lima/gpir: kill dead writes to regs in DCE

Writes to regs that are never read will confuse regalloc since they
are never live and don't conflict with any regs. Kill them to prevent
overwriting another live reg.

Reviewed-by: Andreas Baierl <ichgeh@imkreisrum.de>
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4125>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4125>

diff --git a/.gitlab-ci/deqp-lima-fails.txt b/.gitlab-ci/deqp-lima-fails.txt
index 10915b9745acd86273ce3c559a7a4e038304f724..c6d1cf56ecd3569dd5842831263e8ca2670e10bc 100644 (file)
--- a/.gitlab-ci/deqp-lima-fails.txt
+++ b/.gitlab-ci/deqp-lima-fails.txt
@@ -69,19 +69,9 @@ dEQP-GLES2.functional.shaders.functions.qualifiers.inout_lowp_int_vertex
 dEQP-GLES2.functional.shaders.functions.qualifiers.out_highp_int_vertex
 dEQP-GLES2.functional.shaders.functions.qualifiers.out_int_vertex
 dEQP-GLES2.functional.shaders.functions.qualifiers.out_lowp_int_vertex
-dEQP-GLES2.functional.shaders.indexing.matrix_subscript.mat3_dynamic_loop_write_static_loop_read_vertex
-dEQP-GLES2.functional.shaders.indexing.matrix_subscript.mat3_dynamic_loop_write_static_read_vertex
-dEQP-GLES2.functional.shaders.indexing.matrix_subscript.mat3_dynamic_write_dynamic_loop_read_vertex
-dEQP-GLES2.functional.shaders.loops.do_while_constant_iterations.conditional_body_vertex
 dEQP-GLES2.functional.shaders.loops.do_while_dynamic_iterations.vector_counter_fragment
-dEQP-GLES2.functional.shaders.loops.do_while_uniform_iterations.conditional_body_vertex
-dEQP-GLES2.functional.shaders.loops.do_while_uniform_iterations.nested_tricky_dataflow_2_vertex
 dEQP-GLES2.functional.shaders.loops.for_dynamic_iterations.vector_counter_fragment
-dEQP-GLES2.functional.shaders.loops.while_constant_iterations.compound_statement_vertex
-dEQP-GLES2.functional.shaders.loops.while_constant_iterations.sequence_statement_vertex
-dEQP-GLES2.functional.shaders.loops.while_dynamic_iterations.nested_sequence_vertex
 dEQP-GLES2.functional.shaders.loops.while_dynamic_iterations.vector_counter_fragment
-dEQP-GLES2.functional.shaders.loops.while_uniform_iterations.nested_vertex
 dEQP-GLES2.functional.shaders.operator.binary_operator.sub_assign_effect.highp_int_vertex
 dEQP-GLES2.functional.shaders.operator.binary_operator.sub_assign_effect.highp_ivec2_int_vertex
 dEQP-GLES2.functional.shaders.operator.binary_operator.sub_assign_effect.highp_ivec2_vertex

diff --git a/.gitlab-ci/deqp-lima-skips.txt b/.gitlab-ci/deqp-lima-skips.txt
index 0ee0188885eec576b0cfcd0e5eb2b46ec1370371..83b241f34d1fdbc440c088fe370699e5e45b0fb1 100644 (file)
--- a/.gitlab-ci/deqp-lima-skips.txt
+++ b/.gitlab-ci/deqp-lima-skips.txt
@@ -26,18 +26,11 @@ dEQP-GLES2.functional.shaders.random.all_features.fragment.55
 dEQP-GLES2.functional.shaders.random.trigonometric.fragment.1
 dEQP-GLES2.functional.shaders.random.trigonometric.fragment.69
 
-# Driver bugs causing GPU errors
-dEQP-GLES2.functional.shaders.loops.while_constant_iterations.nested_sequence_vertex
-dEQP-GLES2.functional.shaders.loops.while_constant_iterations.conditional_body_vertex
-dEQP-GLES2.functional.shaders.loops.while_uniform_iterations.conditional_continue_vertex
-dEQP-GLES2.functional.shaders.loops.while_uniform_iterations.double_continue_vertex
-
 # Hangs / OOM
 dEQP-GLES2.functional.shaders.indexing.varying_array.vec4_dynamic_loop_write_static_read
 dEQP-GLES2.functional.shaders.indexing.varying_array.vec4_dynamic_loop_write_dynamic_read
 dEQP-GLES2.functional.shaders.indexing.varying_array.vec4_dynamic_loop_write_static_loop_read
 dEQP-GLES2.functional.shaders.indexing.varying_array.vec4_dynamic_loop_write_dynamic_loop_read
-dEQP-GLES2.functional.shaders.indexing.tmp_array.vec3_dynamic_loop_write_dynamic_read_vertex
 
 dEQP-GLES2.functional.shaders.indexing.tmp_array.vec4_dynamic_loop_write_static_read_vertex
 dEQP-GLES2.functional.shaders.indexing.tmp_array.vec4_dynamic_loop_write_dynamic_read_vertex

diff --git a/src/gallium/drivers/lima/ir/gp/optimize.c b/src/gallium/drivers/lima/ir/gp/optimize.c
index afa10ec05140741dfc1fe80439a23952d72b9565..c95faec9c6d5af37780aeb35830556b34a0cd921 100644 (file)
--- a/src/gallium/drivers/lima/ir/gp/optimize.c
+++ b/src/gallium/drivers/lima/ir/gp/optimize.c
@@ -171,6 +171,34 @@ dead_code_eliminate(gpir_compiler *comp)
          }
       }
    }
+
+   /* Kill all the writes to regs that are never read. All the known
+    * instances of these are coming from the cycle-breaking register
+    * created in out-of-SSA. See resolve_parallel_copy() in nir_from_ssa.c
+    * Since we kill redundant movs when we translate nir into gpir, it
+    * results in this reg being written, but never read.
+    */
+   BITSET_WORD *regs = rzalloc_array(comp, BITSET_WORD, comp->cur_reg);
+   list_for_each_entry(gpir_block, block, &comp->block_list, list) {
+      list_for_each_entry(gpir_node, node, &block->node_list, list) {
+         if (node->op != gpir_op_load_reg)
+            continue;
+         gpir_load_node *load = gpir_node_to_load(node);
+         BITSET_SET(regs, load->reg->index);
+      }
+   }
+
+   list_for_each_entry(gpir_block, block, &comp->block_list, list) {
+      list_for_each_entry_safe(gpir_node, node, &block->node_list, list) {
+         if (node->op != gpir_op_store_reg)
+            continue;
+         gpir_store_node *store = gpir_node_to_store(node);
+         if (!BITSET_TEST(regs, store->reg->index))
+            gpir_node_delete(node);
+      }
+   }
+
+   ralloc_free(regs);
 }
 
 bool