Module: Mesa Branch: staging/19.1 Commit: a6de028a5a719f36968c372561f4213be8410f7b URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=a6de028a5a719f36968c372561f4213be8410f7b
Author: Jason Ekstrand <[email protected]> Date: Mon Sep 9 13:38:37 2019 -0500 nir/repair_ssa: Replace the unreachable check with the phi builder In a3268599f3c9, I attempted to fix nir_repair_ssa for unreachable blocks. However, that commit missed the possibility that the use is in a block which, itself, is unreachable. In this case, we can end up in an infinite loop trying to replace a def with itself. Even though a no-op replacement is a fine operation, it keeps extending the end of the uses list as we're walking it. Instead of explicitly checking for the group of conditions, just check if the phi builder gives us a different def. That's guaranteed to be 100% reliable and, while it lacks symmetry with the is_valid checks, should be more reliable. Fixes: a3268599 "nir/repair_ssa: Repair dominance for unreachable..." Reviewed-by: Ian Romanick <[email protected]> (cherry picked from commit d63162cff0e0922fc3c2ef5dfd4402004caf141e) --- src/compiler/nir/nir_repair_ssa.c | 79 ++++++++++++++++++++++----------------- 1 file changed, 44 insertions(+), 35 deletions(-) diff --git a/src/compiler/nir/nir_repair_ssa.c b/src/compiler/nir/nir_repair_ssa.c index 757afff490d..8eceadcebb0 100644 --- a/src/compiler/nir/nir_repair_ssa.c +++ b/src/compiler/nir/nir_repair_ssa.c @@ -103,48 +103,57 @@ repair_ssa_def(nir_ssa_def *def, void *void_state) nir_foreach_use_safe(src, def) { nir_block *src_block = get_src_block(src); - if (nir_block_is_unreachable(src_block) || - !nir_block_dominates(def->parent_instr->block, src_block)) { - nir_ssa_def *block_def = - nir_phi_builder_value_get_block_def(val, src_block); - - /* If def was a deref and the use we're looking at is a deref that - * isn't a cast, we need to wrap it in a cast so we don't loose any - * deref information. - */ - if (def->parent_instr->type == nir_instr_type_deref && - src->parent_instr->type == nir_instr_type_deref && - nir_instr_as_deref(src->parent_instr)->deref_type != nir_deref_type_cast) { - nir_deref_instr *cast = - nir_deref_instr_create(state->impl->function->shader, - nir_deref_type_cast); - - nir_deref_instr *deref = nir_instr_as_deref(def->parent_instr); - cast->mode = deref->mode; - cast->type = deref->type; - cast->parent = nir_src_for_ssa(block_def); - cast->cast.ptr_stride = nir_deref_instr_ptr_as_array_stride(deref); - - nir_ssa_dest_init(&cast->instr, &cast->dest, - def->num_components, def->bit_size, NULL); - nir_instr_insert(nir_before_instr(src->parent_instr), - &cast->instr); - block_def = &cast->dest.ssa; - } - - nir_instr_rewrite_src(src->parent_instr, src, - nir_src_for_ssa(block_def)); + if (src_block == def->parent_instr->block) { + assert(nir_phi_builder_value_get_block_def(val, src_block) == def); + continue; } + + nir_ssa_def *block_def = + nir_phi_builder_value_get_block_def(val, src_block); + if (block_def == def) + continue; + + /* If def was a deref and the use we're looking at is a deref that + * isn't a cast, we need to wrap it in a cast so we don't loose any + * deref information. + */ + if (def->parent_instr->type == nir_instr_type_deref && + src->parent_instr->type == nir_instr_type_deref && + nir_instr_as_deref(src->parent_instr)->deref_type != nir_deref_type_cast) { + nir_deref_instr *cast = + nir_deref_instr_create(state->impl->function->shader, + nir_deref_type_cast); + + nir_deref_instr *deref = nir_instr_as_deref(def->parent_instr); + cast->mode = deref->mode; + cast->type = deref->type; + cast->parent = nir_src_for_ssa(block_def); + cast->cast.ptr_stride = nir_deref_instr_ptr_as_array_stride(deref); + + nir_ssa_dest_init(&cast->instr, &cast->dest, + def->num_components, def->bit_size, NULL); + nir_instr_insert(nir_before_instr(src->parent_instr), + &cast->instr); + block_def = &cast->dest.ssa; + } + + nir_instr_rewrite_src(src->parent_instr, src, nir_src_for_ssa(block_def)); } nir_foreach_if_use_safe(src, def) { nir_block *block_before_if = nir_cf_node_as_block(nir_cf_node_prev(&src->parent_if->cf_node)); - if (nir_block_is_unreachable(block_before_if) || - !nir_block_dominates(def->parent_instr->block, block_before_if)) { - nir_if_rewrite_condition(src->parent_if, nir_src_for_ssa( - nir_phi_builder_value_get_block_def(val, block_before_if))); + if (block_before_if == def->parent_instr->block) { + assert(nir_phi_builder_value_get_block_def(val, block_before_if) == def); + continue; } + + nir_ssa_def *block_def = + nir_phi_builder_value_get_block_def(val, block_before_if); + if (block_def == def) + continue; + + nir_if_rewrite_condition(src->parent_if, nir_src_for_ssa(block_def)); } return true; _______________________________________________ mesa-commit mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-commit
