From: Timothy Arceri <timothy.arc...@collabora.com>
Didn't turn out as useful as I'd hoped, but it will help alot more on
i965 by reducing regressions when we drop brw_do_channel_expressions()
and brw_do_vector_splitting().
I'm not sure how much sense 'is_not_used_by_conditional' makes on
platforms other than i965 but since this is a new opt it at least
won't do any harm.
shader-db BDW:
total instructions in shared programs: 13029581 -> 13029415 (-0.00%)
instructions in affected programs: 15268 -> 15102 (-1.09%)
helped: 86
HURT: 0
total cycles in shared programs: 247038346 -> 247036198 (-0.00%)
cycles in affected programs: 692634 -> 690486 (-0.31%)
helped: 183
HURT: 27
---
src/compiler/nir/nir_opt_algebraic.py | 4 ++++
src/compiler/nir/nir_search_helpers.h | 15 +++++++++++++++
2 files changed, 19 insertions(+)
diff --git a/src/compiler/nir/nir_opt_algebraic.py
b/src/compiler/nir/nir_opt_algebraic.py
index 49c1460..bd65eff 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -151,20 +151,24 @@ optimizations = [
(('fge', 0.0, ('b2f', a)), ('inot', a)),
(('fge', ('fneg', ('b2f', a)), 0.0), ('inot', a)),
# 0.0 < fabs(a)
# fabs(a) > 0.0
# fabs(a) != 0.0 because fabs(a) must be >= 0
# a != 0.0
(('flt', 0.0, ('fabs', a)), ('fne', a, 0.0)),
+ # ignore this opt when the result is used by a bcsel or if so we can make
+ # use of conditional modifiers on supported hardware.
+ (('flt(is_not_used_by_conditional)', ('fadd(is_used_once)', a, ('fneg',
b)), 0.0), ('flt', a, b)),
+
(('fge', ('fneg', ('fabs', a)), 0.0), ('feq', a, 0.0)),
(('bcsel', ('flt', b, a), b, a), ('fmin', a, b)),
(('bcsel', ('flt', a, b), b, a), ('fmax', a, b)),
(('bcsel', ('inot', a), b, c), ('bcsel', a, c, b)),
(('bcsel', a, ('bcsel', a, b, c), d), ('bcsel', a, b, d)),
(('bcsel', a, True, 'b@bool'), ('ior', a, b)),
(('fmin', a, a), a),
(('fmax', a, a), a),
(('imin', a, a), a),
(('imax', a, a), a),
diff --git a/src/compiler/nir/nir_search_helpers.h
b/src/compiler/nir/nir_search_helpers.h
index faa3bdf..7decf65 100644
--- a/src/compiler/nir/nir_search_helpers.h
+++ b/src/compiler/nir/nir_search_helpers.h
@@ -151,11 +151,26 @@ is_used_once(nir_alu_instr *instr)
return true;
}
static inline bool
is_not_used_by_if(nir_alu_instr *instr)
{
return list_empty(&instr->dest.dest.ssa.if_uses);
}
+static inline bool
+is_not_used_by_conditional(nir_alu_instr *instr)
+{
+ if (!is_not_used_by_if(instr))
+ return false;
+
+ nir_foreach_use(use, &instr->dest.dest.ssa) {
+ if (use->parent_instr->type == nir_instr_type_alu &&
+ nir_instr_as_alu(use->parent_instr)->op == nir_op_bcsel)
+ return false;
+ }
+
+ return true;
+}
+
#endif /* _NIR_SEARCH_ */
--
2.9.3
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