Function ivopts_estimate_reg_pressure is taxing candidate sets
by the number of candidates included in set. This makes for an
uneven playing field, making it very difficult for larger sets
to be chosen.
In try_improve_iv_set to candidate set another candidate is added
only if the cost improves (therefore prefering fewer candidates
per set), but having reg pressure cost factor in the number of
candidates makes a disbalance when choosing the best option.
gcc/ChangeLog:
* tree-ssa-loop-ivopts.cc (ivopts_estimate_reg_pressure):
Remove n_cands bias from reg pressure cost calculation.
Co-authored-by: Radosav Krunić <[email protected]>
Signed-off-by: Djordje Todorović <[email protected]>
Signed-off-by: Chao-Ying Fu <[email protected]>
Signed-off-by: Jovan Dmitrović <[email protected]>
Signed-off-by: Radosav Krunić <[email protected]>
---
gcc/tree-ssa-loop-ivopts.cc | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/gcc/tree-ssa-loop-ivopts.cc b/gcc/tree-ssa-loop-ivopts.cc
index 95c6dcf767ab..ef9274c4d6fb 100644
--- a/gcc/tree-ssa-loop-ivopts.cc
+++ b/gcc/tree-ssa-loop-ivopts.cc
@@ -6113,10 +6113,8 @@ ivopts_estimate_reg_pressure (struct ivopts_data *data,
unsigned n_invs,
}
/* Adjust cost of invariant register pressure in order to make
- the spilling of induction variables the most taxing.
- Finally, add the number of candidates, so that we prefer eliminating
- induction variables if possible. */
- return adjust_setup_cost(data, cost) + iv_spill_cost + n_cands;
+ the spilling of induction variables the most taxing. */
+ return adjust_setup_cost(data, cost) + iv_spill_cost;
}
/* For each size of the induction variable set determine the penalty. */
--
2.34.1
