The intention of inst->is_partial_write() is that it should return true
when any REG_SIZE (32B) chunk of inst's destination is written but not
fully overwritten. This can be used to tell whether inst combines new
data with existing data, or screens off any previous writes, so the old
values are no longer required.
The existing (exec_size * brw_type_size_bytes(this->dst.type) < 32)
check doesn't work in a number of cases. For example, LSC block loads
have exec_size == 1 and force_writemask_all set, but may write multiple
full registers of data. (Currently, we only see them with exec_size 1
after logical-send-lowering, so our SHADER_OPCODE_SEND special case
was covering those.) We had also special cased UNDEF.
Instead, we can simply check:
1. Predication
2. !inst->dst.contiguous()
3. inst->dst.offset % REG_SIZE != 0
4. inst->size_written % REG_SIZE != 0
We had the first three already, but #4 is new. If either #3 or #4
are true, then that implies there is a REG_SIZE chunk of the destination
which is written, but not entirely written, so it's a partial write.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Reviewed-by: Rohan Garg <rohan.garg@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30828>
The specific pattern from the unit test was observed in ray tracing
trampoline shaders.
v2: Refactor the is_raw_move tests out to a utility function. Suggested
by Ken.
v3: Fix a regression caused by being too picky about source
modifiers. This was introduced somewhere between when I did initial
shader-db runs an v2.
v4: Fix typo in comment. Noticed by Caio.
shader-db:
All Intel platforms had similar results. (Meteor Lake shown)
total instructions in shared programs: 19734086 -> 19733997 (<.01%)
instructions in affected programs: 135388 -> 135299 (-0.07%)
helped: 76 / HURT: 2
total cycles in shared programs: 916290451 -> 916264968 (<.01%)
cycles in affected programs: 41046002 -> 41020519 (-0.06%)
helped: 32 / HURT: 29
fossil-db:
Meteor Lake, DG2, and Skylake had similar results. (Meteor Lake shown)
Totals:
Instrs: 151531355 -> 151513669 (-0.01%); split: -0.01%, +0.00%
Cycle count: 17209372399 -> 17208178205 (-0.01%); split: -0.01%, +0.00%
Max live registers: 32016490 -> 32016493 (+0.00%)
Totals from 17361 (2.75% of 630198) affected shaders:
Instrs: 2642048 -> 2624362 (-0.67%); split: -0.67%, +0.00%
Cycle count: 79803066 -> 78608872 (-1.50%); split: -1.75%, +0.25%
Max live registers: 421668 -> 421671 (+0.00%)
Tiger Lake and Ice Lake had similar results. (Tiger Lake shown)
Totals:
Instrs: 149995644 -> 149977326 (-0.01%); split: -0.01%, +0.00%
Cycle count: 15567293770 -> 15566524840 (-0.00%); split: -0.02%, +0.01%
Spill count: 61241 -> 61238 (-0.00%)
Fill count: 107304 -> 107301 (-0.00%)
Max live registers: 31993109 -> 31993112 (+0.00%)
Totals from 17813 (2.83% of 629912) affected shaders:
Instrs: 3738236 -> 3719918 (-0.49%); split: -0.49%, +0.00%
Cycle count: 4251157049 -> 4250388119 (-0.02%); split: -0.06%, +0.04%
Spill count: 28268 -> 28265 (-0.01%)
Fill count: 50377 -> 50374 (-0.01%)
Max live registers: 470648 -> 470651 (+0.00%)
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30251>
If there are no uniforms to push, don't emit the AND or invalidate the
shader analysis. This affects only compute shaders.
Not a significant impact since lots of shaders end up pushing
uniforms. Fossil-db numbers (restricted to compute pipelines only) for DG2
```
Totals:
Instrs: 3071016 -> 3070894 (-0.00%)
Cycle count: 8320268863 -> 8320264519 (-0.00%)
Totals from 122 (2.70% of 4520) affected shaders:
Instrs: 10675 -> 10553 (-1.14%)
Cycle count: 2060003 -> 2055659 (-0.21%)
```
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30631>
We don't actually need to extend g0's live range to the EOT message
generally - most messages that end a shader are headerless. The main
implicit use of g0 is for constructing scratch headers. With the last
two patches, we now consider scratch access that may exist in the IR
and already extend the liveness appropriately.
There is one remaining problem: spilling. The register allocator will
create new scratch messages when spilling a register, which need to
create scratch headers, which need g0. So, every new spill or fill
might extend the live range of g0, which would create new interference,
altering the graph. This can be problematic.
