[Bug c/112826] gcc rejects the valid code and reports undefined reference
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112826 --- Comment #4 from Junwei Zeng --- Thank you for your explanation.
[Bug c/112826] gcc rejects the valid code and reports undefined reference
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112826 Andrew Pinski changed: What|Removed |Added See Also||https://gcc.gnu.org/bugzill ||a/show_bug.cgi?id=14105 --- Comment #3 from Andrew Pinski --- Note PR 14105 is the opposite request but both are invalid as both behavior with and without optimization is allowed by the C standard.
[Bug c/112826] gcc rejects the valid code and reports undefined reference
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112826 Xi Ruoyao changed: What|Removed |Added Resolution|--- |INVALID Status|UNCONFIRMED |RESOLVED CC||xry111 at gcc dot gnu.org --- Comment #2 from Xi Ruoyao --- N1570 6.9 p2: "If an identifier declared with external linkage is used in an expression (other than as part of the operand of a sizeof or _Alignof operator whose result is an integer constant), somewhere in the entire program there shall be exactly one external definition for the identifier" and annex J.2 explicitly lists "An identifier with external linkage is used, but in the program there does not exist exactly one external definition for the identifier" as undefined behavior. Note that you cannot interpret "used" as "really executed at runtime" because it's impossible to solve halting problem, so such an "interpretation" will render the entire standard nonsense.
[Bug c/112826] gcc rejects the valid code and reports undefined reference
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112826 Arsen Arsenović changed: What|Removed |Added CC||arsen at gcc dot gnu.org --- Comment #1 from Arsen Arsenović --- I can't assert the validity of this code, but -O1 does elide the function as expected.
