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* [Bug c++/102335] New: gcc misses -Wunused-value @ 2021-09-14 18:11 vanyacpp at gmail dot com 2021-09-14 18:15 ` [Bug c++/102335] " pinskia at gcc dot gnu.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: vanyacpp at gmail dot com @ 2021-09-14 18:11 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102335 Bug ID: 102335 Summary: gcc misses -Wunused-value Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: vanyacpp at gmail dot com Target Milestone: --- struct mytype { int memfun [[gnu::pure]] (); }; void test() { mytype x; x.memfun(); // -Wunused-value mytype().memfun(); // no -Wunused-value } https://godbolt.org/z/vc49jWGqn The code above contains two usages of a [[gnu::pure]] function with ignored return value. GCC detect only the first one. I believe the second one deserves a warning too. Clang shows a warning on both usages. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/102335] gcc misses -Wunused-value 2021-09-14 18:11 [Bug c++/102335] New: gcc misses -Wunused-value vanyacpp at gmail dot com @ 2021-09-14 18:15 ` pinskia at gcc dot gnu.org 2021-09-14 18:17 ` pinskia at gcc dot gnu.org 2021-09-15 8:03 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-09-14 18:15 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102335 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Severity|normal |minor Keywords| |diagnostic ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/102335] gcc misses -Wunused-value 2021-09-14 18:11 [Bug c++/102335] New: gcc misses -Wunused-value vanyacpp at gmail dot com 2021-09-14 18:15 ` [Bug c++/102335] " pinskia at gcc dot gnu.org @ 2021-09-14 18:17 ` pinskia at gcc dot gnu.org 2021-09-15 8:03 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-09-14 18:17 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102335 --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Internal GCC details: Most likely because there is a TARGET_EXPR in the IR which causes it to be considered a side effect: <<cleanup_point <<< Unknown tree: expr_stmt (void) mytype::memfun (&TARGET_EXPR <D.2411, {}>) >>>>>; ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/102335] gcc misses -Wunused-value 2021-09-14 18:11 [Bug c++/102335] New: gcc misses -Wunused-value vanyacpp at gmail dot com 2021-09-14 18:15 ` [Bug c++/102335] " pinskia at gcc dot gnu.org 2021-09-14 18:17 ` pinskia at gcc dot gnu.org @ 2021-09-15 8:03 ` rguenth at gcc dot gnu.org 2 siblings, 0 replies; 4+ messages in thread From: rguenth at gcc dot gnu.org @ 2021-09-15 8:03 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102335 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Status|UNCONFIRMED |NEW Last reconfirmed| |2021-09-15 ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-09-15 8:03 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-09-14 18:11 [Bug c++/102335] New: gcc misses -Wunused-value vanyacpp at gmail dot com 2021-09-14 18:15 ` [Bug c++/102335] " pinskia at gcc dot gnu.org 2021-09-14 18:17 ` pinskia at gcc dot gnu.org 2021-09-15 8:03 ` rguenth at gcc dot gnu.org
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