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Subject: [Bug c/106264] [10/11/12/13 Regression] spurious -Wunused-value on a
 folded frexp, modf, and remquo calls with unused result since
 r9-1295-g781ff3d80e88d7d0
Date: Tue, 19 Jul 2022 07:40:39 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106264

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Roger Sayle <sayle@gcc.gnu.org>:

https://gcc.gnu.org/g:40f6e5912288256ee8ac41474f2dce7b6881c111

commit r13-1741-g40f6e5912288256ee8ac41474f2dce7b6881c111
Author: Roger Sayle <roger@nextmovesoftware.com>
Date:   Tue Jul 19 08:39:43 2022 +0100

    PR c/106264: Silence warnings from __builtin_modf et al.

    This middle-end patch resolves PR c/106264 which is a spurious warning
    regression caused by the tree-level expansion of modf, frexp and remquo
    producing "expression has no-effect" when the built-in function's result
    is ignored.  When these built-ins were first expanded at tree-level,
    fold_builtin_n would blindly set TREE_NO_WARNING for all built-ins. Now
    that we're more discerning, we should precisely call suppress_warning
    selectively on those COMPOUND_EXPRs that need them.

    2022-07-19  Roger Sayle  <roger@nextmovesoftware.com>
                Richard Biener  <rguenther@suse.de>

    gcc/ChangeLog
            PR c/106264
            * builtins.cc (fold_builtin_frexp): Call suppress_warning on
            COMPOUND_EXPR to silence spurious warning if result isn't used.
            (fold_builtin_modf): Likewise.
            (do_mpfr_remquo): Likewise.

    gcc/testsuite/ChangeLog
            PR c/106264
            * gcc.dg/pr106264.c: New test case.=