http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59676
Bug ID: 59676
Summary: Non-integral glvalues accepted in constant expressions
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ville.voutilainen at gmail dot com
constexpr int foo(float f) {return int(f);}
int main()
{
const float x = 0.5;
static_assert(x > 0.1, "all good"); // #1
constexpr int i = foo(x); // #2
}
gcc accepts this, clang doesn't accept either #1 or #2.
[expr.const]/2 bullet 7, sub-bullet 1 says
"a non-volatile glvalue of integral or enumeration type that refers to a
non-volatile const object with
a preceding initialization, initialized with a constant expression".
It looks to me as if we have a non-volatile glvalue of a non-integral
type, so x and (x>0.1) are not constant expressions, and static_assert
and the initialization of i shouldn't allow using x.
