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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/99536] unexplained warning on "uninitialized value" in std::normal_distribution
Date: Thu, 11 Mar 2021 13:30:35 +0000 [thread overview]
Message-ID: <bug-99536-4-1I39bJ8SZj@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-99536-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99536
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
GCC 5 is old and no longer supported.
This is probably a jump threading bug. The _M_saved member is only ever used if
_M_saved_available says it can be used, and that is only the case after it's
been initialized.
We could probably just initialize it on construction to avoid the false
positive warning:
--- a/libstdc++-v3/include/bits/random.h
+++ b/libstdc++-v3/include/bits/random.h
@@ -2024,12 +2024,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
explicit
normal_distribution(result_type __mean,
result_type __stddev = result_type(1))
- : _M_param(__mean, __stddev), _M_saved_available(false)
+ : _M_param(__mean, __stddev)
{ }
explicit
normal_distribution(const param_type& __p)
- : _M_param(__p), _M_saved_available(false)
+ : _M_param(__p)
{ }
/**
@@ -2166,8 +2166,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
const param_type& __p);
param_type _M_param;
- result_type _M_saved;
- bool _M_saved_available;
+ result_type _M_saved = 0;
+ bool _M_saved_available = false;
};
/**
next prev parent reply other threads:[~2021-03-11 13:30 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-11 1:36 [Bug c++/99536] New: unexplained warning on "uninitialized value" wuz73 at hotmail dot com
2021-03-11 13:30 ` redi at gcc dot gnu.org [this message]
2021-03-11 15:09 ` [Bug c++/99536] unexplained warning on "uninitialized value" in std::normal_distribution redi at gcc dot gnu.org
2021-03-11 17:53 ` cvs-commit at gcc dot gnu.org
2021-03-11 18:18 ` redi at gcc dot gnu.org
2021-03-29 20:03 ` cvs-commit at gcc dot gnu.org
2021-03-29 21:37 ` redi at gcc dot gnu.org
2021-04-07 21:16 ` [Bug tree-optimization/99536] " msebor at gcc dot gnu.org
2021-04-07 21:18 ` msebor at gcc dot gnu.org
2021-04-20 18:52 ` cvs-commit at gcc dot gnu.org
2022-08-06 2:57 ` wuz73 at hotmail dot com
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