On Thu, Aug 24, 2023 at 11:39 PM Richard Biener via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> On Thu, Aug 24, 2023 at 9:16 PM Andrew Pinski via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
> >
> > In PR 106677, I noticed that on the trunk we were producing:
> > ```
> > _25 = SR.116_117 == 0;
> > _27 = (unsigned char) _25;
> > _32 = _27 | SR.116_117;
> > ```
> > From `SR.115_117 != 0 ? SR.115_117 : 1`
> > Rather than:
> > ```
> > _119 = MAX_EXPR <1, SR.115_117>;
> > ```
> > Or (rather)
> > ```
> > _119 = SR.115_117 | 1;
> > ```
> > Due to the order of the patterns.
>
> Hmm, that means the former when present in source isn't optimized?
That it is correct; they are not optimized at the gimple level down to
1. it is sometimes (but not on all targets) optimized at the RTL level
though.
>
> > OK? Bootstrapped and tested on x86_64-linux-gnu with no
> > regressions.
>
> OK, but please add a comment indicating the ordering requirement.
>
> Can you also add a testcase?
Yes and yes. Will send out a new patch in a few minutes with the added
comment and testcase.
Thanks,
Andrew
>
> Richard.
>
> > gcc/ChangeLog:
> >
> > * match.pd (`a ? one_zero : one_zero`): Move
> > below detection of minmax.
> > ---
> > gcc/match.pd | 38 ++++++++++++++++++++------------------
> > 1 file changed, 20 insertions(+), 18 deletions(-)
> >
> > diff --git a/gcc/match.pd b/gcc/match.pd
> > index 890f050cbad..c87a0795667 100644
> > --- a/gcc/match.pd
> > +++ b/gcc/match.pd
> > @@ -4950,24 +4950,6 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> > )
> > )
> >
> > -(simplify
> > - (cond @0 zero_one_valued_p@1 zero_one_valued_p@2)
> > - (switch
> > - /* bool0 ? bool1 : 0 -> bool0 & bool1 */
> > - (if (integer_zerop (@2))
> > - (bit_and (convert @0) @1))
> > - /* bool0 ? 0 : bool2 -> (bool0^1) & bool2 */
> > - (if (integer_zerop (@1))
> > - (bit_and (bit_xor (convert @0) { build_one_cst (type); } ) @2))
> > - /* bool0 ? 1 : bool2 -> bool0 | bool2 */
> > - (if (integer_onep (@1))
> > - (bit_ior (convert @0) @2))
> > - /* bool0 ? bool1 : 1 -> (bool0^1) | bool1 */
> > - (if (integer_onep (@2))
> > - (bit_ior (bit_xor (convert @0) @2) @1))
> > - )
> > -)
> > -
> > /* Optimize
> > # x_5 in range [cst1, cst2] where cst2 = cst1 + 1
> > x_5 ? cstN ? cst4 : cst3
> > @@ -5298,6 +5280,26 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> > && integer_nonzerop (fold_build2 (GE_EXPR, boolean_type_node,
> > @3, @1)))
> > (max @2 @4))))))
> >
> > +#if GIMPLE
> > +(simplify
> > + (cond @0 zero_one_valued_p@1 zero_one_valued_p@2)
> > + (switch
> > + /* bool0 ? bool1 : 0 -> bool0 & bool1 */
> > + (if (integer_zerop (@2))
> > + (bit_and (convert @0) @1))
> > + /* bool0 ? 0 : bool2 -> (bool0^1) & bool2 */
> > + (if (integer_zerop (@1))
> > + (bit_and (bit_xor (convert @0) { build_one_cst (type); } ) @2))
> > + /* bool0 ? 1 : bool2 -> bool0 | bool2 */
> > + (if (integer_onep (@1))
> > + (bit_ior (convert @0) @2))
> > + /* bool0 ? bool1 : 1 -> (bool0^1) | bool1 */
> > + (if (integer_onep (@2))
> > + (bit_ior (bit_xor (convert @0) @2) @1))
> > + )
> > +)
> > +#endif
> > +
> > /* X != C1 ? -X : C2 simplifies to -X when -C1 == C2. */
> > (simplify
> > (cond (ne @0 INTEGER_CST@1) (negate@3 @0) INTEGER_CST@2)
> > --
> > 2.31.1
> >
