On Thu, 3 Feb 2022, Jakub Jelinek wrote:
> Hi!
>
> The wide-int.h templates expect that when an int/long etc. operand is used
> it will be sign-extended based on the types precision.
> wi_fold_in_parts passes 3 such non-zero constants to wi::lt_p, wi::gt_p
> and wi::eq_p - 1, 3 and 4, which means it was doing weird things if either
> some of 1, 3 or 4 weren't representable in type, or if type was unsigned 3 bit
> type 4 should be written as -4.
> The following patch promotes the subtraction operands to widest_int and
> uses that as the type for ?h_range variables and compares them as such.
> We don't need the overflow handling because there is never an overflow.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux (on the former also
> with lto bootstrap), ok for trunk?
OK.
Thanks,
Richard.
> 2022-02-02 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/104334
> * range-op.cc (range_operator::wi_fold_in_parts): Change lh_range
> and rh_range type to widest_int and subtract in widest_int. Remove
> ov_rh, ov_lh and sign vars, always perform comparisons as signed
> and use >, < and == operators for it.
>
> * g++.dg/opt/pr104334.C: New test.
>
> --- gcc/range-op.cc.jj 2022-01-13 22:29:15.345831749 +0100
> +++ gcc/range-op.cc 2022-02-02 20:20:22.020000000 +0100
> @@ -144,22 +144,21 @@ range_operator::wi_fold_in_parts (irange
> const wide_int &rh_lb,
> const wide_int &rh_ub) const
> {
> - wi::overflow_type ov_rh, ov_lh;
> int_range_max tmp;
> - wide_int rh_range = wi::sub (rh_ub, rh_lb, TYPE_SIGN (type), &ov_rh);
> - wide_int lh_range = wi::sub (lh_ub, lh_lb, TYPE_SIGN (type), &ov_lh);
> - signop sign = TYPE_SIGN (type);;
> + widest_int rh_range = wi::sub (widest_int::from (rh_ub, TYPE_SIGN (type)),
> + widest_int::from (rh_lb, TYPE_SIGN (type)));
> + widest_int lh_range = wi::sub (widest_int::from (lh_ub, TYPE_SIGN (type)),
> + widest_int::from (lh_lb, TYPE_SIGN (type)));
> // If there are 2, 3, or 4 values in the RH range, do them separately.
> // Call wi_fold_in_parts to check the RH side.
> - if (wi::gt_p (rh_range, 0, sign) && wi::lt_p (rh_range, 4, sign)
> - && ov_rh == wi::OVF_NONE)
> + if (rh_range > 0 && rh_range < 4)
> {
> wi_fold_in_parts (r, type, lh_lb, lh_ub, rh_lb, rh_lb);
> - if (wi::gt_p (rh_range, 1, sign))
> + if (rh_range > 1)
> {
> wi_fold_in_parts (tmp, type, lh_lb, lh_ub, rh_lb + 1, rh_lb + 1);
> r.union_ (tmp);
> - if (wi::eq_p (rh_range, 3))
> + if (rh_range == 3)
> {
> wi_fold_in_parts (tmp, type, lh_lb, lh_ub, rh_lb + 2, rh_lb + 2);
> r.union_ (tmp);
> @@ -170,15 +169,14 @@ range_operator::wi_fold_in_parts (irange
> }
> // Otherise check for 2, 3, or 4 values in the LH range and split them up.
> // The RH side has been checked, so no recursion needed.
> - else if (wi::gt_p (lh_range, 0, sign) && wi::lt_p (lh_range, 4, sign)
> - && ov_lh == wi::OVF_NONE)
> + else if (lh_range > 0 && lh_range < 4)
> {
> wi_fold (r, type, lh_lb, lh_lb, rh_lb, rh_ub);
> - if (wi::gt_p (lh_range, 1, sign))
> + if (lh_range > 1)
> {
> wi_fold (tmp, type, lh_lb + 1, lh_lb + 1, rh_lb, rh_ub);
> r.union_ (tmp);
> - if (wi::eq_p (lh_range, 3))
> + if (lh_range == 3)
> {
> wi_fold (tmp, type, lh_lb + 2, lh_lb + 2, rh_lb, rh_ub);
> r.union_ (tmp);
> --- gcc/testsuite/g++.dg/opt/pr104334.C.jj 2022-02-02 14:35:51.184657968
> +0100
> +++ gcc/testsuite/g++.dg/opt/pr104334.C 2022-02-02 14:37:14.888478594
> +0100
> @@ -0,0 +1,40 @@
> +// PR tree-optimization/104334
> +// { dg-do run { target c++11 } }
> +// { dg-options "-O2 --param logical-op-non-short-circuit=0" }
> +
> +enum class A { A0, A1, A2, A3 };
> +int x;
> +
> +__attribute__((noipa)) void
> +baz ()
> +{
> + x = 1;
> +}
> +
> +struct B {
> + unsigned b : 2;
> +
> + A
> + foo () const
> + {
> + return static_cast<A> (b);
> + }
> +
> + __attribute__((noinline)) void
> + bar ()
> + {
> + if (foo () == A::A2 || foo () == A::A3)
> + baz ();
> + }
> +};
> +
> +int
> +main ()
> +{
> + B c;
> + c.b = 2;
> + c.bar ();
> + if (x != 1)
> + __builtin_abort ();
> + return 0;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Ivo Totev; HRB 36809 (AG Nuernberg)
