[Mesa-dev] [PATCH 00/15] nir: Rework boolean (and maybe all?) conversions
Timothy Arceri
tarceri at itsqueeze.com
Tue Nov 27 00:42:48 UTC 2018
On 10/11/18 3:58 am, Jason Ekstrand wrote:
> In case anyone is wondering my opinion based on my experience writing
> both patch series, I think it's decidedly in the version B camp. The
> code changes required to nir_algebraic and nir_search are almost
> identical between the two besides the whole virtual opcode thing and the
> changes to front-end NIR producers are basically the same as well due to
> having to put 32 suffixes on some things. However, the changes to other
> parts of NIR aren't required and I feel they're very dirty and
> special-casey in version A.
For what its worth I like version B better also.
>
> --Jason
>
> On Thu, Nov 8, 2018 at 9:45 PM Jason Ekstrand <jason at jlekstrand.net
> <mailto:jason at jlekstrand.net>> wrote:
>
> Welcome to this choose-your-own-adventure patch series! The first six
> patches are good-to-go regardless of choices made later. However,
> starting
> with patch 7, we have a choice to make.
>
> Version A of this series reworks NIR conversion opcodes to not have
> sizes
> and instead simply accept any source and destination size regardless of
> whether or not they match. This is something that Connor and I talked
> about some time ago when we were first adding bit sizes. With most
> opcodes, if they have any variable-size sources or a variable size
> destination, all variable sized things must match. This series
> changes the
> rules so that, for conversion ops, they have a variable size source and
> destination which DO NOT have to match. The upside to this is that
> we get
> to throw away piles of opcodes. The downside is that it makes a
> number of
> things: validation, nir_search, constant folding, etc. more complicated
> because they now have to deal with a new set of rules.
>
> Version B of the series, reworks boolean conversions to be like the
> current
> conversions and also have bit sizes. Unfortunately, this makes hash of
> opt_algebraic because, thanks to some applications love of re-inventing
> Boolean operations, we have piles of optimizations that contain b2f,
> f2b,
> b2i and i2b. To deal with that problem (and make opt_algebraic
> easier to
> use in general), version B adds virtual unsized conversion opcodes to
> nir_search so that you can make an expression that matches any i2f
> opcode
> regardless of size. From the perspective of opt_algebraic, then,
> the two
> series are nearly identical. The downside of this approach is that the
> nir_search changes are kind-of hacky and we still have piles of
> conversion
> opcodes. The upside, however, is that we don't have the extra mental
> overhead in constant folding, validation, and elsewhere of having this
> opcode special-case.
>
> What is the fate of NIR? That's up to the people to decide!
>
> Cc: Ian Romanick <ian.d.romanick at intel.com
> <mailto:ian.d.romanick at intel.com>>
> Cc: Connor Abbott <cwabbott0 at gmail.com <mailto:cwabbott0 at gmail.com>>
>
> Jason Ekstrand COMMON (6):
> nir/opcodes: Pull in the type helpers from constant_expressions
> nir/opcodes: Rename tbool to tbool32
> nir/algebraic: Improve a couple error messages
> nir/algebraic: Set variable classes to the explicit bit size
> nir/algebraic: Clean up some __str__ cruft
> nir/algebraic: Improve error messages for replace expressions
>
> Jason Ekstrand VERSION A (9):
> nir: Add a concept of an unsized conversion opcode
> nir/builder: Create sized helpers for unsized conversion opcodes
> nir/constant_expressions: Handle unsized conversion ops
> nir/algebraic: Add support for unsized conversion opcodes
> nir: Switch conversions to unsized opcodes
> FIXUP: Fix NIR producers and consumers to use unsized conversions
> FIXUP: nir/opt_algebraic: Drop bit-size suffixes from conversions
> nir/algebraic: Add 32-bit specifiers to a bunch of booleans
> nir: Make boolean conversions unsized like other types
>
> Jason Ekstrand VERSION B (8):
> nir/algebraic: Refactor codegen a bit
> nir/algebraic: Add support for unsized conversion opcodes
> nir/opt_algebraic: Simplify an optimization using the new search ops
> nir/opt_algebraic: Drop bit-size suffixes from conversions
> nir/opt_algebraic: Add 32-bit specifiers to a bunch of booleans
> nir: Make boolean conversions sized just like the others
> FIXUP: nir/opt_algebraic: Add suffixes to some x2b opcodes
> FIXUP: Fix NIR producers and consumers to use unsized conversions
>
> src/amd/common/ac_nir_to_llvm.c | 32 +--
> src/compiler/glsl/glsl_to_nir.cpp | 2 +-
> src/compiler/nir/nir.c | 67 ++++++
> src/compiler/nir/nir.h | 7 +
> src/compiler/nir/nir_algebraic.py | 174 +++++++++++----
> src/compiler/nir/nir_builder.h | 30 ++-
> src/compiler/nir/nir_builder_opcodes_h.py | 16 +-
> src/compiler/nir/nir_constant_expressions.h | 3 +-
> src/compiler/nir/nir_constant_expressions.py | 59 +++---
> src/compiler/nir/nir_loop_analyze.c | 7 +-
> src/compiler/nir/nir_lower_idiv.c | 2 +-
> src/compiler/nir/nir_lower_int64.c | 2 +-
> src/compiler/nir/nir_opcodes.py | 152 +++++++------
> src/compiler/nir/nir_opcodes_c.py | 89 +-------
> src/compiler/nir/nir_opt_algebraic.py | 199 +++++++++---------
> src/compiler/nir/nir_opt_constant_folding.c | 5 +-
> src/compiler/nir/nir_search.c | 19 +-
> src/compiler/nir/nir_validate.c | 4 +
> src/compiler/spirv/spirv_to_nir.c | 3 +-
> src/compiler/spirv/vtn_glsl450.c | 4 +-
> src/gallium/auxiliary/nir/tgsi_to_nir.c | 8 +-
> .../drivers/freedreno/ir3/ir3_compiler_nir.c | 148 ++++++-------
> src/gallium/drivers/vc4/vc4_program.c | 8 +-
> src/intel/compiler/brw_fs_nir.cpp | 78 +++----
> src/intel/compiler/brw_vec4_nir.cpp | 39 ++--
> src/mesa/program/prog_to_nir.c | 4 +-
> 26 files changed, 626 insertions(+), 535 deletions(-)
>
> --
> 2.19.1
>
>
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