diff options
| -rw-r--r-- | src/mesa/drivers/dri/i965/brw_fs.cpp | 52 |
1 files changed, 50 insertions, 2 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index 6106445fbb7..472e6d06f62 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp @@ -455,6 +455,7 @@ public: void assign_regs(); void assign_regs_trivial(); void calculate_live_intervals(); + bool dead_code_eliminate(); bool virtual_grf_interferes(int a, int b); void generate_code(); void generate_fb_write(fs_inst *inst); @@ -2289,8 +2290,6 @@ fs_visitor::assign_regs() int class_count = 0; int aligned_pair_class = -1; - calculate_live_intervals(); - /* Set up the register classes. * * The base registers store a scalar value. For texture samples, @@ -2517,10 +2516,50 @@ fs_visitor::calculate_live_intervals() ip++; } + talloc_free(this->virtual_grf_def); + talloc_free(this->virtual_grf_use); this->virtual_grf_def = def; this->virtual_grf_use = use; } +/** + * Must be called after calculate_live_intervales() to remove unused + * writes to registers -- register allocation will fail otherwise + * because something deffed but not used won't be considered to + * interfere with other regs. + */ +bool +fs_visitor::dead_code_eliminate() +{ + bool progress = false; + int num_vars = this->virtual_grf_next; + bool dead[num_vars]; + + for (int i = 0; i < num_vars; i++) { + /* This would be ">=", but FS_OPCODE_DISCARD has a src == dst where + * it writes dst then reads it as src. + */ + dead[i] = this->virtual_grf_def[i] > this->virtual_grf_use[i]; + + if (dead[i]) { + /* Mark off its interval so it won't interfere with anything. */ + this->virtual_grf_def[i] = -1; + this->virtual_grf_use[i] = -1; + } + } + + foreach_iter(exec_list_iterator, iter, this->instructions) { + fs_inst *inst = (fs_inst *)iter.get(); + + if (inst->dst.file == GRF && dead[inst->dst.reg]) { + inst->remove(); + progress = true; + } + } + + return progress; +} + bool fs_visitor::virtual_grf_interferes(int a, int b) { @@ -2831,6 +2870,15 @@ brw_wm_fs_emit(struct brw_context *brw, struct brw_wm_compile *c) v.emit_fb_writes(); v.assign_curb_setup(); v.assign_urb_setup(); + + bool progress; + do { + progress = false; + + v.calculate_live_intervals(); + progress = v.dead_code_eliminate() || progress; + } while (progress); + if (0) v.assign_regs_trivial(); else |