https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91901
Bug ID: 91901
Summary: constexpr stack array not optimized away
Product: gcc
Version: 9.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: trass3r at gmail dot com
Target Milestone: ---
Created attachment 46940
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46940&action=edit
full test code
#include
<https://github.com/Neargye/magic_enum/raw/master/include/magic_enum.hpp>
enum class E
{
E00, E01, E02, E03, E04, E05, E06, E07, E08, E09,
E10, E11, E12, E13, E14, E15, E16, E17, E18, E19,
E20, E21, E22, E23, E24, E25, E26, E27, E28, E29,
E30, E31, E32, E33, E34, E35, E36, E37, E38, E39,
E40, E41, E42, E43, E44, E45, E46, E47, E48, E49,
E50, E51, E52, E53, E54, E55, E56, E57, E58, E59,
E60, E61, E62, E63,
};
#include <cstdio>
void test(Color c)
{
auto name = magic_enum::enum_name(c);
printf(name.data());
}
$ g++ -O2 -std=c++2a
It generates the lookup table in .rodata but then still copies it to the stack
inside name<E>(E): https://godbolt.org/z/cDp30l
Remove E63 to see the initialization being completely inlined, potentially
resulting in even larger code.
