https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118488
Bug ID: 118488
Summary: [OpenMP] Return types and templates with 'declare
variant' mishandled
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Keywords: openmp, rejects-valid
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: burnus at gcc dot gnu.org
Target Milestone: ---
Cf. discussion at OpenMP spec Issue 4371.
The following code compiles with clang++-19 but is rejected by GCC;
the current thought is that it is supposed to be valid.
(Even if at the end the substitution would be invalid like in:
myClass var3();
#pragma omp declare variant(var3) match(...)
template<typename T3>
base3 ();
when being called with "int x = base3<int>();". See also PR118486.)
* * *
template<typename T2>
T2 expl1();
int expl2();
#pragma omp declare variant(expl1) match(user={condition(true)})
#pragma omp declare variant(expl2) match(user={condition(true)})
template<typename T>
T base();
void f() {
int x;
x = base<int>();
}
GCC rejects it with:
error: variant ‘int expl2()’ and base ‘T base()’ have incompatible types
and
error: no matching function for call to ‘expl1()’
note: candidate: ‘template<class T2> T2 expl1()’
note: template argument deduction/substitution failed:
note: couldn’t deduce template parameter ‘T2’
