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From: "eggert at cs dot ucla.edu" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug analyzer/107565] New: -Wanalyzer-use-of-uninitialized-value false positive with rdrand Date: Tue, 08 Nov 2022 01:15:42 +0000 [thread overview] Message-ID: <bug-107565-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107565 Bug ID: 107565 Summary: -Wanalyzer-use-of-uninitialized-value false positive with rdrand Product: gcc Version: 12.2.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: analyzer Assignee: dmalcolm at gcc dot gnu.org Reporter: eggert at cs dot ucla.edu Target Milestone: --- Created attachment 53846 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53846&action=edit test program illustrating the -fanalyzer false positive This is gcc (GCC) 12.2.1 20220819 (Red Hat 12.2.1-2) on x86-64. Compile the attached program with the command: gcc -O2 -mrdrnd -fanalyzer -S t.c GCC says "warning: use of uninitialized value ‘x’ [CWE-457] [-Wanalyzer-use-of-uninitialized-value]". This is a false positive, as x cannot possibly be uninitialized. Apparently -fanalyzer is confused about how __builtin_ia32_rdrand64_step works. GCC 11.3.0 does not issue this diagnostic, so this is a regression.
next reply other threads:[~2022-11-08 1:15 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-11-08 1:15 eggert at cs dot ucla.edu [this message] 2022-11-08 5:39 ` [Bug target/107565] " pinskia at gcc dot gnu.org 2022-11-08 14:06 ` [Bug target/107565] [12/13 Regression] " dmalcolm at gcc dot gnu.org 2023-01-13 10:19 ` rguenth at gcc dot gnu.org 2023-01-13 12:44 ` [Bug analyzer/107565] " rguenth at gcc dot gnu.org 2023-03-01 14:32 ` dmalcolm at gcc dot gnu.org 2023-03-01 22:26 ` cvs-commit at gcc dot gnu.org 2023-03-01 22:34 ` dmalcolm at gcc dot gnu.org 2023-03-03 23:01 ` [Bug analyzer/107565] [12 " cvs-commit at gcc dot gnu.org 2023-05-08 12:25 ` rguenth at gcc dot gnu.org
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