From 4decc426c26a86beb76dc48658ce175d051464c2 Mon Sep 17 00:00:00 2001 From: Francisco Jerez Date: Wed, 25 May 2016 14:21:49 -0700 Subject: [PATCH] i965/fs: Skip gen4 pre/post-send dependency workaronds for the first/last block. We know that there cannot be any destination dependency race if we reach the beginning or end of the program without having found any other instruction the send could possibly race with. This avoids emitting a pile of useless moves at the beginning or end of the program in the most common case in which the program has a single basic block only. On the original i965 I get the following shader-db results: total instructions in shared programs: 3354165 -> 3215637 (-4.13%) instructions in affected programs: 3183065 -> 3044537 (-4.35%) helped: 13498 HURT: 0 Reviewed-by: Jason Ekstrand --- src/mesa/drivers/dri/i965/brw_fs.cpp | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp index 1b484228e34..d04eebc024c 100644 --- a/src/mesa/drivers/dri/i965/brw_fs.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp @@ -3163,7 +3163,7 @@ fs_visitor::insert_gen4_pre_send_dependency_workarounds(bblock_t *block, /* If we hit control flow, assume that there *are* outstanding * dependencies, and force their cleanup before our instruction. */ - if (block->start() == scan_inst) { + if (block->start() == scan_inst && block->num != 0) { for (int i = 0; i < write_len; i++) { if (needs_dep[i]) DEP_RESOLVE_MOV(fs_builder(this, block, inst), @@ -3227,7 +3227,7 @@ fs_visitor::insert_gen4_post_send_dependency_workarounds(bblock_t *block, fs_ins */ foreach_inst_in_block_starting_from(fs_inst, scan_inst, inst) { /* If we hit control flow, force resolve all remaining dependencies. */ - if (block->end() == scan_inst) { + if (block->end() == scan_inst && block->num != cfg->num_blocks - 1) { for (int i = 0; i < write_len; i++) { if (needs_dep[i]) DEP_RESOLVE_MOV(fs_builder(this, block, scan_inst),