[Bug c++/81676] Wrong warning with unused-but-set-parameter within 'if constexpr'

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81676

--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Author: mpolacek
Date: Wed Aug 28 02:22:29 2019
New Revision: 274982

URL: https://gcc.gnu.org/viewcvs?rev=274982&root=gcc&view=rev
Log:
        PR c++/81676 - bogus -Wunused warnings in constexpr if.
        * semantics.c (maybe_mark_exp_read_r): New function.
        (finish_if_stmt): Call it on THEN_CLAUSE and ELSE_CLAUSE.

        * g++.dg/cpp1z/constexpr-if31.C: New test.
        * g++.dg/cpp1z/constexpr-if32.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/cpp1z/constexpr-if31.C
    trunk/gcc/testsuite/g++.dg/cpp1z/constexpr-if32.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/semantics.c
    trunk/gcc/testsuite/ChangeLog