[gcc r15-3824] tree-optimization/114855 - more update_ssa speedup

[Richard Biener]

https://gcc.gnu.org/g:9a795b3a5b6a0d8b4b4f38a66ab9782aabead92e

commit r15-3824-g9a795b3a5b6a0d8b4b4f38a66ab9782aabead92e
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Sep 24 12:53:11 2024 +0200

    tree-optimization/114855 - more update_ssa speedup
    
    The following tackles another source of slow bitmap operations,
    namely populating blocks_to_update.  We already have that in
    tree view around PHI insertion but also the initial population is
    slow.  There's unfortunately a conditional inbetween list view
    requirement and the bitmap API doesn't allow opportunistic
    switching but rejects tree -> tree or list -> list transitions.
    So the following patch wraps the early population in a tree view
    section with possibly one redundant tree -> list -> tree view
    transition.
    
    This cuts tree SSA incremental from 228.25s (21%) to 65.05s (7%).
    
            PR tree-optimization/114855
            * tree-into-ssa.cc (update_ssa): Use tree view for the
            initial population of blocks_to_update.

Diff:
---
 gcc/tree-into-ssa.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/gcc/tree-into-ssa.cc b/gcc/tree-into-ssa.cc
index 1cce9d628090..fc61d47ca777 100644
--- a/gcc/tree-into-ssa.cc
+++ b/gcc/tree-into-ssa.cc
@@ -3445,6 +3445,7 @@ update_ssa (unsigned update_flags)
   blocks_with_phis_to_rewrite = BITMAP_ALLOC (NULL);
   bitmap_tree_view (blocks_with_phis_to_rewrite);
   blocks_to_update = BITMAP_ALLOC (NULL);
+  bitmap_tree_view (blocks_to_update);
 
   insert_phi_p = (update_flags != TODO_update_ssa_no_phi);
 
@@ -3492,6 +3493,8 @@ update_ssa (unsigned update_flags)
 	 placement heuristics.  */
       prepare_block_for_update (start_bb, insert_phi_p);
 
+      bitmap_list_view (blocks_to_update);
+
       tree name;
 
       if (flag_checking)
@@ -3517,6 +3520,8 @@ update_ssa (unsigned update_flags)
     }
   else
     {
+      bitmap_list_view (blocks_to_update);
+
       /* Otherwise, the entry block to the region is the nearest
 	 common dominator for the blocks in BLOCKS.  */
       start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS,