00001000) != 0;
   }
 
 #if V8_HOST_ARCH_IA32