tree cf2993592e615f71b1b492fbe63d1e1b74a8a3c4
parent ccfee78f3a0f95e11392fb9f408a4579fcc9130e
author Kyle Roarty <kyleroarty1716@gmail.com> 1620437370 -0500
committer Matt Sinclair <mattdsinclair@gmail.com> 1625707081 +0000

arch-gcn3,gpu-compute: Set gpuDynInst exec_mask before use

vector_register_file uses the exec_mask of a memory instruction in
order to determine if it should mark a register as in-use or not.
Previously, the exec_mask of memory instructions was only set on
execution of that instruction, which occurs after the code in
vector_register_file. This led to the code reading potentially garbage
data, leading to a scenario where a register would be marked used when
it shouldn't be.

This fix sets the exec_mask of memory instructions in schedule_stage,
which works because the only time the wavefront execMask() is updated is
on a instruction executing, and we know the previous instruction will
have executed by the time schedule_stage executes, due to the order the
pipeline is executed in.

This also undoes part of a patch from last year (62ec973) which treated
the symptom of accidental register allocation, without preventing the
registers from being allocated in the first place.

This patch also removes now redundant code that sets the exec_mask in
instructions.cc for memory instructions

Change-Id: Idabd35020000764fb06133ac2458606c1aaf6f04
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45346
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Maintainer: Matthew Poremba <matthew.poremba@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>