nir/opt_algebraic: remove is_used_once on outer instruction

This just prevents useful optimizations.
is_used_once only makes sense on inner instructions, to prevent
creating more new instructions than will be removed.

Foz-DB Navi48:
Totals from 16989 (14.82% of 114655) affected shaders:
MaxWaves: 434379 -> 434353 (-0.01%); split: +0.01%, -0.01%
Instrs: 29030794 -> 29022514 (-0.03%); split: -0.07%, +0.04%
CodeSize: 155293092 -> 155262816 (-0.02%); split: -0.05%, +0.03%
VGPRs: 1093980 -> 1094088 (+0.01%); split: -0.01%, +0.02%
SpillSGPRs: 9801 -> 9803 (+0.02%); split: -0.03%, +0.05%
Latency: 356327270 -> 356283384 (-0.01%); split: -0.03%, +0.02%
InvThroughput: 58239439 -> 58229374 (-0.02%); split: -0.03%, +0.01%
VClause: 451716 -> 451815 (+0.02%); split: -0.07%, +0.09%
SClause: 654614 -> 654556 (-0.01%); split: -0.03%, +0.03%
Copies: 1809805 -> 1809297 (-0.03%); split: -0.20%, +0.17%
Branches: 552382 -> 552384 (+0.00%); split: -0.00%, +0.00%
PreSGPRs: 947188 -> 947224 (+0.00%); split: -0.01%, +0.02%
PreVGPRs: 879583 -> 880173 (+0.07%); split: -0.01%, +0.08%
VALU: 16317859 -> 16309975 (-0.05%); split: -0.07%, +0.02%
SALU: 4256121 -> 4259315 (+0.08%); split: -0.05%, +0.12%
SMEM: 1067069 -> 1067070 (+0.00%)
VOPD: 440855 -> 440792 (-0.01%); split: +0.05%, -0.07%

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40138>
This commit is contained in:
Georg Lehmann 2026-03-01 13:21:40 +01:00 committed by Marge Bot
parent 41878e5714
commit 3d304d5647

View file

@ -2324,19 +2324,19 @@ optimizations.extend([
(('imul', ('ineg', a), b), ('ineg', ('imul', a, b))),
# Propagate constants up multiplication chains
(('~fmul(is_used_once)', ('fmul(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fmul', ('fmul', a, c), b)),
(('~fmulz(is_used_once)', ('fmulz(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fmulz', ('fmulz', a, c), b)),
(('~fmul(is_used_once)', ('fmulz(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c(is_finite_not_zero)'), ('fmulz', ('fmul', a, c), b)),
(('imul(is_used_once)', ('imul(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('imul', ('imul', a, c), b)),
(('~fmul', ('fmul(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fmul', ('fmul', a, c), b)),
(('~fmulz', ('fmulz(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fmulz', ('fmulz', a, c), b)),
(('~fmul', ('fmulz(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c(is_finite_not_zero)'), ('fmulz', ('fmul', a, c), b)),
(('imul', ('imul(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('imul', ('imul', a, c), b)),
(('~ffma', ('fmul(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c', d), ('ffma', ('fmul', a, c), b, d)),
(('~ffmaz', ('fmulz(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c', d), ('ffmaz', ('fmulz', a, c), b, d)),
(('~ffma', ('fmulz(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c(is_finite_not_zero)', d), ('ffmaz', ('fmul', a, c), b, d)),
# Prefer moving out a multiplication for more MAD/FMA-friendly code
(('~fadd(is_used_once)', ('fadd(is_used_once)', 'a(is_not_const)', 'b(is_fmul)'), '#c'), ('fadd', ('fadd', a, c), b)),
(('~fadd(is_used_once)', ('fadd(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fadd', ('fadd', a, c), b)),
(('~fadd(is_used_once)', ('ffma(is_used_once)', 'a(is_not_const)', b, 'c(is_not_const)'), '#d'), ('fadd', ('ffma', a, b, d), c)),
(('~fadd(is_used_once)', ('ffmaz(is_used_once)', 'a(is_not_const)', b, 'c(is_not_const)'), '#d'), ('fadd', ('ffmaz', a, b, d), c)),
(('iadd(is_used_once)', ('iadd(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('iadd', ('iadd', a, c), b)),
(('~fadd', ('fadd(is_used_once)', 'a(is_not_const)', 'b(is_fmul)'), '#c'), ('fadd', ('fadd', a, c), b)),
(('~fadd', ('fadd(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('fadd', ('fadd', a, c), b)),
(('~fadd', ('ffma(is_used_once)', 'a(is_not_const)', b, 'c(is_not_const)'), '#d'), ('fadd', ('ffma', a, b, d), c)),
(('~fadd', ('ffmaz(is_used_once)', 'a(is_not_const)', b, 'c(is_not_const)'), '#d'), ('fadd', ('ffmaz', a, b, d), c)),
(('iadd', ('iadd(is_used_once)', 'a(is_not_const)', 'b(is_not_const)'), '#c'), ('iadd', ('iadd', a, c), b)),
# Reassociate constants in add/mul chains so they can be folded together.
# For now, we mostly only handle cases where the constants are separated by
@ -3527,10 +3527,10 @@ for i in range(2, 4 + 1):
# 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)),
(('~fmul', ('fmul(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('fmul', ('fmul', a, c), b)),
(('imul', ('imul(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('imul', ('imul', a, c), b)),
(('~fadd', ('fadd(is_used_once)', 'a(is_not_const)', '#b'), 'c(is_not_const)'), ('fadd', ('fadd', a, c), b)),
(('iadd', ('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))),