There are two problems.
1. This is not NaN safe. 'add.le.sat dst F, Inf F, -Inf F' has a
different result than 'add dst F, Inf F, -Inf F; cmp.le null, dst F, 0F'.
2. Ignoring the first problem, this only produces the desired flags
for LE and G. All other cases can produce the wrong result.
For example, batman_arkham_city_goty.foz 6a63c4caacaa0dae has the
following code:
mad.ge.f0.0(8) g51<1>F g50<8,8,1>F g46<8,8,1>F g11<1,1,1>F
mov.sat(8) g52<1>F g51<1,1,0>F
...
(+f0.0) sel(8) g54<1>UD g53<8,8,1>UD 0x3f000000UD
Without this commit, the saturate is incorrectly propagated to the MAD.
A similar case exists in witcher_3_dxvk_g2.foz 5b03243be667a275.
There are even worse cases like total_war_warhammer3.dx12vk-g6.foz
78328466761ef7ab and ee920491573860fc. The former has the following
code (and the latter has very similar code):
mad.l.f0.0(16) g95<1>F g93<8,8,1>F g62<8,8,1>F g68<1,1,1>F
...
mov.sat(16) g109<1>F -g95<1,1,0>F
...
(+f0.0) sel(16) g68<1>UD g111<1,1,0>UD g54<1,1,0>UD
(+f0.0) sel(16) g70<1>UD g113<1,1,0>UD g56<1,1,0>UD
(+f0.0) sel(16) g72<1>UD g115<1,1,0>UD g58<1,1,0>UD
Saturate propagation makes a hash of this code:
mad.sat.l.f0.0(16) g106<1>F -g93<8,8,1>F -g62<8,8,1>F g68<1,1,1>F
...
(+f0.0) sel(16) g70<1>UD g110<1,1,0>UD g56<1,1,0>UD
(+f0.0) sel(16) g72<1>UD g112<1,1,0>UD g58<1,1,0>UD
(+f0.0) sel(16) g68<1>UD g108<1,1,0>UD g54<1,1,0>UD
Not only is the saturate incorrectly applied to the MAD, but the MAD
result is negated without changing the conditional modifier to G!
NOTE: Backports of this commit to stable branches may need to be more
like the following commit to elk.
shader-db:
All Intel platforms had similar results. (Meteor Lake shown)
total instructions in shared programs: 19729375 -> 19729377 (<.01%)
instructions in affected programs: 112 -> 114 (1.79%)
helped: 0
HURT: 2
total cycles in shared programs: 916234266 -> 916234288 (<.01%)
cycles in affected programs: 636 -> 658 (3.46%)
helped: 0
HURT: 2
fossil-db:
All Intel platforms had similar results. (Meteor Lake shown)
Totals:
Instrs: 151531594 -> 151531601 (+0.00%)
Cycle count: 17209107419 -> 17209107474 (+0.00%); split: -0.00%, +0.00%
Totals from 6 (0.00% of 630198) affected shaders:
Instrs: 4550 -> 4557 (+0.15%)
Cycle count: 194629 -> 194684 (+0.03%); split: -0.00%, +0.03%
Fixes: 947c828d5c ("i965/fs: Add a saturation propagation optimization pass.")
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29774>
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>
Wait and see if we actually have a candidate for saturate propagation
before requesting liveness info. Saves the calculation in the case
where we have nothing to do.
Cuts compile time in Borderlands 3 by -0.304754% +/- 0.194162% (n=25).
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29849>
This involves wrapping fs_live_variables in a BRW_ANALYSIS object and
hooking it up to invalidate_analysis() so it's properly invalidated.
Seems like a lot of churn but it's fairly straightforward. The
fs_visitor invalidate_ and calculate_live_intervals() methods are no
longer necessary after this change.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4012>
This reverts commit 40b3abb4d1.
It is not clear that this commit was entirely correct, and unfortunately
it was pushed by error.
CC: Jason Ekstrand <jason@jlekstrand.net>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>
Otherwise it could propagate the saturation from a SIMD16 instruction
into a SIMD8 instruction. With that, only part of the destination
register, which is the source of the move with saturation, would have
been updated.
Reviewed-by: Matt Turner <mattst88@gmail.com>
This function is used in two different scenarios that for 32-bit
instructions are the same, but for 16-bit instructions are not.
One scenario is that in which we are working at a SIMD8 register
level and we need to know if a register is fully defined or written.
This is useful, for example, in the context of liveness analysis or
register allocation, where we work with units of registers.
The other scenario is that in which we want to know if an instruction
is writing a full scalar component or just some subset of it. This is
useful, for example, in the context of some optimization passes
like copy propagation.
For 32-bit instructions (or larger), a SIMD8 dispatch will always write
at least a full SIMD8 register (32B) if the write is not partial. The
function is_partial_write() checks this to determine if we have a partial
write. However, when we deal with 16-bit instructions, that logic disables
some optimizations that should be safe. For example, a SIMD8 16-bit MOV will
only update half of a SIMD register, but it is still a complete write of the
variable for a SIMD8 dispatch, so we should not prevent copy propagation in
this scenario because we don't write all 32 bytes in the SIMD register
or because the write starts at offset 16B (wehere we pack components Y or
W of 16-bit vectors).
This is a problem for SIMD8 executions (VS, TCS, TES, GS) of 16-bit
instructions, which lose a number of optimizations because of this, most
important of which is copy-propagation.
This patch splits is_partial_write() into is_partial_reg_write(), which
represents the current is_partial_write(), useful for things like
liveness analysis, and is_partial_var_write(), which considers
the dispatch size to check if we are writing a full variable (rather
than a full register) to decide if the write is partial or not, which
is what we really want in many optimization passes.
Then the patch goes on and rewrites all uses of is_partial_write() to use
one or the other version. Specifically, we use is_partial_var_write()
in the following places: copy propagation, cmod propagation, common
subexpression elimination, saturate propagation and sel peephole.
Notice that the semantics of is_partial_var_write() exactly match the
current implementation of is_partial_write() for anything that is
32-bit or larger, so no changes are expected for 32-bit instructions.
Tested against ~5000 tests involving 16-bit instructions in CTS produced
the following changes in instruction counts:
Patched | Master | % |
================================================
SIMD8 | 621,900 | 706,721 | -12.00% |
================================================
SIMD16 | 93,252 | 93,252 | 0.00% |
================================================
As expected, the change only affects SIMD8 dispatches.
Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>
MADs don't take immediate sources, but we allow them in the IR since it
simplifies a lot of things. I neglected to consider that case.
Fixes: 4009a9ead4 ("i965/fs: Allow saturate propagation to propagate
negations into MADs.")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103616
Reported-and-Tested-by: Ruslan Kabatsayev <b7.10110111@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
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_fs_saturate_propagation.cpp (Browse further)
