v2: make variable names snake_case
v2: minor cleanups in emit_udiv()
v2: fix Panfrost build failure
v3: use an enum instead of a boolean flag in nir_lower_idiv()'s signature
v4: remove nir_op_urcp
v5: drop nv50 path
v5: rebase
v6: add back nv50 path
v6: add comment for nir_lower_idiv_path enum
v7: rename _nv50/_llvm to _fast/_precise
v8: fix etnaviv build failure
Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
We would like to eliminate not just entire dead instructions, but also
dead components, which increases scheduler flexibility (since some
vector instructions can become scalar after eliminating dead
components). This also will allow better RA in the future.
Results are meh.
total instructions in shared programs: 3453 -> 3451 (-0.06%)
instructions in affected programs: 60 -> 58 (-3.33%)
helped: 2
HURT: 0
total bundles in shared programs: 1826 -> 1824 (-0.11%)
bundles in affected programs: 33 -> 31 (-6.06%)
helped: 2
HURT: 0
total quadwords in shared programs: 3144 -> 3144 (0.00%)
quadwords in affected programs: 0 -> 0
helped: 0
HURT: 0
total registers in shared programs: 321 -> 321 (0.00%)
registers in affected programs: 45 -> 45 (0.00%)
helped: 11
HURT: 11
helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1
helped stats (rel) min: 16.67% max: 50.00% x̄: 39.70% x̃: 50.00%
HURT stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1
HURT stats (rel) min: 100.00% max: 100.00% x̄: 100.00% x̃: 100.00%
95% mean confidence interval for registers value: -0.45 0.45
95% mean confidence interval for registers %-change: -1.87% 62.18%
Inconclusive result (value mean confidence interval includes 0).
total threads in shared programs: 445 -> 447 (0.45%)
threads in affected programs: 2 -> 4 (100.00%)
helped: 1
HURT: 0
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
This allows for vec16 dependencies in the scheduler, not that we have
any yet (thankfully).
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Now that we have notion of byte masks, liveness tracking can be updated
to reflect this extra granularity without loss of correctness.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Read component masks don't have a particular type associated, since the
type of the ALU operation may not match the type of the operands in
question. So let's generate byte masks instead, and update the rest of
the compiler to use byte masks when analyzing reads.
Preparation for mixed types.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
There are essentially two formats of masks in play beginning with this
commit: masks per-channel and masks per-byte. The former make sense
within a given fixed-size instruction; the latter are
typesize-independent. It turns out you need the latter to meaningfully
manipulate instructions containing multiple sizes (which is quite
possible with ALU operations).
Similarly, we have mir_srcsize. We calculate the size of the source by
analyzing the size of the instruction itself and stepping down if there
is a half-modifier.
Finally, we have mir_round_bytemask_down, for when we want to take a
byte mask and "round it down" to a given component size, so that we can
use it as a component mask.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
This will allow us to encode properties about the load/store ops like we
do for ALU ops. We include now properties about whether we have a store,
and if there are special cases on the load/store op. We also tag each
instruction by its natural size... this is probably not totally right,
but it's a start.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
The trick is realizing even with a destination override, the masks are encoded in the same mode as the
instruction itself, rather than stepping down. The override means that
the smaller type is used, but the mask is parsed as if it were the
higher type. Overriding down is down by printed by blinding doing this. Overriding up can be thought of as printing in the upper size, but shifting the alphabet to use the upper half, i.e. shifting xyzw to become abcd.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Add some comments explaining what's going on in a more natural flow in
order to solve the actual bug.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Fixes: 2d914ebe81 ("pan/midgard: Fix memory corruption in register spilling")
It doesn't make sense. You already spilled it once, and it didn't help.
Don't try again, or you'll end up in a loop.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Essentially an off-by-one error ... bit of an edge case, but seems to
occur in some glamor shaders.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
We don't really need to impose this condition, but we do need to cope
with the slightly more general case.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Now that we have live_out calculated per block as metadata, calculating
liveness of an instruction at a given point in the program becomes O(n)
to the size of the block worst-case, rather than O(n) the program.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Callers should have liveness info ready. Ideally we'd have a nice
metadata tracking framework like NIR to handle this automatically, but
for now this will allow us to make forward progress... when we're about
to do something with liveness, invalidate everything ahead to force a
clean calculation.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
This will allow us to explicitly invalidate liveness analysis results so
we can cache liveness results.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
By definition, once liveness analysis has occurred:
live_out = OR {succ} succ->live_in
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
There are unfortunately two distinct liveness analysis passes in the
compiler right now -- one good (but complex) pass used by RA based on
solving data flow equations, and one awful (but simple) pass used for
dead code elimination and bundling based on an abstract walk of the AST.
Let's move RA's pass into shared code so we can work on unifying.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
This allows us to fill in ctx->temp_count explicitly, even if we haven't
squished down the MIR.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
We already enforce this with the SSA/register distinction in the
backend. There is no need to duplicate this logic merely for an assert.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Now that we have constant adjustment logic abstracted, we can do this
safely. Along with the csel inversion patch, this allows many more
common csel ops to inline their condition in the bundle.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
If we can reuse constant slots from other instructions, we would like to
do so to include more instructions per bundle.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
If an instruction could be scheduled to vmul to satisfy the writeout
conditions, let's do that and save an instruction+cycle per fragment
shader.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
We still emit in-order but we switch to using the bundles created from
the new scheduler, which will allow greater flexibility and room for
out-of-order optimization.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
We require chosen instructions to be "close", to avoid ballooning
register pressure. This is a kludge that will go away once we have
proper liveness tracking in the scheduler, but for now it prevents a lot
of needless spilling.
v2: Lower threshold to 6 (from 8). Schedule is hurt, but a few shaders
that spilled excessively are fixed.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Derp
We can bundle two load/store together. This eliminates the need for
explicit load/store pairing in a prepass, as well.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Conditions for branches don't have a swizzle explicitly in the emitted
binary, but they do implicitly get swizzled in whatever instruction
wrote r31, so we need to handle that.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Conditional instructions (csel and conditional branches) require their
condition to be written to a special condition pipeline register (r31.w
for scalar, r31.xyzw for vector). However, pipeline registers are live
only for the duration of a single bundle. As such, the logic to schedule
conditionals correct is surprisingly complex. Essentially, we see if we
could stuff the conditional within the same bundle as the csel/branch
without breaking anything; if we can, we do that. If we can't, we add a
dummy move to make room.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
A bit of a kludge but allows setting an implicit dependency of synthetic
conditional moves on the actual condition, fixing code generated like:
vmul.feq r0, ..
sadd.imov r31, .., r0
vadd.fcsel [...]
The imov runs simultaneous with feq so it gets garbage results, but it's
too late to add an actual dependency practically speaking, since the new
synthetic imov doesn't have a node associated.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
In the future, we will want to keep track of which components of
constants of various sizes correspond to which parts of the bundle
constants, like in the old scheduler. For now, let's just stub it out
for a simple rule of one instruction with embedded constants per bundle.
We can eventually do better, of course.
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
