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>
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>
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>
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>
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>
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>
