From 2c643fd978c43205b9620820038ba6246ed045e2 Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Wed, 14 Mar 2018 16:25:07 -0700 Subject: [PATCH] nir: Don't condition 'a-b < 0' -> 'a < b' on is_not_used_by_conditional MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Now that i965 recognizes that a-b generates the same conditions as 'a < b', there is no reason to condition this transformation on 'is not used by conditional.' Since this was the only user of the is_not_used_by_conditional function, delete it. All Gen6+ platforms had similar results. (Skylake shown) total instructions in shared programs: 14400775 -> 14400595 (<.01%) instructions in affected programs: 36712 -> 36532 (-0.49%) helped: 182 HURT: 26 helped stats (abs) min: 1 max: 2 x̄: 1.13 x̃: 1 helped stats (rel) min: 0.15% max: 1.82% x̄: 0.70% x̃: 0.62% HURT stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1 HURT stats (rel) min: 0.24% max: 1.02% x̄: 0.82% x̃: 0.90% 95% mean confidence interval for instructions value: -0.97 -0.76 95% mean confidence interval for instructions %-change: -0.59% -0.43% Instructions are helped. total cycles in shared programs: 532929592 -> 532926345 (<.01%) cycles in affected programs: 478660 -> 475413 (-0.68%) helped: 187 HURT: 22 helped stats (abs) min: 2 max: 200 x̄: 20.99 x̃: 18 helped stats (rel) min: 0.23% max: 24.10% x̄: 1.48% x̃: 1.03% HURT stats (abs) min: 1 max: 214 x̄: 30.86 x̃: 11 HURT stats (rel) min: 0.01% max: 23.06% x̄: 3.12% x̃: 0.86% 95% mean confidence interval for cycles value: -19.50 -11.57 95% mean confidence interval for cycles %-change: -1.42% -0.58% Cycles are helped. GM45 and Iron Lake had similar results. (Iron Lake shown) total cycles in shared programs: 177851578 -> 177851810 (<.01%) cycles in affected programs: 24408 -> 24640 (0.95%) helped: 2 HURT: 4 helped stats (abs) min: 4 max: 4 x̄: 4.00 x̃: 4 helped stats (rel) min: 0.42% max: 0.47% x̄: 0.44% x̃: 0.44% HURT stats (abs) min: 24 max: 108 x̄: 60.00 x̃: 54 HURT stats (rel) min: 0.52% max: 1.62% x̄: 1.04% x̃: 1.02% 95% mean confidence interval for cycles value: -7.75 85.08 95% mean confidence interval for cycles %-change: -0.39% 1.49% Inconclusive result (value mean confidence interval includes 0). Signed-off-by: Ian Romanick Reviewed-by: Matt Turner --- src/compiler/nir/nir_opt_algebraic.py | 4 +--- src/compiler/nir/nir_search_helpers.h | 15 --------------- 2 files changed, 1 insertion(+), 18 deletions(-) diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py index b9565cea7b7..96232f0e549 100644 --- a/src/compiler/nir/nir_opt_algebraic.py +++ b/src/compiler/nir/nir_opt_algebraic.py @@ -208,9 +208,7 @@ optimizations = [ # fmax. If b is > 1.0, the bcsel will be replaced with a b2f. (('fmin', ('b2f', a), '#b'), ('bcsel', a, ('fmin', b, 1.0), ('fmin', b, 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)), + (('flt', ('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)), diff --git a/src/compiler/nir/nir_search_helpers.h b/src/compiler/nir/nir_search_helpers.h index 2e3bd137d6d..2d399bd5dcd 100644 --- a/src/compiler/nir/nir_search_helpers.h +++ b/src/compiler/nir/nir_search_helpers.h @@ -170,19 +170,4 @@ 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_ */ -- 2.30.2