+// 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)>;
+
+// lcall and ljmp aliases. This seems to be an odd mapping in 64-bit mode, but
+// this is compatible with what GAS does.
+def : InstAlias<"lcall $seg, $off", (FARCALL32i i32imm:$off, i16imm:$seg)>;
+def : InstAlias<"ljmp $seg, $off", (FARJMP32i i32imm:$off, i16imm:$seg)>;
+def : InstAlias<"lcall *$dst", (FARCALL32m opaque48mem:$dst)>;
+def : InstAlias<"ljmp *$dst", (FARJMP32m opaque48mem:$dst)>;
+
+// "imul <imm>, B" is an alias for "imul <imm>, B, B".
+def : InstAlias<"imulw $imm, $r", (IMUL16rri GR16:$r, GR16:$r, i16imm:$imm)>;
+def : InstAlias<"imulw $imm, $r", (IMUL16rri8 GR16:$r, GR16:$r, i16i8imm:$imm)>;
+def : InstAlias<"imull $imm, $r", (IMUL32rri GR32:$r, GR32:$r, i32imm:$imm)>;
+def : InstAlias<"imull $imm, $r", (IMUL32rri8 GR32:$r, GR32:$r, i32i8imm:$imm)>;
+def : InstAlias<"imulq $imm, $r",(IMUL64rri32 GR64:$r, GR64:$r,i64i32imm:$imm)>;
+def : InstAlias<"imulq $imm, $r", (IMUL64rri8 GR64:$r, GR64:$r, i64i8imm:$imm)>;
+
+// inb %dx -> inb %al, %dx
+def : InstAlias<"inb %dx", (IN8rr)>;
+def : InstAlias<"inw %dx", (IN16rr)>;
+def : InstAlias<"inl %dx", (IN32rr)>;
+def : InstAlias<"inb $port", (IN8ri i8imm:$port)>;
+def : InstAlias<"inw $port", (IN16ri i8imm:$port)>;
+def : InstAlias<"inl $port", (IN32ri i8imm:$port)>;
+
+
+// jmp and call aliases for lcall and ljmp. jmp $42,$5 -> ljmp
+def : InstAlias<"call $seg, $off", (FARCALL32i i32imm:$off, i16imm:$seg)>;
+def : InstAlias<"jmp $seg, $off", (FARJMP32i i32imm:$off, i16imm:$seg)>;
+def : InstAlias<"callw $seg, $off", (FARCALL16i i16imm:$off, i16imm:$seg)>;
+def : InstAlias<"jmpw $seg, $off", (FARJMP16i i16imm:$off, i16imm:$seg)>;
+def : InstAlias<"calll $seg, $off", (FARCALL32i i32imm:$off, i16imm:$seg)>;
+def : InstAlias<"jmpl $seg, $off", (FARJMP32i i32imm:$off, i16imm:$seg)>;
+
+
+// Match 'movq <largeimm>, <reg>' as an alias for movabsq.
+def : InstAlias<"movq $imm, $reg", (MOV64ri GR64:$reg, i64imm:$imm)>;
+
+// movsd with no operands (as opposed to the SSE scalar move of a double) is an
+// alias for movsl. (as in rep; movsd)
+def : InstAlias<"movsd", (MOVSD)>;
+