From f1168c53aedea36a28926f5e04e4e4bc92683ef4 Mon Sep 17 00:00:00 2001 From: Emma Anholt Date: Mon, 11 Apr 2022 16:28:05 -0700 Subject: [PATCH] nir: Add lowering for fround_even on r300. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When we put NIR in the compiler stack for r300, indirect addressing broke for gallium nine. DX's array indirects round the float value, so the DX shader gets mapped to a TGSI "ARR ADDR[0] src.x" instruction. Translating that to NIR maps to r0[f2i32(fround(src.x))]. While we might hope that in translation back using nir-to-tgsi after optimization we would recognize the construct and emit ARR again, that's going to be error prone (think "what if src.x is in a NIR register?") so we need a fallback plan. r300 will be able to handle this lowering, so get it in place first to fix the regression. Fixes: #6297 Fixes: 7d2ea9b0edef ("r300: Request NIR shaders from mesa/st and use NIR-to-TGSI.") Reviewed-by: Marek Olšák Part-of: (cherry picked from commit 6947016b468417f60203db68c34e0961e4ac7845) --- .pick_status.json | 2 +- src/compiler/nir/nir.h | 8 ++++++++ src/compiler/nir/nir_opt_algebraic.py | 8 ++++++++ src/gallium/drivers/r300/r300_screen.c | 4 ++++ 4 files changed, 21 insertions(+), 1 deletion(-) diff --git a/.pick_status.json b/.pick_status.json index 3d605be27db..83cfa0a68e5 100644 --- a/.pick_status.json +++ b/.pick_status.json @@ -1408,7 +1408,7 @@ "description": "nir: Add lowering for fround_even on r300.", "nominated": true, "nomination_type": 1, - "resolution": 0, + "resolution": 1, "main_sha": null, "because_sha": "7d2ea9b0edef2176140629ac3dee6a6809c4abe2" }, diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h index 45ca5789825..29ed6820f3f 100644 --- a/src/compiler/nir/nir.h +++ b/src/compiler/nir/nir.h @@ -3286,6 +3286,14 @@ typedef struct nir_shader_compiler_options { bool lower_ftrunc; + /** Lowers fround_even to ffract+feq+csel. + * + * Not correct in that it doesn't correctly handle the "_even" part of the + * rounding, but good enough for DX9 array indexing handling on DX9-class + * hardware. + */ + bool lower_fround_even; + bool lower_ldexp; bool lower_pack_half_2x16; diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py index 54be7f7195d..35f445afd5e 100644 --- a/src/compiler/nir/nir_opt_algebraic.py +++ b/src/compiler/nir/nir_opt_algebraic.py @@ -356,6 +356,14 @@ optimizations.extend([ (('~flrp', a, 0.0, c), ('fadd', ('fmul', ('fneg', a), c), a)), (('ftrunc', a), ('bcsel', ('flt', a, 0.0), ('fneg', ('ffloor', ('fabs', a))), ('ffloor', ('fabs', a))), 'options->lower_ftrunc'), + + # Approximate handling of fround_even for DX9 addressing from gallium nine on + # DX9-class hardware with no proper fround support. + (('fround_even', a), ('bcsel', + ('feq', ('ffract', a), 0.5), + ('fadd', ('ffloor', ('fadd', a, 0.5)), 1.0), + ('ffloor', ('fadd', a, 0.5))), 'options->lower_fround_even'), + (('ffloor', a), ('fsub', a, ('ffract', a)), 'options->lower_ffloor'), (('fadd', a, ('fneg', ('ffract', a))), ('ffloor', a), '!options->lower_ffloor'), (('ffract', a), ('fsub', a, ('ffloor', a)), 'options->lower_ffract'), diff --git a/src/gallium/drivers/r300/r300_screen.c b/src/gallium/drivers/r300/r300_screen.c index 40f5e5c0a5a..64d9135d54b 100644 --- a/src/gallium/drivers/r300/r300_screen.c +++ b/src/gallium/drivers/r300/r300_screen.c @@ -514,6 +514,7 @@ static const nir_shader_compiler_options r500_vs_compiler_options = { .lower_flrp32 = true, .lower_flrp64 = true, .lower_fmod = true, + .lower_fround_even = true, .lower_rotate = true, .lower_uniforms_to_ubo = true, .lower_vector_cmp = true, @@ -541,6 +542,7 @@ static const nir_shader_compiler_options r500_fs_compiler_options = { .lower_flrp32 = true, .lower_flrp64 = true, .lower_fmod = true, + .lower_fround_even = true, .lower_rotate = true, .lower_uniforms_to_ubo = true, .lower_vector_cmp = true, @@ -568,6 +570,7 @@ static const nir_shader_compiler_options r300_vs_compiler_options = { .lower_flrp32 = true, .lower_flrp64 = true, .lower_fmod = true, + .lower_fround_even = true, .lower_rotate = true, .lower_uniforms_to_ubo = true, .lower_vector_cmp = true, @@ -594,6 +597,7 @@ static const nir_shader_compiler_options r300_fs_compiler_options = { .lower_flrp32 = true, .lower_flrp64 = true, .lower_fmod = true, + .lower_fround_even = true, .lower_rotate = true, .lower_uniforms_to_ubo = true, .lower_vector_cmp = true,