https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100498
Bug ID: 100498
Summary: SFINAE and static inline function
Product: gcc
Version: 7.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: [email protected]
Target Milestone: ---
Hi,
I would like to post a bug report for the GNU C/C++ compiler 7.5.0.
We use the compiler to generate code for a PowerPC processor.
Invokation line for the GNU C++ compiler:
ccppc -c -x c++ --std=gnu++17 -Wall -Werror -g -mcpu=e6500 -m32
-maltivec -mvrsave -ftls-model=local-exec -msdata=sysv
-fno-common -fno-openmp -mbig -mmultiple -mno-string -misel
-mstrict-align -fverbose-asm -G 8 -O3
-I<some include paths>
-D<some #define's>
X.CPP -oX.O
// file X.CPP
void f1 (int) {}
inline void f1 (float) {}
struct X
{
friend void f1 (int*) {}
};
void f1 (int*);
template <typename F_, typename = void>
struct SFINAE
{ static constexpr F_* ptr = nullptr; };
template <typename F_>
struct SFINAE< F_, decltype((void)static_cast<F_*>(f1), void()) >
{ static constexpr F_* ptr = f1; };
void func ()
{
using F1 = void(int);
constexpr F1* ptr1{ SFINAE<F1>::ptr };
static_assert (ptr1 != nullptr);
using F2 = void(float);
constexpr F2* ptr2{ SFINAE<F2>::ptr };
static_assert (ptr2 != nullptr);
using F3 = void(int*);
constexpr F3* ptr3{ SFINAE<F3>::ptr };
static_assert (ptr3 != nullptr);
}
Wenn we compile this program we get the following error messages:
x.CPP: In function 'void func()':
x.CPP:29:5: error: non-constant condition for static assertion
static_assert (ptr2 != nullptr);
^~~~~~~~~~~~~
x.CPP:29:25: error: '(f1 != 0)' is not a constant expression
static_assert (ptr2 != nullptr);
~~~~~^~~~~~~~~~
x.CPP:33:5: error: non-constant condition for static assertion
static_assert (ptr3 != nullptr);
^~~~~~~~~~~~~
x.CPP:33:25: error: '(f1 != 0)' is not a constant expression
static_assert (ptr3 != nullptr);
~~~~~^~~~~~~~~~
The reason for the first error messages is the inline attribute of function
"void f1 (float)"; the error messages disappear if "inline" is removed. I
I think this is not standard compliant.
A similar problem seems to arise with function "void f1 (int*)".
With kind regards
W. Roehrl
