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* [Bug c++/94265] New: wrong warning "duplicated 'if' condition"
@ 2020-03-23 0:38 f.heckenbach@fh-soft.de
2020-03-23 8:05 ` [Bug c++/94265] " marxin at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: f.heckenbach@fh-soft.de @ 2020-03-23 0:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94265
Bug ID: 94265
Summary: wrong warning "duplicated 'if' condition"
Product: gcc
Version: 9.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: f.heckenbach@fh-soft.de
Target Milestone: ---
% cat t.cpp
#include <tuple>
struct S { int a, b; };
int main ()
{
if (auto [a,b] = S { 0, 1 }; a) { }
else if (std::tie (a, b) = std::tuple (2, 3); a) { }
}
% g++ -std=c++17 -Wduplicated-cond t.cpp
t.cpp: In function 'int main()':
t.cpp:8:8: warning: duplicated 'if' condition [-Wduplicated-cond]
8 | else if (std::tie (a, b) = std::tuple (2, 3); a) { }
| ^~
t.cpp:7:3: note: previously used here
7 | if (auto [a,b] = S { 0, 1 }; a) { }
| ^~
Though the condition "a" looks the same in both "if" statements, the value of a
can change in between, and in fact does in this example (the second "if" branch
is actually taken).
Unless the "tie" assignment to "auto []" pseudo-variables is for some reason
incorrect, but then of course gcc should mention that.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/94265] wrong warning "duplicated 'if' condition"
2020-03-23 0:38 [Bug c++/94265] New: wrong warning "duplicated 'if' condition" f.heckenbach@fh-soft.de
@ 2020-03-23 8:05 ` marxin at gcc dot gnu.org
2020-03-24 17:18 ` ppalka at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: marxin at gcc dot gnu.org @ 2020-03-23 8:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94265
Martin Liška <marxin at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Last reconfirmed| |2020-03-23
CC| |marxin at gcc dot gnu.org
--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/94265] wrong warning "duplicated 'if' condition"
2020-03-23 0:38 [Bug c++/94265] New: wrong warning "duplicated 'if' condition" f.heckenbach@fh-soft.de
2020-03-23 8:05 ` [Bug c++/94265] " marxin at gcc dot gnu.org
@ 2020-03-24 17:18 ` ppalka at gcc dot gnu.org
2020-03-25 16:35 ` cvs-commit at gcc dot gnu.org
2020-03-25 16:37 ` ppalka at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: ppalka at gcc dot gnu.org @ 2020-03-24 17:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94265
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |ppalka at gcc dot gnu.org
CC| |ppalka at gcc dot gnu.org
Status|NEW |ASSIGNED
--- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Taking a look.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/94265] wrong warning "duplicated 'if' condition"
2020-03-23 0:38 [Bug c++/94265] New: wrong warning "duplicated 'if' condition" f.heckenbach@fh-soft.de
2020-03-23 8:05 ` [Bug c++/94265] " marxin at gcc dot gnu.org
2020-03-24 17:18 ` ppalka at gcc dot gnu.org
@ 2020-03-25 16:35 ` cvs-commit at gcc dot gnu.org
2020-03-25 16:37 ` ppalka at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2020-03-25 16:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94265
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:
https://gcc.gnu.org/g:c7a252ba2d0a08397d8fc6d6dc7db34f90f76acb
commit r10-7379-gc7a252ba2d0a08397d8fc6d6dc7db34f90f76acb
Author: Patrick Palka <ppalka@redhat.com>
Date: Wed Mar 25 12:32:43 2020 -0400
c++: Fix invalid -Wduplicated-cond warning [PR94265]
This fixes a false-positive warning from -Wduplicate-cond in the presence
of an
if-statement with a non-empty init-statement. Precisely determining
whether a
non-empty init-statement has side effects seems tricky and error-prone, so
this
patch takes the route of unconditionally invalidating the condition chain
when
it encounters such an if-statement.
gcc/cp/ChangeLog:
PR c++/94265
* parser.c (cp_parser_selection_statement) <case RID_IF>:
Invalidate the
current condition chain when the if-statement has a non-empty
init-statement.
gcc/testsuite/ChangeLog:
PR c++/94265
* g++.dg/warn/Wduplicated-cond1.C: New test.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/94265] wrong warning "duplicated 'if' condition"
2020-03-23 0:38 [Bug c++/94265] New: wrong warning "duplicated 'if' condition" f.heckenbach@fh-soft.de
` (2 preceding siblings ...)
2020-03-25 16:35 ` cvs-commit at gcc dot gnu.org
@ 2020-03-25 16:37 ` ppalka at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: ppalka at gcc dot gnu.org @ 2020-03-25 16:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94265
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
Target Milestone|--- |10.0
--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Thanks for the bug report, this is now fixed for GCC 10.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-03-25 16:37 UTC | newest]
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2020-03-23 0:38 [Bug c++/94265] New: wrong warning "duplicated 'if' condition" f.heckenbach@fh-soft.de
2020-03-23 8:05 ` [Bug c++/94265] " marxin at gcc dot gnu.org
2020-03-24 17:18 ` ppalka at gcc dot gnu.org
2020-03-25 16:35 ` cvs-commit at gcc dot gnu.org
2020-03-25 16:37 ` ppalka at gcc dot gnu.org
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