In the last phase of the schedule and RA loop, the RA call is redundant
if we spill. Immediately afterwards, we're going to see that we
couldn't allocate without spilling and call back into RA and tell it to
go ahead and spill. We've known about it for a while but we've always
brushed over it on the theory that, if you're going to spill, you'll be
calling RA a bunch anyway and what does one extra RA hurt? As it turns
out, it hurts more than you'd expect. Because the RA interference graph
gets sparser with each spill and the RA algorithm is more efficient on
sparser graphs, the RA call that we're duplicating is actually the most
expensive call in the RA-and-spill loop.
There's another extra RA call we do that's a bit harder to see which
this also removes. If we try to compile a shader that isn't the minimum
dispatch width and it fails to allocate without spilling we call fail()
to set an error but then go ahead and do the first spilling RA pass and
only after that's complete do we detect the fail and bail out. By
making minimum dispatch widths part of the spill condition, we side-step
this problem.
Getting rid of these extra spills takes the compile time of a nasty
Aztec Ruins shader from about 28 seconds to about 26 seconds on my
laptop. It also makes shader-db 1.5% faster
Shader-db results on Kaby Lake:
total instructions in shared programs: 15311100 -> 15311100 (0.00%)
instructions in affected programs: 0 -> 0
helped: 0
HURT: 0
total cycles in shared programs: 355468050 -> 355468050 (0.00%)
cycles in affected programs: 0 -> 0
helped: 0
HURT: 0
Total CPU time (seconds): 2524.31 -> 2486.63 (-1.49%)
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
For the W or UW (signed or unsigned word) source types, the 16-bit value
must be replicated in both the low and high words of the 32-bit
immediate value.
v2: Fix replication in other places as well
V3: fix a few nits (Matt Turner)
Signed-off-by: Sagar Ghuge <sagar.ghuge@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
This reverts commit 40b3abb4d1.
It is not clear that this commit was entirely correct, and unfortunately
it was pushed by error.
CC: Jason Ekstrand <jason@jlekstrand.net>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>
On gen11, instead of using a PLN instruction, we convert
FS_OPCODE_LINTERP to 2 or 4 multiply adds. That is done in the
fs_generator code.
This patch adds a lowering pass that does the same thing at the
fs_visitor. It also drops the usage of NF types, since we don't need the
extra precision and it lets us skip the accumulator. With all that, some
optimizations will still be run on the generated code, and we should get
better scheduling.
v2: Update comment about saturation and conditional mod (Matt)
Reviewed-by: Matt Turner <mattst88@gmail.com>
Move the scalar-region conversion from the IR to the generator, so it
doesn't affect the Gen11 path. We need the non-scalar regioning
for a later lowering pass that we are adding.
v2: Better commit message (Matt)
Reviewed-by: Matt Turner <mattst88@gmail.com>
We add two new texture sources for bindless surface and sampler handles.
Bindless surface handles are expected to be pre-shifted so that the
20-bit surface state table index is in the top 20 bits of the 32-bit
handle. This lets us avoid any extra shifts in the shader. Bindless
sampler handles are 32-byte aligned byte offsets from general state base
address. We use 32-byte aligned instead of 16-byte aligned to avoid
having to use more indirect messages than needed. It means we can't
tightly pack samplers but that's probably not a big deal.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
It is very likely that this optimzation is never useful and we'll probably
just end up removing it, so let's not bother adding more cases to it for
now.
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
NIR already has these and correctly considers exact/inexact qualification,
whereas the backend doesn't and can apply the optimizations where it
shouldn't. This happened to be the case in a handful of Tomb Raider shaders,
where NIR would skip the optimizations because of a precise qualification
but the backend would then (incorrectly) apply them anyway.
Besides this, considering that we are not emitting much math in the backend
these days it is unlikely that these optimizations are useful in general. A
shader-db run confirms that MAD and LRP optimizations, for example, were only
being triggered in cases where NIR would skip them due to precise
requirements, so in the near future we might want to remove more of these,
but for now we just remove the ones that are not completely correct.
Suggested-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
This function is used in two different scenarios that for 32-bit
instructions are the same, but for 16-bit instructions are not.
One scenario is that in which we are working at a SIMD8 register
level and we need to know if a register is fully defined or written.
This is useful, for example, in the context of liveness analysis or
register allocation, where we work with units of registers.
The other scenario is that in which we want to know if an instruction
is writing a full scalar component or just some subset of it. This is
useful, for example, in the context of some optimization passes
like copy propagation.
For 32-bit instructions (or larger), a SIMD8 dispatch will always write
at least a full SIMD8 register (32B) if the write is not partial. The
function is_partial_write() checks this to determine if we have a partial
write. However, when we deal with 16-bit instructions, that logic disables
some optimizations that should be safe. For example, a SIMD8 16-bit MOV will
only update half of a SIMD register, but it is still a complete write of the
variable for a SIMD8 dispatch, so we should not prevent copy propagation in
this scenario because we don't write all 32 bytes in the SIMD register
or because the write starts at offset 16B (wehere we pack components Y or
W of 16-bit vectors).
