https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108395
Bug ID: 108395
Summary: [C2x] Bogus -Wunused-but-set-variable when returning
constexpr variable
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: p...@gcc-bugzilla.mail.kapsi.fi
Target Milestone: ---
Hi.
It appears if constexpr variable, declared at block scope, is used verbatim as
a return value GCC emits a bogus -Wunused-but-set-variable.
Using version `13.0.0 20230113 (experimental)'.
# echo 'int f() { constexpr int v = 0; return v; }' | gcc -c -xc -std=c2x -Wall
-Wextra -
<stdin>: In function 'f':
<stdin>:1:25: warning: variable 'v' set but not used
[-Wunused-but-set-variable]
As a workaround any operation on v (cast, effectively-no-op arithmetics etc.)
or maybe_unused attribute (or file scope) can be used.
