https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84724
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2018-03-06
CC| |msebor at gcc dot gnu.org
Known to work| |6.4.0
Summary|internal compiler error: in |[7/8 Regression] internal
|single_succ_edge, at |compiler error: in
|basic-block.h:339 |single_succ_edge, at
| |basic-block.h:339 with a
| |declaration of
| |__builtin_trap
Ever confirmed|0 |1
Known to fail| |7.3.0, 8.0
--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Confirmed with r244114 (gcc 7.0.0) as the first revision to ICE:
r244114 | jakub | 2017-01-05 16:14:19 -0500 (Thu, 05 Jan 2017) | 12 lines
PR tree-optimization/71016
Prior to that GCC accepted the test case (with -fpermissive):
t.C:2:5: warning: new declaration ‘int __builtin_trap()’ ambiguates built-in
declaration ‘void __builtin_trap()’ [-Wbuiltin-declaration-mismatch]
int __builtin_trap();
^~~~~~~~~~~~~~
t.C: In function ‘int a()’:
t.C:6:9: warning: invalid conversion from ‘int*’ to ‘int’ [-fpermissive]
int c(&b);
^~
A simpler test case is
int __builtin_trap ();
int a (int i)
{
const char *p = i < 0 ? 0 : "";
return *p;
}
The trouble seems to be that __builtin_trap is expected not to return but the
extern C++ declaration in the program says otherwise and overrides the
built-in. I'd say re-declarations of built-ins that GCC itself depends
on/makes assumptions about should be rejected with a hard error.
