https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85474
Bug ID: 85474
Summary: unspecified string literal comparison accepted in
constexpr context
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
According to [expr.const]:
An expression e is a core constant expression unless the evaluation of e,
following the rules of the abstract machine (4.6), would evaluate one of the
following expressions:
...
-- a relational (8.9) or equality (8.10) operator where the result is
unspecified;
That means that the following program is ill-formed and needs to be rejected
with an error:
$ cat t.C && gcc -S -Wall -Wextra -Wpedantic t.C
constexpr bool b = "" == "";
t.C:1:26: warning: comparison with string literal results in unspecified
behavior [-Waddress]
constexpr bool b = "" == "";
^~
GCC accepts the program with only a warning when it should reject it with a
hard error as Clang does.
