As of a10d4937, we would really like things associated with an instruction
to be allocated out of that instruction and not out of the shader. In
particular, you should be passing the instruction that will ultimately be
holding the source into nir_src_copy rather than an arbitrary memory
context.
We also change the prototypes of nir_dest_copy and nir_alu_src/dest_copy to
explicitly take an instruction so we catch this earlier in the future.
Cc: "11.0" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Thomas Helland <thomashelland90@gmail.com>
We want to start reworking and expanding this code, but it'll be a lot
easier to do once we disentangle it from the rest of the stuff in nir.c.
Unfortunately, there are a few unavoidable dependencies in nir.c on
methods we'd rather not expose publicly, since if not used in very
specific situations they can cause Bad Things (tm) to happen. Namely, we
need to do some magical control flow munging when adding/removing jumps.
In the future, we may disallow adding/removing jumps in
nir_instr_insert_*() and nir_instr_remove(), and use separate functions
that are part of the control flow modification code, but for now we
expose them and put them in a separate, private header.
Signed-off-by: Connor Abbott <connor.w.abbott@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
These are basically just moves, so they should be safe as well.
When disabling i965's GLSL IR level scalarizer (channel expressions)
pass, I started seeing NIR code like this:
if ssa_21 {
block block_1:
/* preds: block_0 */
vec4 ssa_120 = vec4 ssa_82, ssa_83, ssa_84, ssa_30
/* succs: block_3 */
} else {
block block_2:
/* preds: block_0 */
/* succs: block_3 */
}
block block_3:
/* preds: block_1 block_2 */
vec4 ssa_33 = phi block_1: ssa_120, block_2: ssa_2
Previously, the GLSL IR scalarizer pass would break the vec4 into a
series of fmovs, which were allowed by the peephole pass. But with
the vec4 operation, they were not. We want to keep getting selects.
Normal i965 on Broadwell:
instructions in affected programs: 200 -> 176 (-12.00%)
helped: 4
With brw_fs_channel_expressions() disabled:
instructions in affected programs: 1832 -> 1646 (-10.15%)
helped: 30
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
This commit switches us from the current setup of using hash sets for
use/def sets to using linked lists. Doing so should save us quite a bit of
memory because we aren't carrying around 3 hash sets per register and 2 per
SSA value. It should also save us CPU time because adding/removing things
from use/def sets is 4 pointer manipulations instead of a hash lookup.
Running shader-db 50 times with USE_NIR=0, NIR, and NIR + use/def lists:
GLSL IR Only: 586.4 +/- 1.653833
NIR with hash sets: 675.4 +/- 2.502108
NIR + use/def lists: 641.2 +/- 1.557043
I also ran a memory usage experiment with Ken's patch to delete GLSL IR and
keep NIR. This patch cuts an aditional 42.9 MiB of ralloc'd memory over
and above what we gained by deleting the GLSL IR on the same dota trace.
On the code complexity side of things, some things are now much easier and
others are a bit harder. One of the operations we perform constantly in
optimization passes is to replace one source with another. Due to the fact
that an instruction can use the same SSA value multiple times, we had to
iterate through the sources of the instruction and determine if the use we
were replacing was the only one before removing it from the set of uses.
With this patch, uses are per-source not per-instruction so we can just
remove it safely. On the other hand, trying to iterate over all of the
instructions that use a given value is more difficult. Fortunately, the
two places we do that are the ffma peephole where it doesn't matter and GCM
where we already gracefully handle duplicates visits to an instruction.
Another aspect here is that using linked lists in this way can be tricky to
get right. With sets, things were quite forgiving and the worst that
happened if you didn't properly remove a use was that it would get caught
in the validator. With linked lists, it can lead to linked list corruption
which can be harder to track. However, we do just as much validation of
the linked lists as we did of the sets so the validator should still catch
these problems. While working on this series, the vast majority of the
bugs I had to fix were caught by assertions. I don't think the lists are
going to be that much worse than the sets.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Shader-db results on HSW:
total instructions in shared programs: 4174156 -> 4157291 (-0.40%)
instructions in affected programs: 145397 -> 128532 (-11.60%)
helped: 383
HURT: 0
GAINED: 20
LOST: 22
There are two more tests lost than gained. However, comparing this with
GLSL IR vs. NIR results, the overall delta is reduced from 85/44
gained/lost on current master to 71/32 with this commit. Therefore, I
think it's probably a boon since we are getting "closer" to where we were
before.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Previously we tried to do poor-man's copy propagation as we created the
select instructions. Instead, this commit just moves the instructions from
the blocks inside the if into the block before. Copy propagation will take
care of making sure we don't have any extra mov's in there for us.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
This avoids the overhead of copying structures and better matches the newly
added nir_alu_src_copy and nir_alu_dest_copy.
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
There aren't many users yet, but I wanted to do this from my scalarizing
pass.
v2: Constify the src arguments.
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Almost all instructions we nir_ssa_def_init() for are nir_dests, and you
have to keep from forgetting to set is_ssa when you do. Just provide the
simpler helper, instead.
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Designated initializers with anonymous unions don't work in MSVC or
GCC < 4.6. With a couple of constructor methods, we don't need them any
more and the code is actually cleaner.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88467
Reviewed-by: Connor Abbot <cwabbott0@gmail.com>
Previously, the condition was a scalar that applied to all components
simultaneously. As of this commit, the condition is a vector and each
component is switched seperately.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
nir_metadata_dirty was a terrible name because the parameter it takes is
the metadata to be preserved. This is really confusing because it looks
like it's doing the opposite of what it is actually doing. Now it's named
sensibly.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Instead, we give SSA definitions a temporary index of 0xFFFFFFFF if the
instruction does not have a block and a proper index when it actually gets
added to the list.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Jason Ekstrand
Connor Abbott
Kenneth Graunke
Matt Turner
Eric Anholt