On Wed, Apr 15, 2020 at 10:18:16AM +0100, Richard Sandiford wrote:
> luoxhu--- via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> > - count = simplify_gen_binary (PLUS, mode, count, const1_rtx);
> > + {
> > + /* Fold (add -1; zero_ext; add +1) operations to zero_ext based on
> > addop0
> > + is never zero, as gimple pass loop ch will do optimization to simplify
> > + the loop to NO loop for loop condition is false. */
>
> IMO the code needs to prove this, rather than just assume that previous
> passes have made it so.
Well, it should gcc_assert it, probably.
It is the left-hand side of a+b... it cannot be 0, because niter always
is simplified!
Segher
