https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99287
Bug ID: 99287
Summary: std::source_location::function_name breaks constexpr
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: nickgray0 at brown dot edu
Target Milestone: ---
the following code seems to break constexpr-ness for std::string_view::find
#include <source_location>
#include <string_view>
template<typename>
consteval auto f() {
return std::string_view{
std::source_location::current().function_name() };
}
auto main()->int {
constexpr auto s = f<int>();
constexpr auto x = s.find("int");
}
error message: In file included from
/opt/compiler-explorer/gcc-trunk-20210226/include/c++/11.0.1/string_view:781,
from <source>:2:
/opt/compiler-explorer/gcc-trunk-20210226/include/c++/11.0.1/bits/string_view.tcc:
In function 'int main()':
<source>:11:30: in 'constexpr' expansion of
's.std::basic_string_view<char>::find(((const char*)"int"), 0)'
/opt/compiler-explorer/gcc-trunk-20210226/include/c++/11.0.1/string_view:384:26:
in 'constexpr' expansion of '((const
std::basic_string_view<char>*)this)->std::basic_string_view<char>::find(__str,
__pos, std::char_traits<char>::length(__str))'
/opt/compiler-explorer/gcc-trunk-20210226/include/c++/11.0.1/bits/string_view.tcc:62:20:
error: '(((std::basic_string_view<char>::size_type)((&"consteval auto f() [with
<template-parameter-1-1> = int]"[56]) - ((&"consteval auto f() [with
<template-parameter-1-1> = int]"[21]) + 1))) > 2)' is not a constant expression
62 | while (__len >= __n)
| ~~~~~~^~~~~~
Replacing std::source_location with the legacy
std::experimental::source_location seems to fix the problem.
