https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107403
Bug ID: 107403
Summary: uint64_t bitfield operation is mishandled
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
Target Milestone: ---
Target: x84
[hjl@gnu-cfl-1 tmp]$ cat foo.c
#include <stdint.h>
#include <stdio.h>
#define VAL (1ULL << 48)
struct foo
{
uint64_t x : 8;
uint64_t y : 56;
};
__attribute__ ((noinline))
uint64_t
func (struct foo i)
{
return i.y << 8ULL;
}
int
main ()
{
struct foo i;
i.x = 0;
i.y = VAL;
uint64_t x = func (i);
printf ("0x%llx\n", x);
printf ("0x%llx\n", VAL);
if (x != (VAL << 8ULL))
__builtin_abort ();
}
[hjl@gnu-cfl-1 tmp]$ gcc foo.c
[hjl@gnu-cfl-1 tmp]$ ./a.out
0x0
0x1000000000000
Aborted (core dumped)
[hjl@gnu-cfl-1 tmp]$
