X87: CTZ instruction implemented as optional operator.

src/x87/assembler-x87.h

Index: src/x87/assembler-x87.h
diff --git a/src/x87/assembler-x87.h b/src/x87/assembler-x87.h
index a5127d30259d4771c9b63e9271ade03c4583cfd2..aa5195c9516377e3914da8943098aa71ac872b2c 100644
--- a/src/x87/assembler-x87.h
+++ b/src/x87/assembler-x87.h
@@ -771,6 +771,8 @@ class Assembler : public AssemblerBase {
   void bts(const Operand& dst, Register src);
   void bsr(Register dst, Register src) { bsr(dst, Operand(src)); }
   void bsr(Register dst, const Operand& src);
+  void bsf(Register dst, Register src) { bsf(dst, Operand(src)); }
+  void bsf(Register dst, const Operand& src);
 
   // Miscellaneous
   void hlt();