From 5ff1e446d44bb9d50f84883c7058635cb070e069 Mon Sep 17 00:00:00 2001 From: Matt Turner Date: Wed, 9 Apr 2014 14:31:10 -0700 Subject: [PATCH] i965/fs: Simplify interference scan in register coalescing. We were starting at the beginning of the instruction list, rather than with the MOV instruction itself. This allows us to coalesce after control flow. Excluding the shaders from an unreleased title, the shader-db results: total instructions in shared programs: 1603791 -> 1594215 (-0.60%) instructions in affected programs: 678772 -> 669196 (-1.41%) GAINED: 5 LOST: 0 Reviewed-by: Kenneth Graunke --- .../dri/i965/brw_fs_register_coalesce.cpp | 22 ++++++++----------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp b/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp index 01b672f36dd..020d992b15a 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp @@ -77,7 +77,7 @@ is_coalesce_candidate(const fs_inst *inst, const int *virtual_grf_sizes) static bool can_coalesce_vars(brw::fs_live_variables *live_intervals, - const exec_list *instructions, const fs_inst *inst, + const exec_list *instructions, const fs_inst *inst, int ip, int var_to, int var_from) { if (!live_intervals->vars_interfere(var_from, var_to)) @@ -96,21 +96,15 @@ can_coalesce_vars(brw::fs_live_variables *live_intervals, if (live_intervals->end[var_to] > live_intervals->end[var_from]) return false; - int scan_ip = -1; - - foreach_list(n, instructions) { - fs_inst *scan_inst = (fs_inst *)n; - scan_ip++; + assert(ip >= live_intervals->start[var_to]); + fs_inst *scan_inst; + for (scan_inst = (fs_inst *)inst->next; + !scan_inst->is_tail_sentinel() && ip <= live_intervals->end[var_to]; + scan_inst = (fs_inst *)scan_inst->next, ip++) { if (scan_inst->is_control_flow()) return false; - if (scan_ip <= live_intervals->start[var_to]) - continue; - - if (scan_ip > live_intervals->end[var_to]) - break; - if (scan_inst->dst.equals(inst->dst) || scan_inst->dst.equals(inst->src[0])) return false; @@ -133,9 +127,11 @@ fs_visitor::register_coalesce() fs_inst *mov[MAX_SAMPLER_MESSAGE_SIZE]; int var_to[MAX_SAMPLER_MESSAGE_SIZE]; int var_from[MAX_SAMPLER_MESSAGE_SIZE]; + int ip = -1; foreach_list(node, &this->instructions) { fs_inst *inst = (fs_inst *)node; + ip++; if (!is_coalesce_candidate(inst, virtual_grf_sizes)) continue; @@ -174,7 +170,7 @@ fs_visitor::register_coalesce() var_to[i] = live_intervals->var_from_vgrf[reg_to] + reg_to_offset[i]; var_from[i] = live_intervals->var_from_vgrf[reg_from] + i; - if (!can_coalesce_vars(live_intervals, &instructions, inst, + if (!can_coalesce_vars(live_intervals, &instructions, inst, ip, var_to[i], var_from[i])) { can_coalesce = false; reg_from = -1; -- 2.30.2