Commit graph

1356 commits

Author SHA1 Message Date
Plamena Manolova
c5f3013cba nir: Don't lower the local work group size if it's variable.
If the local work group size is variable it won't be available
at compile time so we can't lower it in nir_lower_system_values().

Signed-off-by: Plamena Manolova <plamena.n.manolova@gmail.com>

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
2018-11-13 10:57:04 +02:00
Timothy Arceri
34dffcf913 nir: add support for removing redundant stores to copy prop var
For example the following type of thing is seen in TCS from
a number of Vulkan and DXVK games:

	vec1 32 ssa_557 = deref_var &oPatch (shader_out float)
	vec1 32 ssa_558 = intrinsic load_deref (ssa_557) ()
	vec1 32 ssa_559 = deref_var &oPatch@42 (shader_out float)
	vec1 32 ssa_560 = intrinsic load_deref (ssa_559) ()
	vec1 32 ssa_561 = deref_var &oPatch@43 (shader_out float)
	vec1 32 ssa_562 = intrinsic load_deref (ssa_561) ()
	intrinsic store_deref (ssa_557, ssa_558) (1) /* wrmask=x */
	intrinsic store_deref (ssa_559, ssa_560) (1) /* wrmask=x */
	intrinsic store_deref (ssa_561, ssa_562) (1) /* wrmask=x */

No shader-db changes on i965 (SKL).

vkpipeline-db results RADV (VEGA):

Totals from affected shaders:
SGPRS: 7832 -> 7728 (-1.33 %)
VGPRS: 6476 -> 6740 (4.08 %)
Spilled SGPRs: 0 -> 0 (0.00 %)
Spilled VGPRs: 0 -> 0 (0.00 %)
Private memory VGPRs: 0 -> 0 (0.00 %)
Scratch size: 0 -> 0 (0.00 %) dwords per thread
Code Size: 469572 -> 456596 (-2.76 %) bytes
LDS: 0 -> 0 (0.00 %) blocks
Max Waves: 989 -> 960 (-2.93 %)
Wait states: 0 -> 0 (0.00 %)

The Max Waves and VGPRS changes here are misleading. What is
happening is a bunch of TCS outputs are being optimised away as
they are now recognised as unused. This results in more varyings
being compacted via nir_compact_varyings() which can result in
more register pressure when they are not packed in an optimal way.
This is an existing problem independent of this patch. I've run
some benchmarks and haven't noticed any performance regressions
in affected games.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-11-13 15:19:36 +11:00
Christian Gmeiner
c6aaafa3a1 nir: add lowering for ffloor
Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-11-12 21:57:25 +01:00
Lionel Landwerlin
8a15f06d19 nir/lower_tex: Add AYUV lowering support
Byte ordering is :

0: V
1: U
2: Y
3: A

v2: Split refactoring of alpha channel (Lionel)

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com> (v1)
Acked-by: Eric Engestrom <eric.engestrom@intel.com> (v2)
2018-11-12 13:22:54 +00:00
Lionel Landwerlin
0a30c33e83 nir/lower_tex: add alpha channel parameter for yuv lowering
We're about to introduce AYUV support which provides its own alpha
channel. So give alpha as a parameter and set it to 1 on exising
formats.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
2018-11-12 13:22:54 +00:00
Timothy Arceri
a068958692 nir: don't pack varyings ints with floats unless flat
Fixes: 1c9c42d16b ("nir: add varying component packing helpers")

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-11-12 15:38:56 +11:00
Timothy Arceri
d40dd05553 nir: add new linking opt nir_link_constant_varyings()
This pass moves constant outputs to the consuming shader stage
where possible.

Reviewed-by: Eric Anholt <eric@anholt.net>
2018-11-10 11:41:00 +11:00
Iago Toral Quiroga
35baee5dce nir/constant_folding: fix incorrect bit-size check
nir_alu_type_get_type_size takes a type as parameter and we were
passing a bit-size instead, which did what we wanted by accident,
since a bit-size of zero matches nir_type_invalid, which has a
size of 0 too.

Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
2018-11-09 08:22:15 +01:00
Jason Ekstrand
61e15348c4 nir: Add a read_mask helper for ALU instructions
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
2018-11-08 10:09:22 -06:00
Timothy Arceri
769ae9fb7f nir: fix condition propagation when src has a swizzle
We cannot use nir_build_alu() to create the new alu as it has no
way to know how many components of the src we will use. This
results in it guessing the max number of components from one of
its inputs.

