From 9609cff278d3ddea9f74b805b395d5c0293a126c Mon Sep 17 00:00:00 2001 From: Aldy Hernandez Date: Thu, 11 Nov 2021 11:27:07 +0100 Subject: [PATCH] Resolve entry loop condition for the edge remaining in the loop. There is a known failure for gfortran.dg/vector_subscript_1.f90. It was previously failing for all optimization levels except -Os. Getting the loop header copying right, now makes it fail for all levels :-). Co-authored-by: Richard Biener gcc/ChangeLog: * tree-ssa-loop-ch.c (entry_loop_condition_is_static): Resolve statically to the edge remaining in the loop. --- gcc/tree-ssa-loop-ch.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/gcc/tree-ssa-loop-ch.c b/gcc/tree-ssa-loop-ch.c index c7d86d751d4..af3401f112c 100644 --- a/gcc/tree-ssa-loop-ch.c +++ b/gcc/tree-ssa-loop-ch.c @@ -57,10 +57,24 @@ entry_loop_condition_is_static (class loop *l, path_range_query *query) || !irange::supports_type_p (TREE_TYPE (gimple_cond_lhs (last)))) return false; + edge true_e, false_e; + extract_true_false_edges_from_block (e->dest, &true_e, &false_e); + + /* If neither edge is the exit edge, this is not a case we'd like to + special-case. */ + if (!loop_exit_edge_p (l, true_e) && !loop_exit_edge_p (l, false_e)) + return false; + + tree desired_static_value; + if (loop_exit_edge_p (l, true_e)) + desired_static_value = boolean_false_node; + else + desired_static_value = boolean_true_node; + int_range<2> r; query->compute_ranges (e); query->range_of_stmt (r, last); - return r == int_range<2> (boolean_true_node, boolean_true_node); + return r == int_range<2> (desired_static_value, desired_static_value); } /* Check whether we should duplicate HEADER of LOOP. At most *LIMIT -- 2.31.1