[PATCH] rtl-optimization: Modify loop live data with livein of loop header

[Ajit Agarwal]

Hello All:

This patch marked LOOP_DATA->live as the livein at the loop header basic
block. This is because Livein at each basic block is live in at the loop header.

Bootstrapped and regtested on powerpc64-linux-gnu.

SPEC CPU 2017 benchmarks score is better than trunk wit this
change for INT and FP benchmarks.

THanks & Regards
Ajit


rtl-optimization: Modify loop live data with livein of loop header

Livein at each basic block is live in at the loop header.
Marked LOOP_DATA->live as the livein at the loop header basic
block.

2023-11-21  Ajit Kumar Agarwal  <aagar...@linux.ibm.com>

gcc/ChangeLog:

        * loop-invariant.cc (calculate_loop_reg_pressure): Mark
        LOOP_DATA->live as the livein at the loop header basic block.
---
 gcc/loop-invariant.cc | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/gcc/loop-invariant.cc b/gcc/loop-invariant.cc
index a9b156682bc..c15e6168d5d 100644
--- a/gcc/loop-invariant.cc
+++ b/gcc/loop-invariant.cc
@@ -2169,17 +2169,18 @@ calculate_loop_reg_pressure (void)
       }
   ira_setup_eliminable_regset ();
   bitmap_initialize (&curr_regs_live, &reg_obstack);
+
+  /* Livein (loop_hdr) is live at each of the loop basic blocks.  */
+  for (auto loop : loops_list (cfun, 0))
+    if (loop->aux == NULL)
+      bitmap_ior_into (&LOOP_DATA (loop)->regs_live, DF_LR_IN (loop->header));
+
   FOR_EACH_BB_FN (bb, cfun)
     {
       curr_loop = bb->loop_father;
       if (curr_loop == current_loops->tree_root)
        continue;
 
-      for (class loop *loop = curr_loop;
-          loop != current_loops->tree_root;
-          loop = loop_outer (loop))
-       bitmap_ior_into (&LOOP_DATA (loop)->regs_live, DF_LR_IN (bb));
-
       bitmap_copy (&curr_regs_live, DF_LR_IN (bb));
       for (i = 0; i < ira_pressure_classes_num; i++)
        curr_reg_pressure[ira_pressure_classes[i]] = 0;
-- 
2.39.3