@@ -5633,6 +5633,19 @@ cheaper_cost_pair (struct cost_pair *a, struct cost_pair *b)
return false;
}
+/* Compare if A is a more expensive cost pair than B. Return 1, 0 and -1
+ for more expensive, equal and cheaper respectively. */
+
+static int
+compare_cost_pair (struct cost_pair *a, struct cost_pair *b)
+{
+ if (cheaper_cost_pair (a, b))
+ return -1;
+ if (cheaper_cost_pair (b, a))
+ return 1;
+
+ return 0;
+}
/* Returns candidate by that USE is expressed in IVS. */
@@ -5818,13 +5831,14 @@ iv_ca_cost (struct iv_ca *ivs)
return ivs->cost;
}
-/* Returns true if applying NEW_CP to GROUP for IVS introduces more
- invariants than OLD_CP. */
+/* Compare if applying NEW_CP to GROUP for IVS introduces more invariants
+ than OLD_CP. Return 1, 0 and -1 for more, equal and fewer invariants
+ respectively. */
-static bool
-iv_ca_more_deps (struct ivopts_data *data, struct iv_ca *ivs,
- struct iv_group *group, struct cost_pair *old_cp,
- struct cost_pair *new_cp)
+static int
+iv_ca_compare_deps (struct ivopts_data *data, struct iv_ca *ivs,
+ struct iv_group *group, struct cost_pair *old_cp,
+ struct cost_pair *new_cp)
{
gcc_assert (old_cp && new_cp && old_cp != new_cp);
unsigned old_n_invs = ivs->n_invs;
@@ -5832,7 +5846,7 @@ iv_ca_more_deps (struct ivopts_data *data, struct iv_ca *ivs,
unsigned new_n_invs = ivs->n_invs;
iv_ca_set_cp (data, ivs, group, old_cp);
- return (new_n_invs > old_n_invs);
+ return new_n_invs > old_n_invs ? 1 : (new_n_invs < old_n_invs ? -1 : 0);
}
/* Creates change of expressing GROUP by NEW_CP instead of OLD_CP and chains
@@ -6064,11 +6078,18 @@ iv_ca_extend (struct ivopts_data *data, struct iv_ca *ivs,
if (!new_cp)
continue;
- if (!min_ncand && iv_ca_more_deps (data, ivs, group, old_cp, new_cp))
- continue;
+ if (!min_ncand)
+ {
+ int cmp_invs = iv_ca_compare_deps (data, ivs, group, old_cp, new_cp);
+ /* Skip if new_cp depends on more invariants. */
+ if (cmp_invs > 0)
+ continue;
- if (!min_ncand && !cheaper_cost_pair (new_cp, old_cp))
- continue;
+ int cmp_cost = compare_cost_pair (new_cp, old_cp);
+ /* Skip if new_cp is not cheaper. */
+ if (cmp_cost > 0 || (cmp_cost == 0 && cmp_invs == 0))
+ continue;
+ }
*delta = iv_ca_delta_add (group, old_cp, new_cp, *delta);
}
Hi, Currently we only allow iv_ca extension if new_cp has cheaper cost and less deps than old_cp. This is inaccurate because it's possible the overall deps is reduced even new_cp has more deps than old_cp. This happens in case that new_cp's deps are already in iv_ca. This patch allows more iv_ca extension by checking overall deps in iv_ca. Is it OK? Thanks, bin 2017-04-11 Bin Cheng <bin.cheng@arm.com> * tree-ssa-loop-ivopts.c (compare_cost_pair): New. (iv_ca_more_deps): Renamed to ... (iv_ca_compare_deps): ... this. (iv_ca_extend): Extend iv_ca if NEW_CP is cheaper than OLD_CP. From 9f45d3762e60b3c1d2de17ef3683f944be408f96 Mon Sep 17 00:00:00 2001 From: Bin Cheng <binche01@e108451-lin.cambridge.arm.com> Date: Fri, 31 Mar 2017 14:18:55 +0100 Subject: [PATCH 27/33] extend-cand-with-cheaper-deps-20170310.txt --- gcc/tree-ssa-loop-ivopts.c | 43 ++++++++++++++++++++++++++++++++----------- 1 file changed, 32 insertions(+), 11 deletions(-)