Fixes the following CTS tests:

dEQP-VK.spirv_assembly.instruction.graphics.selection_block_order.out_of_order_frag
dEQP-VK.spirv_assembly.instruction.graphics.selection_block_order.out_of_order_geom
dEQP-VK.spirv_assembly.instruction.graphics.selection_block_order.out_of_order_tessc
dEQP-VK.spirv_assembly.instruction.graphics.selection_block_order.out_of_order_vert

Fixes: 2975422ceb ("nir: propagates if condition evaluation down some alu chains")

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-11-03 00:44:01 +11:00
Timothy Arceri
c7bdda8aa5 nir: allow propagation of if evaluation for bcsel
Shader-db results Skylake:

total instructions in shared programs: 13109035 -> 13109024 (<.01%)
instructions in affected programs: 4777 -> 4766 (-0.23%)
helped: 11
HURT: 0

total cycles in shared programs: 332090418 -> 332090443 (<.01%)
cycles in affected programs: 19474 -> 19499 (0.13%)
helped: 6
HURT: 4

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-11-02 15:56:34 +11:00
Timothy Arceri
5b757b4097 nir: fix if condition propagation for alu use
We need to update the cursor before we check if the alu use is
dominated by the if condition. Previously we were checking if
the current location of the alu instruction was dominated by
the if condition which would miss some optimisation opportunities.

Fixes: a3b4cb3458 ("nir/opt_if: Rework condition propagation")

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-11-01 09:22:55 +11:00
Eric Anholt
8265dfaa87 nir: Allow using nir_lower_io_to_scalar_early on VS input vars.
This will be used on V3D to cut down the size of the VS inputs in the VPM
(memory area for sharing data between shader stages).

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
2018-10-30 10:46:52 -07:00
Brian Paul
9007c0ed26 nir: fix yet another MSVC build break
Trivial.
2018-10-29 11:15:12 -06:00
Jason Ekstrand
19064b8c3a nir: Add a pass for gathering transform feedback info
This is different from the GL_ARB_spirv pass because it generates a much
simpler data structure that isn't tied to OpenGL and mtypes.h.

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
2018-10-29 17:09:08 +01:00
Brian Paul
7e64e39f8b nir: Fix array initializer
Empty initializer is not standard C.  This fixes MSVC build.

Trivial.
2018-10-26 12:35:48 -06:00
Jason Ekstrand
5bfce5fcc2 nir/system_values: Use the bit size from the load_deref
This isn't a great solution for bit-sizes but we don't have a
particularly convenient way to get a bit size from the system value enum
and this keeps the lowering pass from changing it.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
2018-10-26 11:45:29 -05:00
Jason Ekstrand
a3b4cb3458 nir/opt_if: Rework condition propagation
Instead of doing our own constant folding, we just emit instructions and
let constant folding happen.  This is substantially simpler and lets us
use the nir_imm_bool helper instead of dealing with the const_value's
ourselves.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
2018-10-26 11:45:29 -05:00
Jason Ekstrand
4cd8a58595 nir/search: Use the nir_imm_* helpers from nir_builder
This requires that we rework the interface a bit to use nir_builder but
that's a nice little modernization anyway.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
2018-10-26 11:45:29 -05:00
Jason Ekstrand
6e32115bd6 nir/builder: Handle 16-bit floats in nir_imm_floatN_t
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
2018-10-26 11:45:29 -05:00
Jason Ekstrand
ff45649bc2 nir/builder: Add a nir_imm_true/false helpers
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
2018-10-26 11:45:29 -05:00
Jason Ekstrand
249e32ab17 nir/constant_folding: Use nir_src_as_bool for discard_if
Missed one while converting to the nir_src_as_* helpers.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
2018-10-26 11:45:29 -05:00
Jason Ekstrand
6de1869e86 nir/constant_folding: Add an unreachable to a switch
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
2018-10-26 11:45:29 -05:00
Jason Ekstrand
28bb6abd1d nir/validate: Print when the validation failed
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
2018-10-26 11:45:29 -05:00
Eric Engestrom
e27902a261 util: use C99 declaration in the for-loop set_foreach() macro
Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
2018-10-25 12:43:18 +01:00
Eric Engestrom
bb84fa146f util: use C99 declaration in the for-loop hash_table_foreach() macro
Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
2018-10-25 12:43:18 +01:00
Jose Fonseca
d9a04196d9 nir: Fix array initializer.
Empty initializer is not standard C.  This fixes MSVC build.

