On Sat, 2018-09-22 at 16:39 -0500, Jason Ekstrand wrote:
> If the block in which the jump is inserted is the predecessor of a
> phi
> then we need to remove phi sources otherwise the phi may end up with
> things improperly connected. Found by running the Vulkan CTS with
> SPIR-V optimizations enabled.
>
> Cc: mesa-sta...@lists.freedesktop.org
> ---
> src/compiler/nir/nir_control_flow.c | 36 +++++++++++++++----------
> ----
> 1 file changed, 19 insertions(+), 17 deletions(-)
>
> diff --git a/src/compiler/nir/nir_control_flow.c
> b/src/compiler/nir/nir_control_flow.c
> index 3b0a0f1a5b0..a82f35550b8 100644
> --- a/src/compiler/nir/nir_control_flow.c
> +++ b/src/compiler/nir/nir_control_flow.c
> @@ -437,6 +437,23 @@ nearest_loop(nir_cf_node *node)
> return nir_cf_node_as_loop(node);
> }
>
> +static void
> +remove_phi_src(nir_block *block, nir_block *pred)
> +{
> + nir_foreach_instr(instr, block) {
> + if (instr->type != nir_instr_type_phi)
> + break;
> +
> + nir_phi_instr *phi = nir_instr_as_phi(instr);
> + nir_foreach_phi_src_safe(src, phi) {
> + if (src->pred == pred) {
> + list_del(&src->src.use_link);
> + exec_node_remove(&src->node);
> + }
> + }
> + }
> +}
> +
> /*
> * update the CFG after a jump instruction has been added to the end
> of a block
> */
> @@ -447,6 +464,8 @@ nir_handle_add_jump(nir_block *block)
> nir_instr *instr = nir_block_last_instr(block);
> nir_jump_instr *jump_instr = nir_instr_as_jump(instr);
>
> + if (block->successors[0])
> + remove_phi_src(block->successors[0], block);
Don't we need to do the same for block->successors[1]?
Iago
> unlink_block_successors(block);
>
> nir_function_impl *impl = nir_cf_node_get_function(&block-
> >cf_node);
> @@ -470,23 +489,6 @@ nir_handle_add_jump(nir_block *block)
> }
> }
>
> -static void
> -remove_phi_src(nir_block *block, nir_block *pred)
> -{
> - nir_foreach_instr(instr, block) {
> - if (instr->type != nir_instr_type_phi)
> - break;
> -
> - nir_phi_instr *phi = nir_instr_as_phi(instr);
> - nir_foreach_phi_src_safe(src, phi) {
> - if (src->pred == pred) {
> - list_del(&src->src.use_link);
> - exec_node_remove(&src->node);
> - }
> - }
> - }
> -}
> -
> /* Removes the successor of a block with a jump. Note that the jump
> to be
> * eliminated may be free-floating.
> */
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