https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121613
Bug ID: 121613
Summary: Support for named address spaces is broken on x32
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: ubizjak at gmail dot com
Target Milestone: ---
The following testcase:
--cut here--
extern const long __rseq_offset;
struct rseq_area
{
int a;
int b;
int c;
};
int read_rseq (void)
{
int val = (*(volatile int __seg_fs *)
(__rseq_offset + __builtin_offsetof (struct rseq_area, c)));
return val;
}
--cut here--
compiles with -O2 -mx32 to:
read_rseq:
movl __rseq_offset(%rip), %eax
movl %fs:8(%eax), %eax
ret
This code will segfault when offset in "%fs:off" is negative, because address
"%fs:off" is calculated as:
EffectiveAddress = FS.base + ZeroExtend32(off)
