+// Default arguments for various fp stack instructions.
+def : InstAlias<"fucom", (UCOM_Fr ST1)>;
+def : InstAlias<"fucomp", (UCOM_FPr ST1)>;
+def : InstAlias<"fcomi", (COM_FIr ST1)>;
+def : InstAlias<"fcomi $reg", (COM_FIr RST:$reg)>;
+def : InstAlias<"fcomip", (COM_FIPr ST1)>;
+def : InstAlias<"fcomip $reg", (COM_FIPr RST:$reg)>;
+def : InstAlias<"fucomi", (UCOM_FIr ST1)>;
+def : InstAlias<"fucomi $reg", (UCOM_FIr RST:$reg)>;
+def : InstAlias<"fucomip", (UCOM_FIPr ST1)>;
+def : InstAlias<"fucomip $reg", (UCOM_FIPr RST:$reg)>;
+
+
+// We accepts "fnstsw %eax" even though it only writes %ax.
+def : InstAlias<"fnstsw %eax", (FNSTSW8r)>;
+def : InstAlias<"fnstsw %al" , (FNSTSW8r)>;
+def : InstAlias<"fnstsw" , (FNSTSW8r)>;
+