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From: "bug-apl at gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/94905] New: Bogus warning -Werror=maybe-uninitialized Date: Fri, 01 May 2020 16:25:02 +0000 [thread overview] Message-ID: <bug-94905-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94905 Bug ID: 94905 Summary: Bogus warning -Werror=maybe-uninitialized Product: gcc Version: 9.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: bug-apl at gnu dot org Target Milestone: --- Hi, as of g++ 9.3.0 when building GNU APL, g++ emits bogus warnings of type -Werror=maybe-uninitialized. Apparently the compiler issues these warnings simply because it is lacking enough context to really figure out what is happening (e.g. if the supposedly missing initialization is happening in a different function). An example is: https://svn.savannah.gnu.org/viewvc/apl/trunk/src/Shape.hh?view=markup Shape.hh:133:18: error: ‘shape_Z.Shape::rho[axis]’ may be used uninitialized in this function [-Werror=maybe-uninitialized] if (rho[r]) { volume /= rho[r]; rho[r] = sh; volume *= rho[r]; } ~~~~~^ The line 133 is preceded by an assertion that verifies that rho[r] is initialized. Apparently the compiler assumes that the initialization of rho[r] on the right of = happens after the test of rho[r] on the left of =. It completely ignores, however, the fact that rho[r] was simply updated and was initialized already before the function (set_shape_item) was called. May I kindly request to move this kind of warnings away from -Wall to -Wextra ? According to "man g++": -Wall This enables all the warnings about constructions that some users consider questionable, and that are easy to avoid (or modify to prevent the warning), even in conjunction with macros. This also In the example above there is no "easy to avoid" way to fix the warning. Kind regards, Jürgen Sauermann Maintainer of GNU APL
next reply other threads:[~2020-05-01 16:25 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-05-01 16:25 bug-apl at gnu dot org [this message] 2020-05-01 22:41 ` [Bug c++/94905] " glisse at gcc dot gnu.org 2020-05-03 13:28 ` bug-apl at gnu dot org 2020-05-03 15:02 ` asolokha at gmx dot com 2020-05-03 16:10 ` bug-apl at gnu dot org 2020-05-03 16:16 ` bug-apl at gnu dot org 2020-05-03 16:26 ` asolokha at gmx dot com 2020-07-02 15:47 ` moller at mollerware dot com 2020-07-02 15:51 ` moller at mollerware dot com 2020-09-03 18:34 ` manu at gcc dot gnu.org 2020-09-03 18:46 ` [Bug c++/94905] [10 Regression] " manu at gcc dot gnu.org 2021-04-08 16:34 ` [Bug tree-optimization/94905] [10/11 " jason at gcc dot gnu.org 2022-01-21 13:41 ` rguenth at gcc dot gnu.org 2022-01-21 13:41 ` rguenth at gcc dot gnu.org 2022-01-21 13:43 ` rguenth at gcc dot gnu.org 2022-01-31 14:50 ` marxin at gcc dot gnu.org 2022-04-07 9:39 ` rguenth at gcc dot gnu.org 2022-04-07 10:01 ` jakub at gcc dot gnu.org 2022-06-28 10:40 ` jakub at gcc dot gnu.org 2023-07-07 10:37 ` [Bug tree-optimization/94905] [11 " rguenth at gcc dot gnu.org
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