The following test case is accepted by 3.3 (both C and C++) and by 4.0 C, but
not by 4.0 C++.
#define FOO(x) (__builtin_constant_p(x) ? 1 : 2)
int foo(int n) {
switch(n) {
case FOO(3):
return 1;
default:
return 2;
}
}
Was this change intentional? Even if it was, the C/C++ incompatibility is
unfortunate. This sort of
construct is likely to appear in headers used by both languages. (And we can't
very well point to
language standards in deciding whether __builtin_constant_p should be
considered a constant-
expression, since it's a GNU extension.)
--
Summary: g++ no longer accepts __builtin_constant_p in constant-
expressions
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: austern at apple dot com
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: powerpc-apple-darwin7.7.0
GCC host triplet: powerpc-apple-darwin7.7.0
GCC target triplet: powerpc-apple-darwin7.7.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19628
