The new function takes care of changing an instruction opcode and sources,
which will allow later patches to tweak how allocations are done in
those cases. Like the instruction allocation, this also takes a shader
(or a builder, for it to get a shader).
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36730>
NIR is going to use exec_node/list without the C++ code, and may switch to
a different linked list implementation in the future.
GLSL is going to use ir_exec_node/list, which we want to keep private
for GLSL, so that we can change it easily.
Thus, it's better to fork the C++ version of list.h for Intel.
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36425>
Now that the brw_ip_ranges analysis is being used, there's no
need to track start_ip/end_ips in the blocks as they are mutate. And
also no need to call adjust_block_ips at the end of some passes.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34012>
It was used by the pass tests to verify output with TEST_DEBUG=1,
replace it with brw_print_instructions().
The output is slightly different (not printing IP, not reordering the
blocks), we can add those features as we need, but given the usage was
already very reduced, don't bother with that until need arises.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34012>
Since brw_inst now has the block it belongs and the block can
reach the shader, the only necessary information to create a
builder is the brw_inst itself.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33815>
Make the "block after DO" more stable so that adding instructions after
a DO doesn't require repairing the CFG. Use a new SHADER_OPCODE_FLOW
instruction that is a placeholder representing "go to the next block"
and disappears at code generation.
For some context, there are a few facts about how CFG currently works
- Blocks are assumed to not be empty;
- DO is always by itself in a block, i.e. starts and ends a block;
- There are no empty blocks;
- Predicated WHILE and CONTINUE will link to the "block after DO";
- When nesting loops, it is possible that the "block after DO" is
another "DO".
Reasons and further explanations for those are in the brw_cfg.c comments.
What makes this new change useful is that a pass might want to add
instructions between two DO instructions. When that happens, a new
block must be created and any predicated WHILE and CONTINUE must be
repaired.
So, instead of requiring a repair (which has proven to be tricky in
the past), this change adds a block that can be "virtually" empty but
allow instructions to be added without further changes.
One alternative design would be allowing empty blocks, that would be
a deeper change since the blocks are currently assumed to be not empty
in various places. We'll save that for when other changes are made to
the CFG.
The problem described happens in brw_opt_combine_constants, and a
different patch will clean that up.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33536>
The other dump methods in this file also take a file parameter,
defaulting to stderr. Dumping dot files to stdout is probably not
what anybody really wanted.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30530>
Doxygen documentation says
> If the file name is omitted (i.e. the line after \file is left
> blank) then the documentation block that contains the \file command will
> belong to the file it is located in.
so we can omit the filename itself when using the annotation.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30168>
The base class was used when we had vec4, but now we can fold it with
its only subclass. Declare fs_visitor now as a struct to be able to
forward declare for C code without causing errors due to class/struct
being mixed.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27861>
Add optional argument for both cfg and block dump() function to pass
a FILE*. Default behavior remains dumping to stderr.
v2 (idr): Don't add the new test framework in this commit.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25216>
Imagine 3 blocks A, B, and C. A has a physical link to B, and B has a
logical link to C. Previous to this commit, if B were removed, A would
get a logical link to C. This is not correct.
This was specifically observed to occur when block A was a DO block and
B was the WHILE block. The DO block would have two logical successors,
and that is completely invalid.
v2: Assert that the links from A-to-B and B-back-to-A are the same
kind. Suggested by Caio.
v3: Assume the successor and predecessor lists are well formed. Use this
to simplify the logic. Suggested by Caio. Add checks to cfg_t::validate
to ensure the lists are well formed.
v4: Remove (now unused) bblock_link_invalid. Suggested by Curro.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25216>
The previous is_successor_of and is_predecessor_of checks prevented
creating a physical link when a logical link already existed. However, a
logical link could be added when a physical link already existed. This
change causes an existing physical link to be "promoted" to a logical
link.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25216>
Previously when earlier_block->children.make_empty() was called, the
child blocks would still have links back to earlier_block.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25216>
v2: Use _mesa_shader_stage_to_abbrev(stage) instead of
stage_abbrev. Noticed by Caio and GCC. That's what I get for not
recompiling after rebasing. Wrap cfg_t::validate in NDEBUG
magic. Suggested by Caio.
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25216>
This adds a missing CFG edge that represents a possible physical
control flow path the EU might take under some conditions which isn't
part of the logical CFG of the program. This possibility shouldn't
have led to problems on platforms prior to Gfx12, since the missing
control flow edge cannot possibly influence liveness intervals.
However on Gfx12+ it becomes the compiler's responsibility to resolve
data dependencies across instructions, and the missing physical
control flow paths may lead to a WaR data hazard currently not visible
to the software scoreboard pass, which could lead to data corruption.
Worse, the possibility for this path to be taken by the EU increases
on Gfx12+ due to a hardware bug affecting EU fusion -- However the
same physical path can be potentially taken on earlier platforms as
well, so this patch extends the CFG on all platforms for consistency,
even though the lack of this edge shouldn't lead to any functional
issues on platforms earlier than Gfx12. There are no shader-db
changes on earlier platforms, so there seems to be no disadvantage
from using the same CFG representation as on later platforms.