This is a problem for SIMD8 executions (VS, TCS, TES, GS) of 16-bit
instructions, which lose a number of optimizations because of this, most
important of which is copy-propagation.
This patch splits is_partial_write() into is_partial_reg_write(), which
represents the current is_partial_write(), useful for things like
liveness analysis, and is_partial_var_write(), which considers
the dispatch size to check if we are writing a full variable (rather
than a full register) to decide if the write is partial or not, which
is what we really want in many optimization passes.
Then the patch goes on and rewrites all uses of is_partial_write() to use
one or the other version. Specifically, we use is_partial_var_write()
in the following places: copy propagation, cmod propagation, common
subexpression elimination, saturate propagation and sel peephole.
Notice that the semantics of is_partial_var_write() exactly match the
current implementation of is_partial_write() for anything that is
32-bit or larger, so no changes are expected for 32-bit instructions.
Tested against ~5000 tests involving 16-bit instructions in CTS produced
the following changes in instruction counts:
Patched | Master | % |
================================================
SIMD8 | 621,900 | 706,721 | -12.00% |
================================================
SIMD16 | 93,252 | 93,252 | 0.00% |
================================================
As expected, the change only affects SIMD8 dispatches.
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>
Extended math with half-float operands is only supported since gen9,
but it is limited to SIMD8. In gen8 we lower it to 32-bit.
v2: quashed together the following patches (Jason):
- intel/compiler: allow extended math functions with HF operands
- intel/compiler: lower 16-bit extended math to 32-bit prior to gen9
- intel/compiler: extended Math is limited to SIMD8 on half-float
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>
(allow extended math functions with HF operands,
extended Math is limited to SIMD8 on half-float)
We will never hit a condition where we have src1 and src2 as immediate
operands.
Signed-off-by: Sagar Ghuge <sagar.ghuge@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
libintel_common depends on libintel_compiler, but it contains debug
functionality that is needed by libintel_compiler. Break the circular
dependency by moving gen_debug files to libintel_dev.
Suggested-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This will make that step visible in NIR_PRINT=1.
v2: Also use the macro for the cleanup passes.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
When using quads, instead of mapping the elements to the next 4 local
invocation indices, we map the two next in the "current" row and two
next in the "next row". A side effect is that a thread will execute
the indices in a different order.
We now perform the lowering of both local invocation ID and index
together -- and don't rely anymore on lowering done by
nir_lower_system_values. That is convenient when doing the math for
quads, because we need X and Y to get the right invocation index.
When the pass progresses, fold the constants and clean up to reduce
the noise from the indexing math.
This implements the derivative_group_quadsNV semantics from
NV_compute_shader_derivatives.
v2: Take subgroup_id into account, otherwise only values in the first
subgroup would be used. (Jason)
v3: Calculate invocation index and ID together, to avoid duplicating
some math in the quads case when both index and ID are used. (Jason)
v4: Don't call cleanup passes as part of the lowering, let that to the
call site. (Jason)
Change calculation to use less instructions. (Jason)
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com> (v3)
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Fix the order of src0_alpha and sample mask in fb payload.
From SKL PRM Volume 7, "Data Payload Register Order
for Render Target Write Messages":
Type S0A oM sZ oS M2 M3 M4
SIMD8 1 1 0 0 s0A oM R
SIMD16 1 1 0 0 1/0s0A 3/2s0A oM
It also fixes working of alpha to coverage with sample mask
on GEN6 since now they are in correct order.
Signed-off-by: Danylo Piliaiev <danylo.piliaiev@globallogic.com>
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
From "Alpha Coverage" section of SKL PRM Volume 7:
"If Pixel Shader outputs oMask, AlphaToCoverage is disabled in
hardware, regardless of the state setting for this feature."
From OpenGL spec 4.6, "15.2 Shader Execution":
"The built-in integer array gl_SampleMask can be used to change
the sample coverage for a fragment from within the shader."
From OpenGL spec 4.6, "17.3.1 Alpha To Coverage":
"If SAMPLE_ALPHA_TO_COVERAGE is enabled, a temporary coverage value
is generated where each bit is determined by the alpha value at the
corresponding sample location. The temporary coverage value is then
ANDed with the fragment coverage value to generate a new fragment
coverage value."
Similar wording could be found in Vulkan spec 1.1.100
"25.6. Multisample Coverage"
Thus we need to compute alpha to coverage dithering manually in shader
and replace sample mask store with the bitwise-AND of sample mask and
alpha to coverage dithering.
The following formula is used to compute final sample mask:
m = int(16.0 * clamp(src0_alpha, 0.0, 1.0))
dither_mask = 0x1111 * ((0xfea80 >> (m & ~3)) & 0xf) |
0x0808 * (m & 2) | 0x0100 * (m & 1)
sample_mask = sample_mask & dither_mask
Credits to Francisco Jerez <currojerez@riseup.net> for creating it.
It gives a number of ones proportional to the alpha for 2, 4, 8 or 16
least significant bits of the result.
