exec_target¶
How one parallel loop is lowered.
Declaración¶
Sintaxis¶
exec_target = ExecAuto | ExecSerial | ExecHostThreads | ExecDevice
Values¶
Value |
Meaning |
|---|---|
|
not decided yet. This is what the frontend and the passes that build a loop write. |
|
one thread runs the iterations in order, as an ordinary DoLoop. |
|
the iterations are spread over the threads of the host. |
|
the iterations become a GPU kernel, launched with a GpuKernelLaunch. |
Valores devueltos¶
None. An enumeration value is not evaluated.
Descripción¶
The execution target is a member of
OMPRegion, so the choice is made per loop
rather than per compilation. A do concurrent loop, an !$omp target region
and an !$omp parallel do are canonicalized into that one node before
anything lowers them, and each region carries the answer to «who runs these
iterations».
The frontend never picks a target: it writes ExecAuto and leaves the
decision to the parallel_dispatch pass, which reads the command line. Every
lowering below that pass claims only the loops assigned to it, so a loop the
GPU declines can be handed back to the host threads instead of being lost.