"Paulo J. Matos" <pocma...@gmail.com> writes: > In a rule like > (set (match_operand 0 ...) > (match_operand 1 ...)) > > I sometimes have operand0 equal to operand1, as in > rtx_equal_p(operand[0], operand[1]) == 1. > This generates a move between the same location (same as a nop). > > Is there a reason for getting this and is it up to me to handle it or > this is just the result of some problem with my md file? I am in > gcc4.4.4.
Moves between the same register are normally eliminated by a loop at the end of reload(). Does your processor support memory-to-memory moves? I don't think anything will explicitly eliminate those, though I'm also not sure why they would be created in the first place. I'm surprised that it happens, but I don't know what would cause it. In particular I don't know that it is a problem in your MD file. You'll have to find out where they are coming from. Ian
