[Bug ipa/110334] [13/14 Regresssion] unused functions not eliminated before LTO streaming

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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110334

--- Comment #17 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jan Hubicka <hubicka@gcc.gnu.org>:

https://gcc.gnu.org/g:d88fd2e1d0720e6f892da9ff48e9a301a7ad0ad4

commit r14-2172-gd88fd2e1d0720e6f892da9ff48e9a301a7ad0ad4
Author: Jan Hubicka <jh@suse.cz>
Date:   Wed Jun 28 23:05:28 2023 +0200

    Enable early inlining into always_inline functions

    Early inliner currently skips always_inline functions and moreover we
ignore
    calls from always_inline in ipa_reverse_postorder.  This leads to disabling
    most of propagation done using early optimization that is quite bad when
    early inline functions are not leaf functions, which is now quite common
    in libstdc++.

    This patch instead of fully disabling the inline checks calls in callee.
    I am quite conservative about what can be inlined as this patch is bit
    touchy anyway.  To avoid problems with always_inline being optimized
    after early inline I extended inline_always_inline_functions to lazilly
    compute fnsummary when needed.

    gcc/ChangeLog:

            PR middle-end/110334
            * ipa-fnsummary.h (ipa_fn_summary): Add
            safe_to_inline_to_always_inline.
            * ipa-inline.cc (can_early_inline_edge_p): ICE
            if SSA is not built; do cycle checking for
            always_inline functions.
            (inline_always_inline_functions): Be recrusive;
            watch for cycles; do not updat overall summary.
            (early_inliner): Do not give up on always_inlines.
            * ipa-utils.cc (ipa_reverse_postorder): Do not skip
            always inlines.

    gcc/testsuite/ChangeLog:

            PR middle-end/110334
            * g++.dg/opt/pr66119.C: Disable early inlining.
            * gcc.c-torture/compile/pr110334.c: New test.
            * gcc.dg/tree-ssa/pr110334.c: New test.