This value is intended to be used to remove out of bounds array
access when unrolling loops so it should contain the comparison
that contains the the induction variable not the overall
condition of the loop terminator. So here we update the instruction
when dealing with iand/ior loop terminator conditions.
Acked-by: Pavel Ondračka <pavel.ondracka@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28998>
We were wrongly telling `nir_const_value_as_uint()` that `iter` had
`bit_size` bits, but in one case it is explicitly i64. This works on
little endian platforms, but caused the nir_loop_unroll_test.fadd{,_rev}
tests to fail on big endian platforms.
Bug: https://bugs.gentoo.org/921297
Fixes: 268ad47c11 ("nir/loop_analyze: Handle bit sizes correctly in calculate_iterations")
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26964>
compute_invariance_information() wasn't doing anything. The only variables
not skipped in the list are phis (which are never considered invariant)
and ALU instructions which use the phi as one of it's sources.
Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23726>
Testing negative iterations count makes no sense, and can cause issues
when the unsigned type is used.
Testing 0 iterations is already covered with
will_break_on_first_iteration, so it can be skipped too.
Fixes: 6772a17a ("nir: Add a loop analysis pass")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9913
Signed-off-by: Sviatoslav Peleshko <sviatoslav.peleshko@globallogic.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26173>
Replacement in try_eval_const_alu() doesn't work because the replacements
are always scalar. The callers also always give a scalar dest.
This is encountered when compiling a Redout shader under ASan.
Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Acked-by: Timothy Arceri <tarceri@itsqueeze.com>
Fixes: bc170e895f ("nir/loop_analyze: Use try_eval_const_alu and induction variable basis info")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26225>
In the tagged commit, we stopped actually inverting the condition, and
instead relied on the "invert_cond" flag. But we missed a few places
where this flag should've been handled too.
Also, add a few more tests to make sure this won't regress in the future.
Fixes: 99a7a664 ("nir/loop_analyze: Change invert_cond instead of changing the condition")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/10012
Signed-off-by: Sviatoslav Peleshko <sviatoslav.peleshko@globallogic.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26024>
First, we need to give the parent_instr field a unique name to be able to
replace with a helper. We have parent_instr fields for both nir_src and
nir_def, so let's rename nir_src::parent_instr in preparation for rework.
This was done with a combination of sed and manual fix-ups.
Then we use semantic patches plus manual fixups:
@@
expression s;
@@
-s->renamed_parent_instr
+nir_src_parent_instr(s)
@@
expression s;
@@
-s.renamed_parent_instr
+nir_src_parent_instr(&s)
@@
expression s;
@@
-s->parent_if
+nir_src_parent_if(s)
@@
expression s;
@@
-s.renamed_parent_if
+nir_src_parent_if(&s)
@@
expression s;
@@
-s->is_if
+nir_src_is_if(s)
@@
expression s;
@@
-s.is_if
+nir_src_is_if(&s)
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Acked-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24671>
Instead, we replace every use of it with nir_def. Most of this commit
was generated by sed:
sed -i -e 's/dest.ssa/def/g' src/**/*.h src/**/*.c src/**/*.cpp
A few manual fixups were required in lima and the nir_legacy code.
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24674>
Instead, we replace it directly with nir_def. We could replace it with
nir_dest but the next commit gets rid of that so this avoids unnecessary
churn. Most of this commit was generated by sed:
sed -i -e 's/dest.dest.ssa/def/g' src/**/*.h src/**/*.c src/**/*.cpp
There were a few manual fixups required in the nir_legacy.c and
nir_from_ssa.c as nir_legacy_reg and nir_parallel_copy_entry both have a
similar pattern.
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24674>
We could add a nir_def_bit_size() helper but we use ->bit_size about 3x
as often as nir_dest_bit_size() today so that's a major Coccinelle
refactor anyway and this doesn't make it much worse. Most of this
commit was generated byt the following semantic patch:
@@
expression D;
@@
<...
