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

src/compiler/x87/code-generator-x87.cc

Index: src/compiler/x87/code-generator-x87.cc
diff --git a/src/compiler/x87/code-generator-x87.cc b/src/compiler/x87/code-generator-x87.cc
index 03d79bf328fdc153249fb9497337bc94ccca94cb..89ecff0a709dc4dab18f760ae834abe79cb4aa85 100644
--- a/src/compiler/x87/code-generator-x87.cc
+++ b/src/compiler/x87/code-generator-x87.cc
@@ -544,6 +544,9 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kX87Lzcnt:
       __ Lzcnt(i.OutputRegister(), i.InputOperand(0));
       break;
+    case kX87Popcnt:
+      __ Popcnt(i.OutputRegister(), i.InputOperand(0));
+      break;
     case kX87LoadFloat64Constant: {
       InstructionOperand* source = instr->InputAt(0);
       InstructionOperand* destination = instr->Output();