panfrost/midgard: Copy prop for texture registers

We'll want to unify this with main copy prop (and extend to varyings),
but that'll take more care to handle some special cases, so leave it as
a stub pass for now.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>

diff --git a/src/gallium/drivers/panfrost/midgard/midgard_compile.c b/src/gallium/drivers/panfrost/midgard/midgard_compile.c
index b5ab103..72455c7 100644 (file)
--- a/src/gallium/drivers/panfrost/midgard/midgard_compile.c
+++ b/src/gallium/drivers/panfrost/midgard/midgard_compile.c
@@ -1788,8 +1788,6 @@ emit_tex(compiler_context *ctx, nir_tex_instr *instr)
                                 emit_mir_instruction(ctx, ins);
                         }
 
-                        //midgard_pin_output(ctx, index, REGISTER_TEXTURE_BASE + in_reg);
-
                         break;
                 }
 
@@ -3220,6 +3218,40 @@ midgard_opt_copy_prop(compiler_context *ctx, midgard_block *block)
         return progress;
 }
 
+static bool
+midgard_opt_copy_prop_tex(compiler_context *ctx, midgard_block *block)
+{
+        bool progress = false;
+
+        mir_foreach_instr_in_block_safe(block, ins) {
+                if (ins->type != TAG_ALU_4) continue;
+                if (!OP_IS_MOVE(ins->alu.op)) continue;
+
+                unsigned from = ins->ssa_args.src1;
+                unsigned to = ins->ssa_args.dest;
+
+                /* Make sure it's a familiar type of special move. Basically we
+                 * just handle the special dummy moves emitted by the texture
+                 * pipeline. TODO: verify. TODO: why does this break varyings?
+                 */
+
+                if (from >= SSA_FIXED_MINIMUM) continue;
+                if (to < SSA_FIXED_REGISTER(REGISTER_TEXTURE_BASE)) continue;
+                if (to > SSA_FIXED_REGISTER(REGISTER_TEXTURE_BASE + 1)) continue;
+
+                mir_foreach_instr_in_block_from_rev(block, v, mir_prev_op(ins)) {
+                        if (v->ssa_args.dest == from) {
+                                v->ssa_args.dest = to;
+                                progress = true;
+                        }
+                }
+
+                mir_remove_instruction(ins);
+        }
+
+        return progress;
+}
+
 /* The following passes reorder MIR instructions to enable better scheduling */
 
 static void
@@ -3769,6 +3801,7 @@ midgard_compile_shader_nir(nir_shader *nir, midgard_program *program, bool is_bl
 
                 mir_foreach_block(ctx, block) {
                         progress |= midgard_opt_copy_prop(ctx, block);
+                        progress |= midgard_opt_copy_prop_tex(ctx, block);
                         progress |= midgard_opt_dead_code_eliminate(ctx, block);
                 }
         } while (progress);