This issue has ben reported on TGL with the following conformance
test, thanks to Ian for bringing the FULSIM dependency check warning
to my attention:
dEQP-VK.graphicsfuzz.spv-stable-pillars-volatile-nontemporal-store
Fixes: 4d1959e693 ("intel/cfg: Represent divergent control flow paths caused by non-uniform loop execution.")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/4940
Reported-by: Tapani Pälli <tapani.palli@intel.com>
Reported-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14248>
The cycle count estimation logic part of the scheduler is now
redundant with the shader performance modeling pass, and the estimates
can be consolidated into the brw::performance analysis result object
instead of being part of the CFG, which guarantees that the estimates
cannot be accessed without previously calling the
performance_analysis::require() method, which makes sure that the
right analysis pass is executed at the right time if we don't already
have up-to-date cached results.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
It makes sense to keep the result of analysis passes independent from
the IR itself. Instead of representing the idom tree as a pointer in
each basic block pointing to its immediate dominator, the whole
dominator tree is represented separately from the IR as an array of
pointers inside the idom_tree object. This has the advantage that
it's no longer possible to use stale dominance results by accident
without having called require() beforehand, which makes sure that the
idom tree is recalculated if necessary.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>
This only does half of the work. The actual representation of the
idom tree is left untouched, but the computation algorithm is moved
into a separate analysis result class wrapped in a BRW_ANALYSIS
object, along with the intersect() and dump_domtree() auxiliary
functions in order to keep things tidy.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>
This reflects the natural dependency relationship between brw_cfg.h
and brw_shader.h. brw_cfg.h only requires the base IR definitions
which are now part of a separate header.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>
This edge doesn't exist in the original scalar program, but it
represents a potential control flow path the EU will take in cases
where control flow isn't uniform across channels of the same SIMD
thread.
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
This edge doesn't exist in the original scalar program, but it
represents a potential control flow path the EU will take in cases
where the condition isn't uniform across channels of the same SIMD
thread.
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Currently only the physical back-edge is represented, which
incidentally also leads to the exit block of the loop, but we need the
direct logical edge in addition for our logical CFG representation to
be complete.
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
This represents two control flow graphs in the same cfg_t data
structure: The physical CFG that will include all possible control
flow paths the EU can physically take, and the logical CFG restricted
to the control flow paths that exist in the original scalar program.
The latter is a subset of the former because in case of divergence the
SIMD vectorized program will take control flow paths that aren't part
of the original scalar program.
The bblock_link constructor and bblock_t::add_successor() now take a
"kind" parameter that specifies whether the edge is purely physical or
whether it's part of both the logical and physical CFGs (a logical
edge is of course always guaranteed to be in the physical CFG as
well). bblock_t::is_predecessor_of() and ::is_successor_of() also
take a kind parameter specifying which CFG is being queried. The '~>'
notation will be used now in order to represent purely physical edges
in IR dumps.
This commit doesn't actually add nor remove any edges from the CFG
(the only edges marked as purely physical here are the two WHILE loop
ones that already existed). Optimization passes should continue using
the same (incomplete) physical CFG they were using before until
they're fixed to do something smarter in a later commit, so this
shouldn't lead to any functional changes.
v2: Remove tabs from lines changed in this file (Caio).
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Specifically the optimization of a conditional BREAK + WHILE sequence
into a conditional WHILE seems pretty broken. The list of successors
of "earlier_block" (where the conditional BREAK was found) is emptied
and then re-created with the same edges for no apparent reason. On
top of that the list of predecessors of the block immediately after
the WHILE loop is emptied, but only one of the original edges will be
added back, which means that potentially several blocks that still
have it on their list of successors won't be on its list of
predecessors anymore, causing all sorts of hilarity due to the
inconsistency in the control flow graph.
The solution is to remove the code that's removing valid edges from
the CFG. cfg_t::remove_block() will already clean up after itself.
The assert in bblock_t::combine_with() also needs to be removed since
we will be merging a block with multiple children into the first one
of them.
Found the issue on a hardware enabling branch originally, but
apparently somebody reproduced the same problem independently on
master in the meantime.
Fixes: d13bcdb3a9 ("i965/fs: Extend predicated break pass to predicate WHILE.")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111009
Cc: jiradet.jd@gmail.com
Cc: Sergii Romantsov <sergii.romantsov@globallogic.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: mesa-stable@lists.freedesktop.org
Tested-by: Paul Chelombitko <qamonstergl@gmail.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
This addresses a long-standing back-end compiler bug that could lead
to cross-channel data corruption in loops executed non-uniformly. In
some cases live variables extending through a loop divergence point
(e.g. a non-uniform break) into a convergence point (e.g. the end of
the loop) wouldn't be considered live along all physical control flow
paths the SIMD thread could possibly have taken in between due to some
channels remaining in the loop for additional iterations.
This patch fixes the problem by extending the CFG with physical edges
that don't exist in the idealized non-vectorized program, but
represent valid control flow paths the SIMD EU may take due to the
divergence of logical threads. This makes sense because the i965 IR
is explicitly SIMD, and it's not uncommon for instructions to have an
influence on neighboring channels (e.g. a force_writemask_all header
setup), so the behavior of the SIMD thread as a whole needs to be
considered.
No changes in shader-db.
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Mostly a dummy git mv with a couple of noticable parts:
- With the earlier header cleanups, nothing in src/intel depends
files from src/mesa/drivers/dri/i965/
- Both Autoconf and Android builds are addressed. Thanks to Mauro and
Tapani for the fixups in the latter
- brw_util.[ch] is not really compiler specific, so it's moved to i965.
v2:
- move brw_eu_defines.h instead of brw_defines.h
- remove no-longer applicable includes
- add missing vulkan/ prefix in the Android build (thanks Tapani)
v3:
- don't list brw_defines.h in src/intel/Makefile.sources (Jason)
- rebase on top of the oa patches
[Emil Velikov: commit message, various small fixes througout]
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
2017-03-13 11:16:34 +00:00
Renamed from src/mesa/drivers/dri/i965/brw_cfg.cpp (Browse further)