Trivial.
2018-10-24 11:37:09 +01:00
Juan A. Suarez Romero
3112da346b nir: fix nir_copy_propagation test
Use nir_src_comp_as_uint() to read the proper second component, as
nir_src_as_uint() returns the first one.

v2: Use nir_src_comp_as_uint() [Jason]

Fixes: 16870de8a0 ("nir: Use nir_src_is_const and nir_src_as_* in core
                     code")
Signed-off-by: Juan A. Suarez Romero <jasuarez@igalia.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108532
Tested-by: Michel Dänzer <michel.daenzer@amd.com>
Tested-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-10-24 09:13:24 +02:00
Samuel Pitoiset
7c694cbfa4 nir: add linking helper nir_link_xfb_varyings()
The linking opts shouldn't try removing or compacting XFB varyings
in the consumer. To avoid this we copy the always_active_io flag
from the producer.

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
2018-10-24 08:21:29 +11:00
Jason Ekstrand
ecb7775e1c nir/algebraic: Fix a typo in the bit size validation code
The conon_bit_class and canon_var_class variables got switched.

Fixes: 932c650e0b "nir/algebraic: Loosen a restriction on variables"
Reported-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
2018-10-23 12:22:29 -05:00
Jason Ekstrand
bf441d22a7 nir/algebraic: Provide descriptive asserts for bit size checks
This will hopefully make debugging opt_algebraic bit-size compile
failures easier.

Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
2018-10-22 16:00:18 -05:00
Jason Ekstrand
932c650e0b nir/algebraic: Loosen a restriction on variables
Previously, we would fail if a variable had an assigned but unknown bit
size X and we tried to assign it an actual bit size.  However, this is
ok because, at the time we do the search, the variable does have an
actual bit size and it will match X because of the NIR rules.

Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
2018-10-22 16:00:18 -05:00
Jason Ekstrand
ea9e651423 nir/algebraic: A bit of validation refactoring'
We rename some local variables in validate() to be more readable and
plumb the var through to get/set_var_bit_class instead of the var index.

Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
2018-10-22 16:00:18 -05:00
Jason Ekstrand
641f4be8e8 nir/algebraic: Make internal classes str-able
Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
2018-10-22 16:00:18 -05:00
Jason Ekstrand
6068be543b nir/algebraic: Generalize an optimization
There's nothing boolean about (a | ~a) ~> -1

Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
2018-10-22 16:00:18 -05:00
Jason Ekstrand
69618a8678 nir/algebraic: Use bool internally instead of bool32
Reviewed-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
2018-10-22 16:00:18 -05:00
Jason Ekstrand
16870de8a0 nir: Use nir_src_is_const and nir_src_as_* in core code
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
2018-10-22 14:24:15 -05:00
Jason Ekstrand
ce36f412c9 nir/search_helpers: Use nir_src_is_const and friends
This not only makes them safe for more bit sizes but it also fixes a bug
in is_zero_to_one where it would return true for constant NaN.

Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
2018-10-22 14:24:15 -05:00
Jason Ekstrand
7bae7828aa nir/search: Use nir_src_is_const and friends
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
2018-10-22 14:24:15 -05:00
Jason Ekstrand
bca5c2c688 nir: Add some new helpers for working with const sources
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
2018-10-22 14:24:15 -05:00
Dave Airlie
ff281e6204 nir: fix clip cull lowering to not assert if GLSL already lowered.
If GLSL has already done the lowering, we'd rather not crash in this pass.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
2018-10-15 18:53:48 -07:00
Caio Marcelo de Oliveira Filho
b3c6146925 nir: Copy propagation between blocks
Extend the pass to propagate the copies information along the control
flow graph.  It performs two walks, first it collects the vars
that were written inside each node. Then it walks applying the copy
propagation using a list of copies previously available.  At each node
the list is invalidated according to results from the first walk.

This approach is simpler than a full data-flow analysis, but covers
various cases.  If derefs are used for operating on more memory
resources (e.g. SSBOs), the difference from a regular pass is expected
to be more visible -- as the SSA copy propagation pass won't apply to
those.

