From db8d94a0570dc1f3de10c9eb9fe6e91df804272b Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Tue, 11 Jan 2022 19:24:59 +0000 Subject: [PATCH] ira: Fix old-reload targets [PR103974] The new IRA heuristics would need more work on old-reload targets, since flattening needs to be able to undo the cost propagation. It's doable, but hardly seems worth it. This patch therefore makes all the new calls to ira_subloop_allocnos_can_differ_p return false if !ira_use_lra_p. The color_pass code that predated the new function (and that was the source of ira_subloop_allocnos_can_differ_p) continues to behave as before. It's a hack, but at least it has the advantage that the new parameter would become obviously unused if reload and (!)ira_use_lra_p were removed. The hack should therefore disappear alongside reload. gcc/ PR rtl-optimization/103974 * ira-int.h (ira_subloop_allocnos_can_differ_p): Take an extra argument, default true, that says whether old-reload targets should be excluded. * ira-color.c (color_pass): Pass false. --- gcc/ira-color.c | 3 ++- gcc/ira-int.h | 10 ++++++++-- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/gcc/ira-color.c b/gcc/ira-color.c index 36f3f4d70f3..59d978fe9b3 100644 --- a/gcc/ira-color.c +++ b/gcc/ira-color.c @@ -3664,7 +3664,8 @@ color_pass (ira_loop_tree_node_t loop_tree_node) ira_assert (bitmap_bit_p (subloop_node->all_allocnos, ALLOCNO_NUM (subloop_allocno))); if (ira_single_region_allocno_p (a, subloop_allocno) - || !ira_subloop_allocnos_can_differ_p (a, hard_regno >= 0)) + || !ira_subloop_allocnos_can_differ_p (a, hard_regno >= 0, + false)) { gcc_assert (!ALLOCNO_MIGHT_CONFLICT_WITH_PARENT_P (subloop_allocno)); diff --git a/gcc/ira-int.h b/gcc/ira-int.h index e1e68025211..e80fdeb0328 100644 --- a/gcc/ira-int.h +++ b/gcc/ira-int.h @@ -1607,10 +1607,16 @@ ira_loop_border_costs::move_between_loops_cost () const /* Return true if subloops that contain allocnos for A's register can use a different assignment from A. ALLOCATED_P is true for the case - in which allocation succeeded for A. */ + in which allocation succeeded for A. EXCLUDE_OLD_RELOAD is true if + we should always return false for non-LRA targets. (This is a hack + and should be removed along with old reload.) */ inline bool -ira_subloop_allocnos_can_differ_p (ira_allocno_t a, bool allocated_p = true) +ira_subloop_allocnos_can_differ_p (ira_allocno_t a, bool allocated_p = true, + bool exclude_old_reload = true) { + if (exclude_old_reload && !ira_use_lra_p) + return false; + auto regno = ALLOCNO_REGNO (a); if (pic_offset_table_rtx != NULL