From 1fb24080b7da8c1378c7aabc2d02ffece677ce7c Mon Sep 17 00:00:00 2001 From: "Juan A. Suarez Romero" Date: Tue, 12 Feb 2019 12:02:42 +0000 Subject: [PATCH] nir: remove jump from two merging jump-ending blocks In opt_peel_initial_if optimization, when moving the continue list to end of the continue block, before the jump, could happen that the continue list itself also ends with a jump. This would mean that we would have two jump instructions in a row: the first one from the continue list and the second one from the contine block. As inserting an instruction after a jump is not allowed (and it does not make sense, as it will not be executed), remove the jump from the continue block and keep the one from continue list, as it will be executed first. CC: Jason Ekstrand Reviewed-by: Caio Marcelo de Oliveira Filho --- src/compiler/nir/nir_opt_if.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/src/compiler/nir/nir_opt_if.c b/src/compiler/nir/nir_opt_if.c index 60846de..bc128f7 100644 --- a/src/compiler/nir/nir_opt_if.c +++ b/src/compiler/nir/nir_opt_if.c @@ -241,12 +241,29 @@ opt_peel_loop_initial_if(nir_loop *loop) nir_cf_reinsert(&header, nir_after_block_before_jump(find_continue_block(loop))); + bool continue_list_jumps = + nir_block_ends_in_jump(exec_node_data(nir_block, + exec_list_get_tail(continue_list), + cf_node.node)); + nir_cf_extract(&tmp, nir_before_cf_list(continue_list), nir_after_cf_list(continue_list)); - /* Get continue block again as the previous reinsert might have removed the block. */ + /* Get continue block again as the previous reinsert might have removed the + * block. Also, if both the continue list and the continue block ends in + * jump instructions, removes the jump from the latter, as it will not be + * executed if we insert the continue list before it. */ + + nir_block *continue_block = find_continue_block(loop); + + if (continue_list_jumps) { + nir_instr *last_instr = nir_block_last_instr(continue_block); + if (last_instr && last_instr->type == nir_instr_type_jump) + nir_instr_remove(last_instr); + } + nir_cf_reinsert(&tmp, - nir_after_block_before_jump(find_continue_block(loop))); + nir_after_block_before_jump(continue_block)); nir_cf_node_remove(&nif->cf_node); -- 2.7.4