-nir_dest_bit_size(D)
+D.ssa.bit_size
...
Some manual fixup was needed, especially in cpp files where Coccinelle
tends to give up the moment it sees any interesting C++.
Acked-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24674>
Every nir_ssa_def is part of a chain of uses, implemented with doubly linked
lists. That means each requires 2 * 64-bit = 16 bytes per def, which is
memory intensive. Together they require 32 bytes per def. Not cool.
To cut that memory use in half, we can combine the two linked lists into a
single use list that contains both regular instruction uses and if-uses. To do
this, we augment the nir_src with a boolean "is_if", and reimplement the
abstract if-uses operations on top of that list. That boolean should fit into
the padding already in nir_src so should not actually affect memory use, and in
the future we sneak it into the bottom bit of a pointer.
However, this creates a new inefficiency: now iterating over regular uses
separate from if-uses is (nominally) more expensive. It turns out virtually
every caller of nir_foreach_if_use(_safe) also calls nir_foreach_use(_safe)
immediately before, so we rewrite most of the callers to instead call a new
single `nir_foreach_use_including_if(_safe)` which predicates the logic based on
`src->is_if`. This should mitigate the performance difference.
There's a bit of churn, but this is largely a mechanical set of changes.
Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22343>
If loop iterator is incremented with something other than regular
addition, it would be more error prone to calculate the number of
iterations theoretically. What we can do instead, is try to emulate the
loop, and determine the number of iterations empirically.
These operations are covered:
- imul
- fmul
- ishl
- ishr
- ushr
Also add unit tests for loop unrollment.
Improves performance of Aztec Ruins (sixonix
gfxbench5.aztec_ruins_vk_high) by -1.28042% +/- 0.498555% (N=5) on Intel
Arc A770.
v2 (idr): Rebase on 3 years. :( Use nir_phi_instr_add_src in the test
cases.
v3 (idr): Use try_eval_const_alu in to evaluate loop termination
condition in get_iteration_empirical. Also restructure the loop
slightly. This fixed off by one iteration errors in "inverted" loop
tests (e.g., nir_loop_analyze_test.ushr_ieq_known_count_invert_31).
v4 (idr): Use try_eval_const_alu in to evaluate induction variable
update in get_iteration_empirical. This fixes non-commutative update
operations (e.g., shifts) when the induction varible is not the first
source. This fixes the unit test
nir_loop_analyze_test.ishl_rev_ieq_infinite_loop_unknown_count.
v5 (idr): Fix _type parameter for fadd and fadd_rev loop unroll
tests. Hopefully that fixes the failure on s390x. Temporarily disable
fmul. This works-around the revealed problem in
glsl-fs-loop-unroll-mul-fp64, and there were no shader-db or fossil-db
changes.
v6 (idr): Plumb max_unroll_iterations into get_iteration_empirical. I
was going to do this, but I forgot. Suggested by Tim.
v7 (idr): Disable fadd tests on s390x. They fail because S390 is weird.
Almost all of the shaders affected (OpenGL or Vulkan) are from gfxbench
or geekbench. A couple shaders in Deus Ex (OpenGL), Dirt Rally (OpenGL),
Octopath Traveler (Vulkan), and Rise of the Tomb Raider (Vulkan) are
helped.
The lost / gained shaders in OpenGL are an Aztec Ruins shader that goes
from SIMD16 to SIMD8. The spills / fills affected are in a single Aztec
Ruins (Vulkan) compute shader.
