On 10/27/22 23:47, Sebastian Huber wrote:
On 28/10/2022 01:05, Palmer Dabbelt wrote:
On Thu, 27 Oct 2022 15:56:17 PDT (-0700), gcc-patches@gcc.gnu.org wrote:
On 10/26/22 01:49, Sebastian Huber wrote:
The RV32A extension does not support 64-bit atomic operations. For
RTEMS, use
a 32-bit gcov type for RV32.
gcc/ChangeLog:
* config/riscv/riscv.cc (riscv_gcov_type_size): New.
(TARGET_GCOV_TYPE_SIZE): Likewise.
* config/riscv/rtems.h (RISCV_GCOV_TYPE_SIZE): New.
Why make this specific to rtems? ISTM the logic behind this change
would apply independently of the os.
Reducing the gcov type to 32-bit has the drawback that the program
runtime is reduced. I am not sure if this is generally acceptable.
Right, but if you're limited by RV32A, then we're architecturally
limited to 32bit atomics. So something has to give.
I'm not objecting to this for rtems. I'm just noting that if we're
dealing with an architectural limitation, then the issue is likely to
show up in other operating systems, so we should at least ponder if we
want to do an OS specific change or something more general.
Jeff