GEN6 hardware does not have issue with simultaneous usage of sample mask
and alpha to coverage however due to the wrong sending order of oMask
and src0_alpha it is still affected by it.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109743
Signed-off-by: Danylo Piliaiev <danylo.piliaiev@globallogic.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
We were not copying the saturate bit from the original instruction
to the new replacement instruction. This caused major misrendering
in DiRT Rally on iris, where comparisons leading to discards failed
due to the missing saturate, causing lots of extra garbage pixels to
be drawn in text rendering, trees, and so on.
This did not show up on i965 because st/nir performs a more aggressive
version of nir_opt_peephole_select, yielding more b32csel operations.
Fixes: 52c7df1643 i965/fs: Merge CMP and SEL into CSEL on Gen8+
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
The parameter is never used, and it's not part of a common interface
idiom. Remove it.
src/intel/compiler/brw_interpolation_map.c: In function ‘brw_setup_vue_interpolation’:
src/intel/compiler/brw_interpolation_map.c:62:59: warning: unused parameter ‘devinfo’ [-Wunused-parameter]
const struct gen_device_info *devinfo)
^~~~~~~
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
The scalar back-end uses SHADER_OPCODE_SEND for all surface messages so
we no longer need the non-logical opcodes there. Prefix them VEC4 so
it's clear that they're only used by the vec4 back-end.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
The unused typed surface read/write support in the vec4 back-end has
been dropped and the fs back-end now uses SHADER_OPCODE_SEND for all
image and buffer ops. There's no reason to keep these opcodes around
anymore.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Since switching to SHADER_OPCODE_SEND for image operations, we no longer
need the non-logical opcode.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Because the "low" temporary needs to be accessed with word type and
twice the original stride, attempting to preserve the alignment of the
original destination can potentially lead to instructions with illegal
destination stride greater than four. Because the CHV/BXT alignment
restrictions are now being enforced by the regioning lowering pass run
after lower_integer_multiplication(), there is no real need to
preserve the original strides anymore.
Note that this bug can be reproduced on stable branches, but
back-porting would be non-trivial, because the fix relies on the
regioning lowering pass recently introduced.
Tested-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Currently the execution type calculation will return a bogus value in
cases like:
mov_indirect(8) vgrf0:w, vgrf1:w, vgrf2:ud, 32u
Which will be considered to have a 32-bit integer execution type even
though the actual indirect move operation will be carried out with
16-bit precision.
Similarly there's no need to apply the CHV/BXT double-precision region
alignment restrictions to such control sources, since they aren't
directly involved in the double-precision arithmetic operations
emitted by these virtual instructions. Applying the CHV/BXT
restrictions to control sources was expected to be harmless if mildly
inefficient, but unfortunately it exposed problems at codegen level
for virtual instructions (namely the SHUFFLE instruction used for the
Vulkan 1.1 subgroup feature) that weren't prepared to accept control
sources with an arbitrary strided region.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109328
Reported-by: Mark Janes <mark.a.janes@intel.com>
Fixes: efa4e4bc5f "intel/fs: Introduce regioning lowering pass."
Tested-by: Anuj Phogat <anuj.phogat@gmail.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
By just assigning dst.type to src[i].type, we ensure that the offset at
the end of the loop actually offsets it by the right number of
registers. Otherwise, we'll get into a case where we copy with a Q type
and then offset with a D type and things get out of sync.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Surface reads don't need them because they just have the one address
payload. With surface writes, on the other hand, we can put the address
and the data in the different halves and avoid building the payload all
together.
The decrease in register pressure and added freedom in register
allocation resulting from this change reduces spilling enough to improve
the performance of one customer benchmark by about 2x.
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Like all the other sends, it's just mlen * REG_SIZE.
Fixes: 3cbc02e469 "intel: Use TXS for image_size when we have..."
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
There are piles of fields that it doesn't check so using it is a lie.
The only reason why it's not causing problem is because it has exactly
one user which only uses it for MOV instructions (which aren't very
interesting) and only on Sandy Bridge and earlier hardware. Just get
rid of it and inline it in the one place that it's actually used.
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
The original idea was that the backend compiler could eliminate
surfaces, so we would have it mark which ones are actually used,
then shrink the binding table accordingly. Unfortunately, it's a
pretty blunt mechanism - it can only prune things from the end,
not the middle - since we decide the layout before we even start
the backend compiler, and only limit the size. It also basically
gives up if it sees indirect array access.
Besides, we do the vast majority of our surface elimination in NIR
anyway, not the backend - and I don't see that trend changing any
time soon. Vulkan abandoned this plan a long time ago, and I don't
use it in Iris, but it's still been kicking around in i965.
I hacked shader-db to print the binding table size in bytes, and
observed no changes with this patch. So, this code appears to do
nothing useful.
Acked-by: Jason Ekstrand <jason@jlekstrand.net>
The next patch replaces an unsigned bitfield with a plain unsigned,
which triggers gcc to begin warning on signed/unsigned comparisons.
Keeping this patch separate from the actual move allows bisectablity and
generates no additional warnings temporarily.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
These are broken on a future platform, but it turns out we don't need
to fix them, since they're just type-converting moves with strided
source. Kill them.
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