However, when compiling SIMD16 or SIMD32 fragment shaders, we don't
allow spilling anyway. So, why not use allow g0? Also, when trying
various scheduling modes, we first try allocation without spilling.
If it works, great, if not, we try a (hopefully) less aggressive
schedule, and only allow spilling on the lowest-pressure schedule.
So, even for regular SIMD8 shaders, we can potentially gain the use
of g0 on the first few tries at scheduling+allocation.
Once we try to allocate with spilling, we go back to reserving g0
for the entire program, so that we can construct scratch headers at
any point. We could possibly do better here, but this is simple and
reliable with some benefit.
Thanks to Ian Romanick for suggesting I try this approach.
fossil-db on Alchemist shows some more spill/fill improvements:
Totals:
Instrs: 149062395 -> 149053010 (-0.01%); split: -0.01%, +0.00%
Cycles: 12609496913 -> 12611652181 (+0.02%); split: -0.45%, +0.47%
Spill count: 52891 -> 52471 (-0.79%)
Fill count: 101599 -> 100818 (-0.77%)
Scratch Memory Size: 3292160 -> 3197952 (-2.86%)
Totals from 416541 (66.59% of 625484) affected shaders:
Instrs: 124058587 -> 124049202 (-0.01%); split: -0.01%, +0.01%
Cycles: 3567164271 -> 3569319539 (+0.06%); split: -1.61%, +1.67%
Spill count: 420 -> 0 (-inf%)
Fill count: 781 -> 0 (-inf%)
Scratch Memory Size: 94208 -> 0 (-inf%)
Witcher 3 shows a 33% reduction in scratch memory size, for example.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30319>
Due to recent regression, adding INTEL_DEBUG=optimizer is dumping
shader optimization pass details to console rather than to respective
files.
Thank you, Kenneth W Graunke for helping me figure this out.
Fixes: 17b7e49089 ("intel/brw: Move out of fs_visitor and rename print instructions")
Signed-off-by: Sushma Venkatesh Reddy <sushma.venkatesh.reddy@intel.com>
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30389>
Doxygen documentation says
> If the file name is omitted (i.e. the line after \file is left
> blank) then the documentation block that contains the \file command will
> belong to the file it is located in.
so we can omit the filename itself when using the annotation.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30168>
Gfx 12.5 moved scratch to a surface and SURFTYPE_SCRATCH has this pitch
restriction:
RENDER_SURFACE_STATE::Surface Pitch
For surfaces of type SURFTYPE_SCRATCH, valid range of pitch is:
[63,262143] -> [64B, 256KB]
The pitch of the surface is the scratch size per thread and the surface
should be large enough to accommodate every physical thread.
So here adding a new field to intel_device_info, setting it in
intel_device_info_init_common() so even offline tools can have it set.
And finally adding a check to fail shader compilation if needed
scratch is larger than supported.
This issue can be reproduced in debug builds when running
dEQP-VK.protected_memory.stack.stacksize_1024 on Gfx 12.5 or newer
platforms.
Ref: BSpec 43862 (r52666)
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30271>
This implements an undocumented workaround for a hardware bug that
affects draw calls with a pixel shader that has 0 push constant cycles
when TBIMR is enabled, which has been seen to lead to a hang with
Fallout 3 and Metal Gear Rising Revengeance. This hardware bug has
been reported as HSDES#22020184996 which is still pending a resolution
by the hardware team. However since this workaround found empirically
has been confirmed to fix the issue reliably and it's relatively
harmless it seems worth checking in already even though no final W/A
number is available nor has the W/A json file been updated.
To avoid the issue we simply pad the push constant payload to be at
least 1 register. This is enabled via a brw_wm_prog_key since the
driver needs to be in agreement with the compiler on whether the dummy
push constant cycle is present, and it can be avoided in cases where
the driver knows that TBIMR will be disabled (e.g. for BLORP).
Related: https://gitlab.freedesktop.org/mesa/mesa/-/issues/10728
Related: https://gitlab.freedesktop.org/mesa/mesa/-/issues/11399
Fixes: 57decad976 ("intel/xehp: Enable TBIMR by default.")
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30031>
The ALU-based implementation of the barycentric interpolation
intrinsics introduced by a subsequent commit will require some
primitive setup information not delivered in the PS thread payload
unless explicitly requested:
- "Source Depth and/or W Attribute Vertex Deltas" if a
perspective-correct interpolation mode is used -- Note that this is
already requested for CPS interpolation, we just need to enable it
in more cases.
- "Perspective Bary Planes" if a perspective-correct interpolation
mode is used.
