<div dir="ltr"><div class="gmail_quote"><div dir="ltr">On Tue, Jul 10, 2018 at 11:49 PM Timothy Arceri <<a href="mailto:tarceri@itsqueeze.com">tarceri@itsqueeze.com</a>> wrote: </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">This adds support for unrolling the classic do { // ... } while (false) that is used to wrap multi-line macros. GLSL IR also wraps switch statements in a loop like this. shader-db results IVB: total loops in shared programs: 2515 -> 2512 (-0.12%) loops in affected programs: 33 -> 30 (-9.09%) helped: 3 HURT: 0 --- src/compiler/nir/nir_opt_loop_unroll.c | 63 ++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) diff --git a/src/compiler/nir/nir_opt_loop_unroll.c b/src/compiler/nir/nir_opt_loop_unroll.c index 38901470f96..f715fc8ebda 100644 --- a/src/compiler/nir/nir_opt_loop_unroll.c +++ b/src/compiler/nir/nir_opt_loop_unroll.c @@ -516,6 +516,69 @@ process_loops(nir_shader *sh, nir_cf_node *cf_node, bool *has_nested_loop) */ if (!progress) { + /* Check for the the classic + * + * do { + * // ... + * } while (false) + * + * that is used to wrap multi-line macros. GLSL IR also wraps switch + * statements in a loop like this. + */ + if (loop->info->limiting_terminator == NULL && + list_empty(&loop->info->loop_terminator_list) && + !loop->info->complex_loop) { + </blockquote><div> </div><div>Mind putting all the code below in a "wrapper_unroll" or "trivial_unroll" helper? </div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> + nir_block *blk_after_loop = + nir_cursor_current_block(nir_after_cf_node(&loop->cf_node)); + + /* There may still be some single src phis following the loop that + * have not yet been cleaned up by another pass. Tidy those up before + * unrolling the loop. + */ + nir_foreach_instr_safe(instr, blk_after_loop) { + if (instr->type != nir_instr_type_phi) + break; + + nir_phi_instr *phi = nir_instr_as_phi(instr); + assert(exec_list_length(&phi->srcs) == 1); + + nir_phi_src *phi_src = + exec_node_data(nir_phi_src, + exec_list_get_head(&phi->srcs), + node); + + nir_ssa_def_rewrite_uses(&phi->dest.ssa, phi_src->src); + nir_instr_remove(instr); + + progress = true; + } + + nir_block *last_loop_blk = nir_loop_last_block(loop); + if (nir_block_ends_in_break(last_loop_blk)) { </blockquote><div> </div><div>This confuses me. Above, you assert that all phis have exactly one source and here you have an if (nir_block_ends_in_break(last_block)); which one is it? Either our loop terminator check above guarantees that we're in the "do { } while (true)" case where we can assume a single exit at the end of the loop or it doesn't. Which one is it? </div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> + + /* Remove break at end of the loop */ + nir_instr *break_instr = nir_block_last_instr(last_loop_blk); + nir_instr_remove(break_instr); + + /* Pluck out the loop body. */ + nir_cf_list loop_body; + nir_cf_extract(&loop_body, + nir_before_block(nir_loop_first_block(loop)), + nir_after_block(nir_loop_last_block(loop))); + + /* Reinsert loop body after the loop */ + nir_cf_reinsert(&loop_body, nir_after_cf_node(&loop->cf_node)); + + /* The loop has been unrolled so remove it. */ + nir_cf_node_remove(&loop->cf_node); + + progress = true; + } + + goto exit; + } + if (*has_nested_loop || loop->info->limiting_terminator == NULL) goto exit; -- 2.17.1 _______________________________________________ mesa-dev mailing list <a href="mailto:mesa-dev@lists.freedesktop.org" target="_blank">mesa-dev@lists.freedesktop.org</a> <a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev" rel="noreferrer" target="_blank">https://lists.freedesktop.org/mailman/listinfo/mesa-dev</a> </blockquote></div></div>