This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [C++ PATCH] Handle CASE_HIGH in constexpr evaluation (PR c++/72868)
- From: Jason Merrill <jason at redhat dot com>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: gcc-patches List <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 11 Aug 2016 11:46:14 -0400
- Subject: Re: [C++ PATCH] Handle CASE_HIGH in constexpr evaluation (PR c++/72868)
- Authentication-results: sourceware.org; auth=none
- References: <20160811145516.GS14857@tucnak.redhat.com>
OK for trunk and 6.
On Thu, Aug 11, 2016 at 10:55 AM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> As mentioned in the PR, constexpr.c has been handling cases with ranges
> just as the lowest value of the range.
>
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk? What about 6.2 (not a regression, but low risk fix for wrong-code)?
>
> 2016-08-11 Jakub Jelinek <jakub@redhat.com>
>
> PR c++/72868
> * constexpr.c (label_matches): Handle case range expressions.
>
> * g++.dg/cpp1y/constexpr-switch4.C: New test.
>
> --- gcc/cp/constexpr.c.jj 2016-08-10 00:21:07.000000000 +0200
> +++ gcc/cp/constexpr.c 2016-08-10 22:17:16.577041975 +0200
> @@ -3448,6 +3448,12 @@ label_matches (tree *jump_target, tree_s
> {
> if (!CASE_LOW (stmt))
> default_label = i;
> + else if (CASE_HIGH (stmt))
> + {
> + if (tree_int_cst_le (CASE_LOW (stmt), *jump_target)
> + && tree_int_cst_le (*jump_target, CASE_HIGH (stmt)))
> + return true;
> + }
> else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt)))
> return true;
> }
> --- gcc/testsuite/g++.dg/cpp1y/constexpr-switch4.C.jj 2016-08-10 22:22:29.567129868 +0200
> +++ gcc/testsuite/g++.dg/cpp1y/constexpr-switch4.C 2016-08-10 22:23:25.104435699 +0200
> @@ -0,0 +1,27 @@
> +// PR c++/72868
> +// { dg-do compile }
> +// { dg-options "-std=gnu++14" }
> +
> +constexpr int
> +foo (int i)
> +{
> + switch (i)
> + {
> + case 11 ... 12:
> + return 4;
> + case 0 ... 9:
> + return 3;
> + default:
> + return 7;
> + }
> +}
> +
> +#define SA(X) static_assert((X),#X)
> +SA (foo (-1) == 7);
> +SA (foo (0) == 3);
> +SA (foo (3) == 3);
> +SA (foo (9) == 3);
> +SA (foo (10) == 7);
> +SA (foo (11) == 4);
> +SA (foo (12) == 4);
> +SA (foo (13) == 7);
>
> Jakub