shader-db results:
Skylake, Ice Lake, and Tiger Lake had similar results. (Tiger Lake shown)
total loops in shared programs: 5514 -> 5470 (-0.80%)
loops in affected programs: 62 -> 18 (-70.97%)
helped: 37 / HURT: 0
LOST: 2
GAINED: 2
Haswell and Broadwell had similar results. (Broadwell shown)
total loops in shared programs: 5346 -> 5298 (-0.90%)
loops in affected programs: 66 -> 18 (-72.73%)
helped: 39 / HURT: 0
fossil-db results:
Skylake, Ice Lake, and Tiger Lake had similar results. (Tiger Lake shown)
Instructions in all programs: 157374679 -> 157397421 (+0.0%)
Instructions hurt: 28
SENDs in all programs: 7463800 -> 7467639 (+0.1%)
SENDs hurt: 28
Loops in all programs: 38980 -> 38950 (-0.1%)
Loops helped: 28
Cycles in all programs: 7559486451 -> 7557455384 (-0.0%)
Cycles helped: 28
Spills in all programs: 11405 -> 11403 (-0.0%)
Spills helped: 1
Fills in all programs: 19578 -> 19588 (+0.1%)
Fills hurt: 1
Lost: 1
Signed-off-by: Yevhenii Kolesnikov <yevhenii.kolesnikov@globallogic.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3445>
These operations are covered:
- imul
- fmul
- ishl
- ishr
- ushr
The only cases that can be currently affected are those where the
calculated loop-trip count would be zero.
v2 (idr): Split out from original commit. Rebase on lots of other work.
v3 (idr): Move operand size assertion. This code only cares that the
operands have the same size for the iadd and fadd cases. In other
cases, such as shifts, the sizes may not match. Fixes assertion
failures in
tests/spec/arb_gpu_shader_int64/glsl-fs-loop-unroll-ishl-int64.shader_test.
No shader-db or fossil-db changes on any Intel platform.
Signed-off-by: Yevhenii Kolesnikov <yevhenii.kolesnikov@globallogic.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3445>
This dramatically simplifies will_break_on_first_iteration, and, much
more importantly, makes it significantly more flexible. It is now
possible to handle loops with more complex exit condition and other
kinds of increment operations.
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3445>
This ensures that scenarios like
nir_loop_analyze_test.iadd_inot_ilt_rev_known_count_5 don't regress in
the next commit. It also means we don't change float comparisons. These
are probably fine... but it still made me a little uneasy.
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3445>
...with a substitution. This function is largely a copy-and-paste of
try_fold_alu (nir_opt_constant_folding.c), and an argument could be made
that this function belongs in that file.
v2: Some changes were mistakenly squashed in to "nir/loop_analyze: Use
try_eval_const_alu and induction variable basis info" that should have
been here.
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3445>
Hoping that I didn't miss any, this *should* add assertions
to all functions and passes which explicitly handle 'nir_loop'.
Acked-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13962>
No longer used. All of the information that was previously track here is
tracked directly in nir_loop_variable... and, technically speaking, has
been tracked there ever since 0b9639c35d.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21289>
These track the same information in a slightly different way. Since
nir_loop_variable::init_src is visible outside this module, it cannot
be eliminated.
As an intentional side effect, induction variables with constant
initializers will now have their nir_loop_induction_variable::init_src
field point to the load_const source. Previously this pointer would be
NULL.
v2: Update unit tests and commit message. Remove the now unused ind_var
variable in find_trip_count.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21289>
These track the same information in a slightly different way. Since
nir_loop_variable::update_src is visible outside this module, it cannot
be eliminated.
This leads to some nice simplification in find_trip_count. Previously
this code only had access to the ALU instruction that performs the
increment. It had to "search" the parameters to determine which (if any)
was the constant. With this change, this code has access to the
nir_alu_src of the ALU instruction that performs the increment. It no
longer needs to search the parameters for the constant. It's either the
supplied nir_alu_src or nothing.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21289>
As an intentional side effect, induction variables with constant
increments will now have their nir_loop_induction_variable::update_src
field point to the load_const source. Previously this pointer would be
NULL.
v2: Update unit tests and commit message.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21289>
Consider the loop:
float i = 0.0;
while (true) {
if (i != 0.0)
break;
i = i + 1.0;
}
This loop clearly executes exactly one time.
