[LLVMdev] test all ones/zeros in vector

[Roland Leißa]

Hi all,

is there a portable and effective way of emitting code which checks whether all vector elements are true or false?

Currently, I'm doing this:

  %sext = sext <4 x i1> %my_cmp to <4 x i8>
  %bcast = bitcast <4 x i8> %sext to i32
  %all_zeros = icmp ne i32 %bcast, 0
  br i1 %all_zeros, label %A, label %B


The emitted code works, but it's not great. I'd like to make use of movmask or ptest in the case of SSE.

Of course, I could emit some intrinsic functions but I always consider these kind of things a hack; I'd rather like to emit some code which the back-end likes. So is there some llvm code sequence which does the trick?

-- 
Roland