diff options
| author | Jason Ekstrand <[email protected]> | 2016-12-19 21:29:51 -0800 |
|---|---|---|
| committer | Jason Ekstrand <[email protected]> | 2016-12-22 16:27:19 -0800 |
| commit | d55835b8bdf031ef3c254a9b7ec1776ad348582b (patch) | |
| tree | 9a9c37683a2f87d7dfa3e3fe03dec931670c29b3 | |
| parent | 8962cc96ec2bc1eb561a438512adc5042e2c8d34 (diff) | |
nir/algebraic: Add optimizations for "a == a && a CMP b"
This sequence shows up The Talos Principal, at least under Vulkan,
and prevents loop analysis from properly computing trip counts in a
few loops.
Reviewed-by: Ian Romanick <[email protected]>
| -rw-r--r-- | src/compiler/nir/nir_opt_algebraic.py | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py index 698ac673658..ff10d701f5e 100644 --- a/src/compiler/nir/nir_opt_algebraic.py +++ b/src/compiler/nir/nir_opt_algebraic.py @@ -464,6 +464,14 @@ def bitfield_reverse(u): optimizations += [(bitfield_reverse('x@32'), ('bitfield_reverse', 'x'))] +# For any float comparison operation, "cmp", if you have "a == a && a cmp b" +# then the "a == a" is redundant because it's equivalent to "a is not NaN" +# and, if a is a NaN then the second comparison will fail anyway. +for op in ['flt', 'fge', 'feq']: + optimizations += [ + (('iand', ('feq', a, a), (op, a, b)), (op, a, b)), + (('iand', ('feq', a, a), (op, b, a)), (op, b, a)), + ] # Add optimizations to handle the case where the result of a ternary is # compared to a constant. This way we can take things like |