https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63368
Bug ID: 63368
Summary: undefined reference to `__sync_val_compare_and_swap_8'
Product: gcc
Version: 4.9.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: mathieu.malaterre at gmail dot com
If I am reading the online documentation properly:
https://gcc.gnu.org/onlinedocs/gcc-4.9.1/gcc/_005f_005fsync-Builtins.html#_005f_005fsync-Builtins
__sync_val_compare_and_swap on some targets will result in a function call
(where direct code generation is not available or not yet implemented).
It seems to be happening in my testcase, however __sync_val_compare_and_swap_8
does not seems to be defined anywhere else.
Steps:
$ cat t.c
#include <stdint.h>
int main()
{
int64_t x = 0, y = 1;
y = __sync_val_compare_and_swap(&x, x, y);
return 0;
}
$ gcc t.c
/tmp/cc6JIpFx.o: In function `main':
t.c:(.text+0x64): undefined reference to `__sync_val_compare_and_swap_8'
collect2: ld returned 1 exit status
$ gcc t.c -lgcc_s
/tmp/ccu3ReMZ.o: In function `main':
t.c:(.text+0x64): undefined reference to `__sync_val_compare_and_swap_8'
collect2: ld returned 1 exit status
$ gcc t.c -lgcc
/tmp/ccO8gyeR.o: In function `main':
t.c:(.text+0x64): undefined reference to `__sync_val_compare_and_swap_8'
collect2: ld returned 1 exit status
