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* [Bug c++/95589] New: missing warning initializing a reference with a dereferenced null @ 2020-06-08 19:25 msebor at gcc dot gnu.org 2020-06-08 19:29 ` [Bug c++/95589] " msebor at gcc dot gnu.org 2021-08-13 8:13 ` egallager at gcc dot gnu.org 0 siblings, 2 replies; 3+ messages in thread From: msebor at gcc dot gnu.org @ 2020-06-08 19:25 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95589 Bug ID: 95589 Summary: missing warning initializing a reference with a dereferenced null Product: gcc Version: 10.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: msebor at gcc dot gnu.org Target Milestone: --- Initializing a reference by dereferenced null pointer is not diagnosed but should be because such a reference is invalid: $ cat t.C && gcc -O2 -S -Wall -Wextra -Wnull-dereference -fdump-tree-optimized=/dev/stdout t.C void f (const int&); void g () { int *p = 0; f (*p); } ;; Function g (_Z1gv, funcdef_no=0, decl_uid=2330, cgraph_uid=1, symbol_order=0) g () { <bb 2> [local count: 1073741824]: f (0B); [tail call] return; } Clang doesn't diagnose it either unless --analyze is used: $ clang -S -Wall -Wextra --analyze t.C t.C:5:3: warning: Forming reference to null pointer f (*p); ^~~~~~ 1 warning generated. ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/95589] missing warning initializing a reference with a dereferenced null 2020-06-08 19:25 [Bug c++/95589] New: missing warning initializing a reference with a dereferenced null msebor at gcc dot gnu.org @ 2020-06-08 19:29 ` msebor at gcc dot gnu.org 2021-08-13 8:13 ` egallager at gcc dot gnu.org 1 sibling, 0 replies; 3+ messages in thread From: msebor at gcc dot gnu.org @ 2020-06-08 19:29 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95589 Martin Sebor <msebor at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- See Also| |https://gcc.gnu.org/bugzill | |a/show_bug.cgi?id=84316 Blocks| |86172 Keywords| |diagnostic --- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> --- I was about to classify this as an enhancement but after reading the description of -Wnull-dereference in the manual ("compiler detects paths that trigger erroneous or undefined behavior due to dereferencing a null pointer") I'm inclined to view it as a bug. The code is clearly in error, GCC just doesn't detect it (even though the "doesn't detect it" part could be used to argue the warning works strictly as documented). Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86172 [Bug 86172] [meta-bug] issues with -Wnull-dereference ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/95589] missing warning initializing a reference with a dereferenced null 2020-06-08 19:25 [Bug c++/95589] New: missing warning initializing a reference with a dereferenced null msebor at gcc dot gnu.org 2020-06-08 19:29 ` [Bug c++/95589] " msebor at gcc dot gnu.org @ 2021-08-13 8:13 ` egallager at gcc dot gnu.org 1 sibling, 0 replies; 3+ messages in thread From: egallager at gcc dot gnu.org @ 2021-08-13 8:13 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95589 Eric Gallager <egallager at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed| |2021-08-13 CC| |egallager at gcc dot gnu.org Status|UNCONFIRMED |NEW Ever confirmed|0 |1 --- Comment #2 from Eric Gallager <egallager at gcc dot gnu.org> --- Confirmed. ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-08-13 8:13 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-06-08 19:25 [Bug c++/95589] New: missing warning initializing a reference with a dereferenced null msebor at gcc dot gnu.org 2020-06-08 19:29 ` [Bug c++/95589] " msebor at gcc dot gnu.org 2021-08-13 8:13 ` egallager at gcc dot gnu.org
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