- "Non-Perspective Bary Planes" if a non-perspective-corrected
interpolation mode is used.
- "Sample offsets" if any at_sample interpolation is used so the
coordinate offsets of the sample can be calculated.
This ALU implementation of barycentric interpolation will only be
needed for *_at_offset and *_at_sample interpolation, since the fixed
function hardware still computes barycentrics for us at the current
sample coordinates, only the cases that previously relied on the Pixel
Interpolator shared function need to be re-implemented with ALU
instructions, since that shared function will no longer exist on Xe2
hardware.
Thanks to Rohan for a bugfix of the uses_sample_offsets calculation,
this patch includes his fix squashed in.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29847>
Change so the size rounds up to the next multiple of the horizontal stride like
is done for VGRF. This was causing an inconsistency in regs_read() -- The original
component_size() calculation for FIXED_GRF excluded any padding at the end but it was
still being discounted by regs_read().
Suggested by Curro.
Fixes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/11069
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29736>
Like NIR, we print SSA defs as %1, %2, and so on. The number here is
the VGRF number. VGRFs that don't correspond to a SSA def remain
printed as vgrf1, vgrf2, and so on.
This makes it much easier to see what values are SSA and which aren't.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28666>
This introduces a new analysis pass that opportunistically looks for
VGRFs which happen to satisfy the SSA definition properties.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28666>
Our code to initialize gl_SubgroupInvocation uses multiple instructions
some of which are partial writes. This makes it difficult to analyze
expressions involving gl_SubgroupInvocation, which appear very
frequently in compute shaders.
To make this easier, we add a new virtual opcode which initializes
a full VGRF to the value of gl_SubgroupInvocation. (We also expand
it to UD for SIMD8 so there are not partial write issues.) We then
lower it to the original code later on in compilation, after we've
done the bulk of our optimizations.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28666>
This flag is mostly redundant with uses_discard and was only
introduced to implement demote with LLVM when it didn't have
that intrinsic.
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27617>
These were removed with Icelake. While they technically still exist on
Skylake, which this compiler supports, we have never used these opcodes
in the 14 years we could have done so. So just scrap them.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29665>
Removed mention of Wa_* when referencing an intended harware behavior
since version 12. This will prevent the erroneous usage of the
`intel_needs_workaround` in the future.
Reviewed-by: Mark Janes <markjanes@swizzler.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29559>
In 2c65d90bc8 I forgot to add the new SHADER_OPCODE_READ_MASK_REG
opcode to the list of barrier instruction in the scheduler. Let's just
use a single opcode for all ARF registers that need special
scoreboarding and put the register as source (nicer for the debug
output).
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 2c65d90bc8 ("intel/brw: ensure find_live_channel don't access arch register without sync")
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29446>
Another architecture register that requires some care before reading.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 49ee3ae9e8 ("intel/compiler: Lower FIND_[LAST_]LIVE_CHANNEL in IR on Gfx8+")
Tested-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29319>
Some commas were being skipped, according to history as an attempt
to elide BAD_FILEs, but we still print them, so be consistent. Also
for instructions without any sources, the trailing comma was always
being printed. Fix that too.
Example of instruction output before the change
halt_target(8) (null):UD,
send(8) (mlen: 1) (EOT) (null):UD, 0u, 0u, g126:UD(null):UD NoMask
and after it
halt_target(8) (null):UD
send(8) (mlen: 1) (EOT) (null):UD, 0u, 0u, g126:UD, (null):UD NoMask
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29114>
It was the default to show register pressure for each instruction,
but it gets in the way of cleaner diffs before/after an optimization pass.
Add INTEL_DEBUG=reg-pressure option to show it again.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29114>
The sequential IP cause noise when diffing before/after a pass that
either add or remove instructions.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29114>
With the previous commit, we now have new builder helpers that will
allocate a temporary destination for us. So we can eliminate a lot
of the temporary naming and declarations, and build up expressions.
In a number of cases here, the code was confusingly mixing D-type
addresses with UD-immediates, or expecting a UD destination. But the
underlying values should always be positive anyway. To accomodate the
type inference restriction that the base types much match, we switch
these over to be purely UD calculations. It's cleaner to do so anyway.
Compared to the old code, this may in some cases allocate additional
temporary registers for subexpressions.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28957>
Always select sample barycentric when persample dispatch is unknown at
compile time and let the payload adjustments feed the expected value
based on dispatch.
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: mesa-stable
Reviewed-by: Ivan Briano <ivan.briano@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27803>
