From a801196ec9c200318a667021d1b4e0820228a507 Mon Sep 17 00:00:00 2001 From: Timothy Arceri Date: Thu, 14 Feb 2019 12:27:25 +1100 Subject: [PATCH] nir: remove simple dead if detection from nir_opt_dead_cf() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This was probably useful when it was first written, however it looks to be no longer necessary. As far as I can tell these days dce is smart enough to remove useless instructions from if branches. Once this is done nir_opt_peephole_select() will end up removing the empty if. Removing this support reduces the dolphin uber shader compilation time spent in nir_opt_dead_cf() by a little over 7x. No shader-db changes on i965 or radeonsi. Tested-by: Dieter Nützel Reviewed-by: Jason Ekstrand Reviewed-by: Connor Abbott --- src/compiler/nir/nir_opt_dead_cf.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/src/compiler/nir/nir_opt_dead_cf.c b/src/compiler/nir/nir_opt_dead_cf.c index e796e6e85e3..4cacfed1119 100644 --- a/src/compiler/nir/nir_opt_dead_cf.c +++ b/src/compiler/nir/nir_opt_dead_cf.c @@ -164,7 +164,7 @@ def_only_used_in_cf_node(nir_ssa_def *def, void *_node) } /* - * Test if a loop node or if node is dead. Such nodes are dead if: + * Test if a loop node is dead. Such nodes are dead if: * * 1) It has no side effects (i.e. intrinsics which could possibly affect the * state of the program aside from producing an SSA value, indicated by a lack @@ -182,7 +182,7 @@ def_only_used_in_cf_node(nir_ssa_def *def, void *_node) static bool node_is_dead(nir_cf_node *node) { - assert(node->type == nir_cf_node_loop || node->type == nir_cf_node_if); + assert(node->type == nir_cf_node_loop); nir_block *after = nir_cf_node_as_block(nir_cf_node_next(node)); @@ -239,11 +239,6 @@ dead_cf_block(nir_block *block) { nir_if *following_if = nir_block_get_following_if(block); if (following_if) { - if (node_is_dead(&following_if->cf_node)) { - nir_cf_node_remove(&following_if->cf_node); - return true; - } - if (!nir_src_is_const(following_if->condition)) return false; -- 2.30.2