The following fails on x86_64 because of the output constraint '0'.
My question is, is this legal. LLVM complains about the size difference
(32 vs 64), but it is the same register (ax).
Works on x86.
%42 = call i64 asm sideeffect "syscall\0A\09",
"={ax},0,{di},~{dirflag},~{fpsr},~{flags}"(i64 231, i64 %41) nounwind
; <i64> [#uses=2]
-Rich