On Thu, May 1, 2025 at 5:02 PM Andrew Pinski <quic_apin...@quicinc.com> wrote: > > While looking into bitwise optimizations, I noticed that > get_known_nonzero_bits_1 does `bm.value () & ~bm.mask ()` which > is ok except it creates a temporary wide_int. Instead if we > use wi::bit_and_not, we can avoid the temporary and on some > targets use the andn/bic instruction. > > Bootstrapped and tested on x86_64-linux-gnu.
OK. > gcc/ChangeLog: > > * tree-ssanames.cc (get_known_nonzero_bits_1): Use > wi::bit_and_not instead of `a & ~b`. > > Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com> > --- > gcc/tree-ssanames.cc | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/gcc/tree-ssanames.cc b/gcc/tree-ssanames.cc > index d7865f29f0b..de7b9b79f94 100644 > --- a/gcc/tree-ssanames.cc > +++ b/gcc/tree-ssanames.cc > @@ -576,7 +576,7 @@ get_known_nonzero_bits_1 (const_tree name) > if (tmp.undefined_p ()) > return wi::shwi (0, precision); > irange_bitmask bm = tmp.get_bitmask (); > - return bm.value () & ~bm.mask (); > + return wi::bit_and_not (bm.value (), bm.mask ()); > } > > /* Return a wide_int with known non-zero bits in SSA_NAME > -- > 2.43.0 >
