Many shaders contain expression trees of the form:
const_1 * (value * const_2)
Reorganizing these to
(const_1 * const_2) * value
will allow constant folding to combine the constants. Sometimes, these
constants are 2 and 0.5, so we can remove a multiply altogether. Other
times, it can create more immediate constants, which can actually hurt.
Finding a good balance here is tricky. While much more could be done,
this simple patch seems to have a lot of positive benefit while having
a low downside.
shader-db results on Broadwell:
total instructions in shared programs: 8963768 -> 8961369 (-0.03%)
instructions in affected programs: 438318 -> 435919 (-0.55%)
helped: 1502
HURT: 245
total cycles in shared programs: 71527354 -> 71421516 (-0.15%)
cycles in affected programs: 11541788 -> 11435950 (-0.92%)
helped: 3445
HURT: 1224
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eduardo Lima Mitev <elima@igalia.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Matt Turner <mattst88@gmail.com>
No longer used as of last commit.
v2: Rebase.
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Acked-by: Jason Ekstrand <jason@jlekstrand.net> (v1)
v2 (Sam):
- Use uint64 instead of float64 for sources and destinations. (Connor)
Signed-off-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
v2 (Sam):
- Use uint64 instead of float64 for sources and destinations. (Connor)
Signed-off-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
v2:
- Squash the printing doubles related patches into one patch (Sam).
v3:
- Print using PRIx64 format: long is 32-bit on some 32-bit platforms but long
long is basically always 64-bit (Jason).
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
v2:
- Make the users to give the right bit_sizes as arguments (Jason).
Signed-off-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
%ld and %lu aren't the right format specifiers for int64_t and uint64_t
on 32-bit (x86) systems. They're %zu on Linux and %Iu on Windows.
Use the standard C99 macros in hopes that they work everywhere.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
In the first pass of implementing exact handling, I made a mistake with
search-and-replace. In particular, we only reallly handled exact/inexact
on the root of the tree. Instead, we need to check every node in the tree
for an exact/inexact match. As an example of this, consider the following
GLSL code
precise float a = b + c;
if (a < 0) {
do_stuff();
}
In that case, only the add will be declared "exact" and an expression that
looks for "b + c < 0" will still match and replace it with "b < -c" which
may yield different results. The solution is to simply bail if any of the
values are exact when matching an inexact expression.
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
It used to be in nir_gather_info.c until I moved it out to nir.h so it
could be re-used with some linking code that never got merged. We'll move
it back out if and when we have real code to share it with.
Oddly, this did not affect the shader where I first noticed the pattern.
That particular shader doesn't get its if-statement converted to a bcsel
because there are two assignments in the else-statement. This led to me
submitting https://bugs.freedesktop.org/show_bug.cgi?id=94747.
shader-db results:
Sandy Bridge
total instructions in shared programs: 8467384 -> 8467069 (-0.00%)
instructions in affected programs: 36594 -> 36279 (-0.86%)
helped: 46
HURT: 0
total cycles in shared programs: 117573448 -> 117568518 (-0.00%)
cycles in affected programs: 339114 -> 334184 (-1.45%)
helped: 46
HURT: 0
Ivy Bridge / Haswell / Broadwell / Skylake:
total instructions in shared programs: 7774258 -> 7773999 (-0.00%)
instructions in affected programs: 30874 -> 30615 (-0.84%)
helped: 46
HURT: 0
total cycles in shared programs: 65739190 -> 65734530 (-0.01%)
cycles in affected programs: 180380 -> 175720 (-2.58%)
helped: 45
HURT: 1
No change on G45 or Ironlake.
I also tried these expressions, but none of them affected any shaders in
shader-db:
(('bcsel', a, 'a@bool', 'b@bool'), ('ior', a, b)),
(('bcsel', a, 'b@bool', False), ('iand', a, b)),
(('bcsel', a, 'b@bool', 'a@bool'), ('iand', a, b)),
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
The SPIR-V spec says geometry shaders are supposed to have one invocation
by default. The execution mode is only required if there are multiple
invocations.
Previously, the pass assumed that the entrypoint would be whatever function
happened to have the name "main". We really shouldn't trust in the
function names.
Reviewed-by: Rob Clark <robdclark@gmail.com>
