[PATCH v2 1/3] ivopts: Set register pressure cost to zero if there are enough registers.

[Jovan Dmitrovic]

In function ivopts_estimate_reg_pressure, return zero if there are
enough registers available so that spilling is not necessary.

gcc/ChangeLog:

        * tree-ssa-loop-ivopts.cc (ivopts_estimate_reg_pressure):
        Return zero if there are enough registers to store new
        invariants and induction variables.

Suggested-by:  Richard Biener <richard.guent...@gmail.com>
Signed-off-by: Jovan Dmitrović <jovan.dmitro...@htecgroup.com>
Signed-off-by: Djordje Todorović <djordje.todoro...@htecgroup.com>
Signed-off-by: Chao-Ying Fu <chao-ying...@globalfoundries.com>
Signed-off-by: Radosav Krunić <radosav.kru...@htecgroup.com>
---
 gcc/tree-ssa-loop-ivopts.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/tree-ssa-loop-ivopts.cc b/gcc/tree-ssa-loop-ivopts.cc
index bbd3cfaab243..00d5031893c1 100644
--- a/gcc/tree-ssa-loop-ivopts.cc
+++ b/gcc/tree-ssa-loop-ivopts.cc
@@ -6092,7 +6092,7 @@ ivopts_estimate_reg_pressure (struct ivopts_data *data, 
unsigned n_invs,
 
   /* If we have enough registers.  */
   if (regs_needed + target_res_regs < available_regs)
-    cost = n_new;
+    cost = 0;
   /* If close to running out of registers, try to preserve them.  */
   else if (regs_needed <= available_regs)
     cost = target_reg_cost [speed] * regs_needed;
-- 
2.34.1