X87: Added Popcnt as an optional operator and implement it on x64 and ia32.

src/x87/macro-assembler-x87.cc

Index: src/x87/macro-assembler-x87.cc
diff --git a/src/x87/macro-assembler-x87.cc b/src/x87/macro-assembler-x87.cc
index bb877fe69775b5c904dcd900769db5e994c95a61..ddea111f188d898dfd16f3d1c9599db1a2943784 100644
--- a/src/x87/macro-assembler-x87.cc
+++ b/src/x87/macro-assembler-x87.cc
@@ -2327,6 +2327,17 @@ void MacroAssembler::Tzcnt(Register dst, const Operand& src) {
 }
 
 
+void MacroAssembler::Popcnt(Register dst, const Operand& src) {
+  // TODO(intel): Add support for POPCNT (with POPCNT)
+  // if (CpuFeatures::IsSupported(POPCNT)) {
+  //   CpuFeatureScope scope(this, POPCNT);
+  //   popcnt(dst, src);
+  //   return;
+  // }
+  UNREACHABLE();
+}
+
+
 void MacroAssembler::SetCounter(StatsCounter* counter, int value) {
   if (FLAG_native_code_counters && counter->Enabled()) {
     mov(Operand::StaticVariable(ExternalReference(counter)), Immediate(value));