On Thu, 3 Aug 2017, Jakub Jelinek wrote:
> Hi!
>
> For the PR81588 testcase, on targets with branch cost 1, we end up with:
> b.0_1 = b;
> _2 = (long long int) b.0_1;
> a.1_3 = a;
> _4 = _2 > a.1_3;
> _5 = (int) _4;
> if (a.1_3 < 0)
> goto <bb 4>; [36.00%] [count: INV]
> else
> goto <bb 3>; [64.00%] [count: INV]
>
> <bb 3> [64.00%] [count: INV]:
> if (_4 != 1)
> goto <bb 4>; [46.88%] [count: INV]
> else
> goto <bb 5>; [53.13%] [count: INV]
>
> <bb 4> [66.00%] [count: INV]:
> c = 0;
>
> <bb 5> [100.00%] [count: INV]:
> The reason why we punt is the unexpected _4 != 1 condition, the code
> is prepared to handle just _4 == 0 (or _4 != 0) where _4 == 0 is equivalent
> to _4 != 1 for boolean type.
Hmm, I thought we had code to canonicalize boolean compares (but I can't
find that right now). Some is in
forwprop:forward_propagate_into_gimple_cond where it canonicalizes
!= 1 to == 0.
> The following patch handles even comparison with 1 if the type is
> unsigned 1-bit precision.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok.
Thanks,
Richard.
> 2017-08-03 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/81655
> PR tree-optimization/81588
> * tree-ssa-reassoc.c (optimize_range_tests_var_bound): Handle also
> the case when ranges[i].low and high are 1 for unsigned type with
> precision 1.
>
> --- gcc/tree-ssa-reassoc.c.jj 2017-08-01 10:28:50.000000000 +0200
> +++ gcc/tree-ssa-reassoc.c 2017-08-02 11:28:44.789134681 +0200
> @@ -2918,11 +2918,22 @@ optimize_range_tests_var_bound (enum tre
>
> for (i = 0; i < length; i++)
> {
> + bool in_p = ranges[i].in_p;
> if (ranges[i].low == NULL_TREE
> - || ranges[i].high == NULL_TREE
> - || !integer_zerop (ranges[i].low)
> - || !integer_zerop (ranges[i].high))
> + || ranges[i].high == NULL_TREE)
> continue;
> + if (!integer_zerop (ranges[i].low)
> + || !integer_zerop (ranges[i].high))
> + {
> + if (ranges[i].exp
> + && TYPE_PRECISION (TREE_TYPE (ranges[i].exp)) == 1
> + && TYPE_UNSIGNED (TREE_TYPE (ranges[i].exp))
> + && integer_onep (ranges[i].low)
> + && integer_onep (ranges[i].high))
> + in_p = !in_p;
> + else
> + continue;
> + }
>
> gimple *stmt;
> tree_code ccode;
> @@ -2964,7 +2975,7 @@ optimize_range_tests_var_bound (enum tre
> default:
> continue;
> }
> - if (ranges[i].in_p)
> + if (in_p)
> ccode = invert_tree_comparison (ccode, false);
> switch (ccode)
> {
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
