This lets us memoize range analysis work across instructions. Reduces
runtime of shader-db on Intel by -30.0288% +/- 2.1693% (n=3).
Fixes: 405de7ccb6 ("nir/range-analysis: Rudimentary value range analysis pass")
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Each tests has a comment with the expected before and after NIR. The
tests don't actually check this. The tests only check whether or not
the optimization pass reported progress. I couldn't think of a robust,
future-proof way to check the before and after code.
Reviewed-by: Matt Turner <mattst88@gmail.com>
The difference between imov and fmov has been a constant source of
confusion in NIR for years. No one really knows why we have two or when
to use one vs. the other. The real reason is that they do different
things in the presence of source and destination modifiers. However,
without modifiers (which many back-ends don't have), they are identical.
Now that we've reworked nir_lower_to_source_mods to leave one abs/neg
instruction in place rather than replacing them with imov or fmov
instructions, we don't need two different instructions at all anymore.
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Vasily Khoruzhick <anarsoul@gmail.com>
Acked-by: Rob Clark <robdclark@chromium.org>
This pass attempts to dectect code sequences like
if (x < y) {
z = y - x;
...
}
and replace them with sequences like
t = x - y;
if (t < 0) {
z = -t;
...
}
On architectures where the subtract can generate the flags used by the
if-statement, this saves an instruction. It's also possible that moving
an instruction out of the if-statement will allow
nir_opt_peephole_select to convert the whole thing to a bcsel.
Currently only floating point compares and adds are supported. Adding
support for integer will be a challenge due to integer overflow. There
are a couple possible solutions, but they may not apply to all
architectures.
v2: Fix a typo in the commit message and a couple typos in comments.
Fix possible NULL pointer deref from result of push_block(). Add
missing (-A + B) case. Suggested by Caio.
v3: Fix is_not_const_zero to work correctly with types other than
nir_type_float32. Suggested by Ken.
v4: Add some comments explaining how this works. Suggested by Ken.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