Some trickery is necessary to handle cases where the initial loop value
is very large and the increment is, by comparison, very small. From the
fenu_once test case,
float i = -604462909807314587353088.0;
while (true) {
if (i != -604462909807314587353088.0)
break;
i = i + 36028797018963968.0;
}
This loop should also execute exactly once, but this is much more
challenging to calculate due to precision issues.
Going towards smaller magnitude (i.e., adding a small positive value to
a large negative value) requires a smaller delta to make a difference
than going towards a larger magnitude. For this reason,
-604462909807314587353088.0 + 36028797018963968.0 !=
-604462909807314587353088.0, but -604462909807314587353088.0 +
-36028797018963968.0 == -604462909807314587353088.0. Math class is
tough.
No changes in shader-db or fossil-db.
v2: Fix major bug in checking result of the eval_const_binop(nir_op_feq,
...) discovered while developing fneu_once_easy unit test. Fix a typo in
the comment just above that. Add fneu_once_easy test.
v3: Skip the iteration count adjustment tests for nir_op_fenu and
nir_op_ine. Since the iteration count is either 1 or unknown, all this
function can do is add numerical error. Add fenu_once tests.
v4: Change the initial value in the fneu_once test from large positive
to large negative. Change check in get_iteration from nir_op_fsub to
nir_op_fadd. Both changes from discussion with M Henning. Also add some
more explanation in fneu_once.
v5: Rename test cases.
Fixes: 6772a17acc ("nir: Add a loop analysis pass")
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19732>
I discovered this problem because adding an algebraic transformation to
convert some uge and ult to ieq or ine caused a couple loops to stop
unrolling. Consider the loop:
uint i = 0;
while (true) {
if (i >= 1)
break;
i++;
}
This loop clearly executes exactly one time. Note that uge(x, 1) is
equivalent to ine(x, 0). Changing the condition to 'if (i != 0)' will
also execute exactly one time.
In the added test cases, uge_once correctly get an exact loop trip count
of 1. Without the changes to nir_loop_analyze.c, the ine_once case
detects a maximum loop trip count of zero and does not get an exact loop
trip count.
No changes in shader-db or fossil-db.
v2: Move nir_op_fneu changes to a separate commit.
v3: Rename test cases.
Fixes: 6772a17acc ("nir: Add a loop analysis pass")
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19732>
If we know that a select will be eliminated once the loop is
unrolled than we don't need to count the instruction towards the
cost of the loop.
This change helps 2 loops unroll in an xcom enemy unknown shader
that is loaded full of these redundant selects.
Acked-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18587>
Here we move the calculation of the instruction cost of the loop
after we have processed other information such as finding the
induction variables. This is useful because we can use this further
information to find instructions that will be eliminated if the
loop was to unroll and therefore give them a cost of 0.
Acked-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18587>
Ever since 4246c2869c and 7d85dc4f35 loop unrolling can no
longer depend on inot being eliminated from the loop
terminator condition so we need to be able to handle it.
This change avoids 292 loop unrolling regressions with shader-db
once the following patch is applied.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18006>
Ever since 4246c2869c and 7d85dc4f35 loop unrolling can no
longer depend on inot being eliminated from the loop
terminator condition so we need to be able to handle it.
Here we simply check to see if the inot contains a simple
terminator condition we previously handled. We also update
the previous users of this function to use a newly name
copy of the previous behaviour
nir_is_terminator_condition_with_two_inputs().
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18006>
Some drivers don't support these indirects and therefore require
loop unrolling if a shader uses a loop induction variable to
access a sampler array.
Here we add a new nir shader compiler option that drivers can set,
this will be the equivalent of the EmitNoIndirectSampler setting
used in the GLSL IR unrolling pass.
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16543>
Previously we only cared if this was set for the limiting
terminator. However in the following patch we will make use of this
information on other terminators to decide if we can eliminate them.
Reviewed-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16399>
Instead of fail in trip count calculation, just don't mark such
kind of variable as induction from the beginning.
Don't bother inline uniform to deal with such kind of variable
either.
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Qiang Yu <yuq825@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11950>
