From 47bd462b0caa46a2dd1fb88e57f6a968aff6cfc4 Mon Sep 17 00:00:00 2001 From: Connor Abbott Date: Wed, 3 Jun 2015 14:10:28 -0400 Subject: [PATCH] awesome control flow bugfixes/clarifications --- src/glsl/nir/spirv_to_nir.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/src/glsl/nir/spirv_to_nir.c b/src/glsl/nir/spirv_to_nir.c index 1fc1b8b..979df20 100644 --- a/src/glsl/nir/spirv_to_nir.c +++ b/src/glsl/nir/spirv_to_nir.c @@ -1355,20 +1355,11 @@ vtn_walk_blocks(struct vtn_builder *b, struct vtn_block *start, { struct vtn_block *block = start; while (block != end_block) { - if (block->block != NULL) { - /* We've already visited this block once before so this is a - * back-edge. Back-edges are only allowed to point to a loop - * merge. - */ - assert(block == cont_block); - return; - } - if (block->merge_op == SpvOpLoopMerge) { /* This is the jump into a loop. */ - cont_block = block; - break_block = vtn_value(b, block->merge_block_id, - vtn_value_type_block)->block; + struct vtn_block *new_cont_block = block; + struct vtn_block *new_break_block = + vtn_value(b, block->merge_block_id, vtn_value_type_block)->block; nir_loop *loop = nir_loop_create(b->shader); nir_cf_node_insert_end(b->nb.cf_node_list, &loop->cf_node); @@ -1379,7 +1370,7 @@ vtn_walk_blocks(struct vtn_builder *b, struct vtn_block *start, block->merge_op = SpvOpNop; nir_builder_insert_after_cf_list(&b->nb, &loop->body); - vtn_walk_blocks(b, block, break_block, cont_block, NULL); + vtn_walk_blocks(b, block, new_break_block, new_cont_block, NULL); nir_builder_insert_after_cf_list(&b->nb, old_list); block = break_block; @@ -1411,8 +1402,16 @@ vtn_walk_blocks(struct vtn_builder *b, struct vtn_block *start, return; } else if (branch_block == end_block) { + /* We're branching to the merge block of an if, since for loops + * and functions end_block == NULL, so we're done here. + */ return; } else { + /* We're branching to another block, and according to the rules, + * we can only branch to another block with one predecessor (so + * we're the only one jumping to it) so we can just process it + * next. + */ block = branch_block; continue; } @@ -1454,7 +1453,10 @@ vtn_walk_blocks(struct vtn_builder *b, struct vtn_block *start, &jump->instr); block = then_block; } else { - /* Conventional if statement */ + /* According to the rules we're branching to two blocks that don't + * have any other predecessors, so we can handle this as a + * conventional if. + */ assert(block->merge_op == SpvOpSelectionMerge); struct vtn_block *merge_block = vtn_value(b, block->merge_block_id, vtn_value_type_block)->block; -- 2.7.4