Hi Dominik, Thanks for the example. ROSBG, what a weird instruction.
On Thu, Jan 05, 2017 at 05:46:51PM +0100, Dominik Vogt wrote: > --- a/gcc/combine.c > +++ b/gcc/combine.c > @@ -11372,6 +11372,16 @@ change_zero_ext_src (subrtx_ptr_iterator *piter) > else if (GET_CODE (x) == ZERO_EXTEND > && SCALAR_INT_MODE_P (mode) > && REG_P (XEXP (x, 0)) > + && !HARD_REGISTER_P (XEXP (x, 0)) > + && GET_MODE_PRECISION (GET_MODE (XEXP (x, 0))) > + < GET_MODE_PRECISION (mode)) > + { > + /* (zero_extract (reg)) -> (and (subreg (reg) 0) (const_int)) */ s/zero_extract/zero_extend/ > * combine.c (change_zero_ext_src): Handle zero_extend without subreg. "Handle zero_extend of a pseudo."? Okay for trunk with that. Thanks for the patch, Segher