A full data-flow analysis would handle more scenarios: conditional
breaks in the control flow and merge equivalent effects from multiple
branches (e.g. using a phi node to merge the source for writes to the
same deref).  However, as previous commentary in the code stated, its
complexity 'rapidly get out of hand'.  The current patch is a good
intermediate step towards more complex analysis.

The 'copies' linked list was modified to use util_dynarray to make it
more convenient to clone it (to handle ifs/loops).

Annotated shader-db results for Skylake:

    total instructions in shared programs: 15105796 -> 15105451 (<.01%)
    instructions in affected programs: 152293 -> 151948 (-0.23%)
    helped: 96
    HURT: 17

        All the HURTs and many HELPs are one instruction.  Looking
        at pass by pass outputs, the copy prop kicks in removing a
        bunch of loads correctly, which ends up altering what other
        other optimizations kick.  In those cases the copies would be
        propagated after lowering to SSA.

        In few HELPs we are actually helping doing more than was
        possible previously, e.g. consolidating load_uniforms from
        different blocks.  Most of those are from
        shaders/dolphin/ubershaders/.

    total cycles in shared programs: 566048861 -> 565954876 (-0.02%)
    cycles in affected programs: 151461830 -> 151367845 (-0.06%)
    helped: 2933
    HURT: 2950

        A lot of noise on both sides.

    total loops in shared programs: 4603 -> 4603 (0.00%)
    loops in affected programs: 0 -> 0
    helped: 0
    HURT: 0

    total spills in shared programs: 11085 -> 11073 (-0.11%)
    spills in affected programs: 23 -> 11 (-52.17%)
    helped: 1
    HURT: 0

        The shaders/dolphin/ubershaders/12.shader_test was able to
        pull a couple of loads from inside if statements and reuse
        them.

    total fills in shared programs: 23143 -> 23089 (-0.23%)
    fills in affected programs: 2718 -> 2664 (-1.99%)
    helped: 27
    HURT: 0

        All from shaders/dolphin/ubershaders/.

    LOST:   0
    GAINED: 0

The other generations follow the same overall shape.  The spills and
fills HURTs are all from the same game.

shader-db results for Broadwell.

    total instructions in shared programs: 15402037 -> 15401841 (<.01%)
    instructions in affected programs: 144386 -> 144190 (-0.14%)
    helped: 86
    HURT: 9

    total cycles in shared programs: 600912755 -> 600902486 (<.01%)
    cycles in affected programs: 185662820 -> 185652551 (<.01%)
    helped: 2598
    HURT: 3053

    total loops in shared programs: 4579 -> 4579 (0.00%)
    loops in affected programs: 0 -> 0
    helped: 0
    HURT: 0

    total spills in shared programs: 80929 -> 80924 (<.01%)
    spills in affected programs: 720 -> 715 (-0.69%)
    helped: 1
    HURT: 5

    total fills in shared programs: 93057 -> 93013 (-0.05%)
    fills in affected programs: 3398 -> 3354 (-1.29%)
    helped: 27
    HURT: 5

    LOST:   0
    GAINED: 2

shader-db results for Haswell:

    total instructions in shared programs: 9231975 -> 9230357 (-0.02%)
    instructions in affected programs: 44992 -> 43374 (-3.60%)
    helped: 27
    HURT: 69

    total cycles in shared programs: 87760587 -> 87727502 (-0.04%)
    cycles in affected programs: 7720673 -> 7687588 (-0.43%)
    helped: 1609
    HURT: 1416

    total loops in shared programs: 1830 -> 1830 (0.00%)
    loops in affected programs: 0 -> 0
    helped: 0
    HURT: 0

    total spills in shared programs: 1988 -> 1692 (-14.89%)
    spills in affected programs: 296 -> 0
    helped: 1
    HURT: 0

    total fills in shared programs: 2103 -> 1668 (-20.68%)
    fills in affected programs: 438 -> 3 (-99.32%)
    helped: 4
    HURT: 0

    LOST:   0
    GAINED: 1

v2: Remove the DISABLE prefix from tests we now pass.

