https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99211
Bug ID: 99211
Summary: gcc fails on program which overrides __builtin_clzll
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: zhan3299 at purdue dot edu
Target Milestone: ---
GCC fails to compile the attached code: https://godbolt.org/z/sdqq3M
One interesting thing is that, only when we override __builtin_clzll this issue
will occur. If we replace the __builtin_clzll as any other builtin function
(e.g., __builtin_expect), GCC will accept the program with a conflicting type
warning: https://godbolt.org/z/5c45T6
For other compilers,
Clang rejects such conflicts with built-in functions:
https://godbolt.org/z/9WzTKP
Icc accepts and successfully compiles it (with warnings):
https://godbolt.org/z/W4zK89
$ cat test.c
struct S {
int a;
};
struct S __builtin_clzll(long x) {
if (x == 1) {
struct S y = { .a = 1 };
return y;
} else {
struct S y = { .a = __builtin_clzll(1).a + 1 };
return y;
}
}
int main() {
return __builtin_clzll(10).a;
}
$ gcc test.c
test.c: In function '__builtin_clzll':
test.c:10:16: internal compiler error: in wide_int_to_tree_1, at tree.c:1644
10 | struct S y = { .a = __builtin_clzll(1).a + 1 };
| ^
0x1a31d99 internal_error(char const*, ...)
???:0
0x6877ad fancy_abort(char const*, int, char const*)
???:0
0x9bed4a fold_build_call_array_loc(unsigned int, tree_node*, tree_node*, int,
tree_node**)
???:0
0x6e1010 build_function_call_vec(unsigned int, vec<unsigned int, va_heap,
vl_ptr>, tree_node*, vec<tree_node*, va_gc, vl_embed>*, vec<tree_node*, va_gc,
vl_embed>*, tree_node*)
???:0
0x7322e9 c_parse_file()
???:0
0x7a02c2 c_common_parse_file()
???:0
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
