From 8fdac08b4d5f65973164a476bd255533ed97a766 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Mon, 4 Mar 2024 13:28:34 +0100 Subject: tree-optimization/114197 - unexpected if-conversion for vectorization The following avoids lowering a volatile bitfiled access and in case the if-converted and original loops end up in different outer loops because of simplifcations enabled scrap the result since that is not how the vectorizer expects the loops to be laid out. PR tree-optimization/114197 * tree-if-conv.cc (bitfields_to_lower_p): Do not lower if there are volatile bitfield accesses. (pass_if_conversion::execute): Throw away result if the if-converted and original loops are not nested as expected. * gcc.dg/torture/pr114197.c: New testcase. --- gcc/tree-if-conv.cc | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) (limited to 'gcc/tree-if-conv.cc') diff --git a/gcc/tree-if-conv.cc b/gcc/tree-if-conv.cc index db0d0f4..09d99fb 100644 --- a/gcc/tree-if-conv.cc +++ b/gcc/tree-if-conv.cc @@ -3701,6 +3701,14 @@ bitfields_to_lower_p (class loop *loop, if (dump_file && (dump_flags & TDF_DETAILS)) print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); + if (TREE_THIS_VOLATILE (op)) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "\t Bitfield NO OK to lower," + " the access is volatile.\n"); + return false; + } + if (!INTEGRAL_TYPE_P (TREE_TYPE (op))) { if (dump_file && (dump_flags & TDF_DETAILS)) @@ -4031,20 +4039,27 @@ pass_if_conversion::execute (function *fun) if (todo & TODO_update_ssa_any) update_ssa (todo & TODO_update_ssa_any); - /* If if-conversion elided the loop fall back to the original one. */ + /* If if-conversion elided the loop fall back to the original one. Likewise + if the loops are not nested in the same outer loop. */ for (unsigned i = 0; i < preds.length (); ++i) { gimple *g = preds[i]; if (!gimple_bb (g)) continue; - unsigned ifcvt_loop = tree_to_uhwi (gimple_call_arg (g, 0)); - unsigned orig_loop = tree_to_uhwi (gimple_call_arg (g, 1)); - if (!get_loop (fun, ifcvt_loop) || !get_loop (fun, orig_loop)) + auto ifcvt_loop = get_loop (fun, tree_to_uhwi (gimple_call_arg (g, 0))); + auto orig_loop = get_loop (fun, tree_to_uhwi (gimple_call_arg (g, 1))); + if (!ifcvt_loop || !orig_loop) { if (dump_file) fprintf (dump_file, "If-converted loop vanished\n"); fold_loop_internal_call (g, boolean_false_node); } + else if (loop_outer (ifcvt_loop) != loop_outer (orig_loop)) + { + if (dump_file) + fprintf (dump_file, "If-converted loop in different outer loop\n"); + fold_loop_internal_call (g, boolean_false_node); + } } return 0; -- cgit v1.1