v3: Add comments about missing write_mask handling. (Caio)
    Add unreachable when switching on cf_node type. (Jason)
    Properly merge the component information in written map
    instead of replacing. (Jason)
    Explain how removal from written arrays works. (Jason)
    Use mode directly from deref instead of getting the var. (Jason)

v4: Register the local written mode for calls. (Jason)
    Prefer cf_node instead of node. (Jason)
    Clarify that remove inside iteration only works in backward
    iterations. (Jason)

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-10-15 17:29:46 -07:00
Caio Marcelo de Oliveira Filho
dc349f07b5 nir: Take call instruction into account in copy_prop_vars
Calls are not used yet (functions are inlined), but since new code is
already taking them into account, do it here too.  The convention here
and in other places is that no writable memory is assumed to remain
unchanged, as well as global variables.

Also, explicitly state the modes affected (instead of using the
reverse logic) in one of the apply_for_barrier_modes calls.

Suggested by Jason.

v2: Consider local vars used by a call to be conservative, SPIR-V has
    such cases. (Jason)

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-10-15 17:29:46 -07:00
Caio Marcelo de Oliveira Filho
797f01c220 nir: Add tests for copy propagation of derefs
Also tests for removal of redundant loads, that we currently handle as
part of the copy propagation.

Note some tests involve multiple blocks and are currently DISABLED
because they (expectedly) fail.

v2: Add missing DISABLED prefix to "multi block" tests. (Jason)

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-10-15 17:29:46 -07:00
Caio Marcelo de Oliveira Filho
4dfa7adc10 nir: Remove handling of dead writes from copy_prop_vars
These are covered by another pass now.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-10-15 17:29:46 -07:00
Caio Marcelo de Oliveira Filho
cb126cf67a nir: Separate dead write removal into its own pass
Instead of doing this as part of the existing copy_prop_vars pass.

Separation makes easier to expand the scope of both passes to be more
than per-block.  For copy propagation, the information about valid
copies comes from previous instructions; while the dead write removal
depends on information from later instructions ("have any instruction
used this deref before overwrite it?").

Also change the tests to use this pass (instead of copy prop vars).
Note that the disabled tests continue to fail, since the standalone
pass is still per-block.

v2: Remove entries from dynarray instead of marking items as
    deleted.  Use foreach_reverse. (Caio)

    (all from Jason)
    Do not cache nir_deref_path.  Not worthy for this patch.
    Clear unused writes when hitting a call instruction.
    Clean up enumeration of modes for barriers.
    Move metadata calls to the inner function.

v3: For copies, use the vector length to calculate the mask.

    (all from Jason)
    Use nir_component_mask_t when applicable.
    Rename functions for clarity.
    Consider local vars used by a call to be conservative (SPIR-V has
    such cases).
    Comment and assert the assumption that stores and copies are
    always to a deref that ends with a vector or scalar.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-10-15 17:29:46 -07:00
Caio Marcelo de Oliveira Filho
a02fd7000d nir: Add tests for dead write elimination
Note at the moment the pass called is nir_opt_copy_prop_vars, because
dead write elimination is implemented there.

Also added tests that involve identifying dead writes in multiple
blocks (e.g. the overwrite happens in another block).  Those currently
fail as expected, so are marked to be skipped.

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-10-15 17:29:46 -07:00
Caio Marcelo de Oliveira Filho
bbda2a17f7 nir: Add test file for vars related passes
Add basic helpers for doing tests on the vars related optimization
passes.  The main goal is to lower the barrier to create tests during
development and debugging of the passes.  Full coverage is not a
requirement.

v2: Make find_next_intrinsic() skip blocks before 'after'. (Jason)
    Move nir_imm_ivec2() to nir_builder.h. (Jason)

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-10-15 17:29:46 -07:00
Caio Marcelo de Oliveira Filho
c869646b7d nir: Add nir_imm_ivec2 helper
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2018-10-15 17:29:46 -07:00
Eric Anholt
7d77fe1bcc nir: Expose nir_remove_unused_io_vars().
For gallium drivers where you want to do some linking at variant compile
time, you don't have the other producer/consumer shader on hand to modify.
By exposing the inner function, the driver can have the used varyings in
the compiled shader cache key and still do linking.

This is also useful for V3D, where the binning shader wants to only output
position and TF varyings.  We've been removing those after nir_lower_io,
but this will be less driver-specific code and let more of the shader get
DCEed early in NIR.

Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
2018-10-15 17:16:44 -07:00