This shuffles constants down in the reverse of what the previous
patch does and applies some simpilifications that may be made
possible from doing so.
Shader-db results BDW:
total instructions in shared programs: 12978405 -> 12975412 (-0.02%)
instructions in affected programs: 279862 -> 276869 (-1.07%)
helped: 1230
HURT: 125
total cycles in shared programs: 246622124 -> 246625712 (0.00%)
cycles in affected programs: 11311912 -> 11315500 (0.03%)
helped: 1666
HURT: 1342
---
src/compiler/nir/nir.h | 1 +
src/compiler/nir/nir_opt_algebraic.py | 23 +++++++++++++++++++++++
src/mesa/drivers/dri/i965/brw_nir.c | 6 ++++++
3 files changed, 30 insertions(+)
diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 8bbc41d..8d6f7d1 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -2569,6 +2569,7 @@ bool nir_lower_phis_to_regs_block(nir_block *block);
bool nir_lower_ssa_defs_to_regs_block(nir_block *block);
bool nir_opt_algebraic(nir_shader *shader);
+bool nir_opt_algebraic_before_ffma(nir_shader *shader);
bool nir_opt_algebraic_late(nir_shader *shader);
bool nir_opt_constant_folding(nir_shader *shader);
diff --git a/src/compiler/nir/nir_opt_algebraic.py
b/src/compiler/nir/nir_opt_algebraic.py
index 797fc4b..a1c18cc 100644
--- a/src/compiler/nir/nir_opt_algebraic.py
+++ b/src/compiler/nir/nir_opt_algebraic.py
@@ -513,6 +513,27 @@ for op in ['flt', 'fge', 'feq', 'fne',
('bcsel', 'a', (op, 'd', 'b'), (op, 'd', 'c'))),
]
+# This section contains "late" optimizations that should be run before
+# creating ffmas and calling regular optimizations for the final time.
+# Optimizations should go here if they help code generation and conflict
+# with the regular optimizations.
+before_ffma_optimizations = [
+ # Propagate constants down multiplication chains
+ (('fmul(is_used_once)', ('fmul(is_used_once)', 'a(is_not_const)', '#b'),
'c(is_not_const)'), ('fmul', ('fmul', a, c), b)),
+ (('imul(is_used_once)', ('imul(is_used_once)', 'a(is_not_const)', '#b'),
'c(is_not_const)'), ('imul', ('imul', a, c), b)),
+ (('fadd(is_used_once)', ('fadd(is_used_once)', 'a(is_not_const)', '#b'),
'c(is_not_const)'), ('fadd', ('fadd', a, c), b)),
+ (('iadd(is_used_once)', ('iadd(is_used_once)', 'a(is_not_const)', '#b'),
'c(is_not_const)'), ('iadd', ('iadd', a, c), b)),
+
+ (('~fadd', ('fmul', a, b), ('fmul', a, c)), ('fmul', a, ('fadd', b, c))),
+ (('iadd', ('imul', a, b), ('imul', a, c)), ('imul', a, ('iadd', b, c))),
+ (('~fadd', ('fneg', a), a), 0.0),
+ (('iadd', ('ineg', a), a), 0),
+ (('iadd', ('ineg', a), ('iadd', a, b)), b),
+ (('iadd', a, ('iadd', ('ineg', a), b)), b),
+ (('~fadd', ('fneg', a), ('fadd', a, b)), b),
+ (('~fadd', a, ('fadd', ('fneg', a), b)), b),
+]
+
# This section contains "late" optimizations that should be run after the
# regular optimizations have finished. Optimizations should go here if
# they help code generation but do not necessarily produce code that is
@@ -539,5 +560,7 @@ late_optimizations = [
]
print nir_algebraic.AlgebraicPass("nir_opt_algebraic", optimizations).render()
+print nir_algebraic.AlgebraicPass("nir_opt_algebraic_before_ffma",
+ before_ffma_optimizations).render()
print nir_algebraic.AlgebraicPass("nir_opt_algebraic_late",
late_optimizations).render()
diff --git a/src/mesa/drivers/dri/i965/brw_nir.c
b/src/mesa/drivers/dri/i965/brw_nir.c
index a5912a0..999e1d2 100644
--- a/src/mesa/drivers/dri/i965/brw_nir.c
+++ b/src/mesa/drivers/dri/i965/brw_nir.c
@@ -604,6 +604,12 @@ brw_postprocess_nir(nir_shader *nir, const struct
brw_compiler *compiler,
bool progress; /* Written by OPT and OPT_V */
(void)progress;
+
+ do {
+ progress = false;
+ OPT(nir_opt_algebraic_before_ffma);
+ } while (progress);
+
nir = nir_optimize(nir, compiler, is_scalar);
if (devinfo->gen >= 6) {
--
2.9.3
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev
