Bug 955531 – dev-qt/qtbase-6.9.0-r1[custom-cflags]: tst_QRandomGenerator::copyingGlobal() fails with lto

• Status: CONFIRMED
• Product: Gentoo Linux

[Description Ionen Wolkens 2025-05-06 18:09:51 UTC]

Created attachment 927912 [details]
emerge --info and build.log

Was looking at the idea of dropping filter-lto in >=6.9.0 (excl. qtwebengine) given it seems far less broken than before but, at least for qtbase, this one fails for me.

That I can see, LastTest.log only says:

    FAIL!  : tst_QRandomGenerator::copyingGlobal() 'copy != global' returned FALSE. ()
       Loc: [/var/tmp/portage/dev-qt/qtbase-6.9.0-r1/work/qtbase-everywhere-src-6.9.0/tests/auto/corelib/global/qrandomgenerator/tst_qrandomgenerator.cpp(227)]

Does not fail if drop the -flto without changing anything else, does not seem random either (tried a few times). Not planning to debug this myself but putting this here in case anyone wants to look (CC sam). Meanwhile will just leave filter-lto as-is for now so no urgency here.

For convenience test is:

    void tst_QRandomGenerator::copyingGlobal()
    {
        QRandomGenerator &global = *QRandomGenerator::global();
        QRandomGenerator copy = global;
        QCOMPARE(copy, global);
        QCOMPARE(global, copy);

        quint32 samples[20];
        global.fillRange(samples);

        // not equal anymore
        QVERIFY(copy != global);

[Comment 1 Ionen Wolkens 2025-05-06 18:10:17 UTC]

Created attachment 927913 [details]
LastTest.log