https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104580
Bug ID: 104580
Summary: [nvptx] Use prevent_branch_around_nothing only when
necessary
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: vries at gcc dot gnu.org
Target Milestone: ---
I had the following idea:
The prevent_branch_around_nothing workaround was added to force
a uniform warp after this:
...
{
.reg.u32 %x;
mov.u32 %x, %tid.x;
setp.ne.u32 %r23, %x, 0;
}
@%r23 bra $L2;
$L2:
...
With TARGET_PTX_6_0, we enforce a uniform warp by using bar.warp.sync, and
consequently this workaround is not necessary anymore.
...
However, this introduces the following regression:
...
FAIL: libgomp.fortran/task-detach-8.f90 -Os execution test
FAIL: libgomp.oacc-c/../libgomp.oacc-c-c++-common/reduction-7.c
-DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0 -foffload=nvptx-none -O0
-DGOMP_NVPTX_JIT=-O0 execution test
...
Needs investigation. Either the idea is wrong, or the tests FAIL for some
other reason.
