On Fri, Jan 15, 2021 at 08:50:20PM +0100, Richard Biener wrote:
> On January 15, 2021 7:38:35 PM GMT+01:00, Jakub Jelinek <ja...@redhat.com>
> wrote:
> >Hi!
> >
> >The following patch generalizes the PR64309 simplifications, so that
> >instead
> >of working only with constants 1 and 1 it works with any two power of
> >two
> >constants, and works also for right shift (in that case it rules out
> >the
> >first one being negative, as it is arithmetic shift then).
> >
> >Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> Ok.
Thanks.
BTW, I've tried to also fix what the PR wanted primarily by adding
/* Simplify (CST << x) & 1 to 0 if CST is even or to x == 0 if it is odd. /
(simplify
(bit_and (lshift INTEGER_CST@1 @0) integer_onep)
(if ((wi::to_wide (@1) & 1) != 0)
(eq @0 { build_zero_cst (TREE_TYPE (@0)); })
({ build_zero_cst (type); })))
simplifier before this one, but genmatch.c doesn't seem to put it into the
resulting files. Is there a way to figure out what is going on?
I remember you said one can't have multiple too similar rules,
but the closest one I can find is
(for shift (lshift rshift)
(simplify
(bit_and (convert?:s@4 (shift:s@5 (convert1?@3 @0) INTEGER_CST@1))
INTEGER_CST@2)
Is it that one that makes the above not work and shall I then
stick it into the same simplifier?
What I want has the @1 in this one actually not an INTEGER_CST, while @3
shall be INTEGER_CST...
Jakub
