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From: "vincent-gcc at vinc17 dot net" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/107839] New: spurious "may be used uninitialized" warning while all uses are under "if (c)" Date: Wed, 23 Nov 2022 16:38:14 +0000 [thread overview] Message-ID: <bug-107839-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107839 Bug ID: 107839 Summary: spurious "may be used uninitialized" warning while all uses are under "if (c)" Product: gcc Version: 13.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: vincent-gcc at vinc17 dot net Target Milestone: --- Consider int f (int); void g (int c) { int v; if (c) v = f(0); while (1) if (c) f(v + v); } $ gcc-test -O -Wmaybe-uninitialized -c tst2.c tst2.c: In function ‘g’: tst2.c:4:7: warning: ‘v’ may be used uninitialized [-Wmaybe-uninitialized] 4 | int v; | ^ All uses of v are under "if (c)", so the warning is incorrect. Note that replacing "v + v" by "v" makes the warning disappear. This occurs with GCC 8.4.0 and above up to at least 13.0.0 20220906 (experimental) from the master branch. No warnings with GCC 6.5.0 and below. Note to myself (to check once this bug is fixed): this testcase is derived from tmd/binary32/hrcases.c (warning on variable t0).
next reply other threads:[~2022-11-23 16:38 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-11-23 16:38 vincent-gcc at vinc17 dot net [this message] 2022-11-23 21:00 ` [Bug tree-optimization/107839] " rguenth at gcc dot gnu.org 2022-11-24 10:12 ` rguenth at gcc dot gnu.org 2022-11-24 17:09 ` vincent-gcc at vinc17 dot net 2022-12-05 9:32 ` cvs-commit at gcc dot gnu.org 2022-12-05 9:47 ` rguenth at gcc dot gnu.org 2022-12-12 11:20 ` cvs-commit at gcc dot gnu.org 2024-01-20 17:22 ` pinskia at gcc dot gnu.org
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