This patch checks for the reordering cost on the target, for each store,
using `avoid_store_forwarding_reorder_cost_p` before applying the
transformation.
It, also, updates the x86_64 testcases to set `asf-default-cost-value=1`,
in order for the transformations to be applied.
gcc/ChangeLog:
* avoid-store-forwarding.cc (process_store_forwarding):
Call `avoid_store_forwarding_reorder_cost_p` for each store
instruction in the store-load sequence.
gcc/testsuite/ChangeLog:
* gcc.target/x86_64/abi/callabi/avoid-store-forwarding-1.c:
Add --param asf-default-cost-value=1.
* gcc.target/x86_64/abi/callabi/avoid-store-forwarding-2.c: Likewise.
Signed-off-by: Konstantinos Eleftheriou <[email protected]>
---
(no changes since v1)
gcc/avoid-store-forwarding.cc | 16 ++++++++++++++--
.../abi/callabi/avoid-store-forwarding-1.c | 2 +-
.../abi/callabi/avoid-store-forwarding-2.c | 2 +-
3 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/gcc/avoid-store-forwarding.cc b/gcc/avoid-store-forwarding.cc
index 78ed736e0a3e..c940b4ad98de 100644
--- a/gcc/avoid-store-forwarding.cc
+++ b/gcc/avoid-store-forwarding.cc
@@ -264,6 +264,17 @@ process_store_forwarding (vec<store_fwd_info> &stores,
rtx_insn *load_insn,
/* Check if we can emit bit insert instructions for all forwarded stores. */
FOR_EACH_VEC_ELT (stores, i, it)
{
+ /* First check if it's profitable for the target to rearrange the store.
+ If it's not, we can't continue with the tranformation. */
+ if (!targetm.avoid_store_forwarding_reorder_cost_p (
+ GET_MODE (it->store_mem), load_mem_mode, it->offset))
+ {
+ if (dump_file)
+ fprintf (dump_file, "Not transformed due to target decision on "
+ "the store/load reordering.\n");
+ return false;
+ }
+
it->mov_reg = gen_reg_rtx (GET_MODE (it->store_mem));
rtx_insn *insns = NULL;
@@ -351,12 +362,13 @@ process_store_forwarding (vec<store_fwd_info> &stores,
rtx_insn *load_insn,
total_cost -= insn_cost (load_insn, true);
/* Let the target decide if transforming this store forwarding instance is
- profitable. */
+ profitable based on the cost of the newly generated instructions. */
if (!targetm.avoid_store_forwarding_p (stores, load_mem, total_cost,
load_elim))
{
if (dump_file)
- fprintf (dump_file, "Not transformed due to target decision.\n");
+ fprintf (dump_file, "Not transformed due to target decision on the "
+ "cost of the generated instructions.\n");
return false;
}
diff --git
a/gcc/testsuite/gcc.target/x86_64/abi/callabi/avoid-store-forwarding-1.c
b/gcc/testsuite/gcc.target/x86_64/abi/callabi/avoid-store-forwarding-1.c
index d94bcf136ace..8005d210b5f7 100644
--- a/gcc/testsuite/gcc.target/x86_64/abi/callabi/avoid-store-forwarding-1.c
+++ b/gcc/testsuite/gcc.target/x86_64/abi/callabi/avoid-store-forwarding-1.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -favoid-store-forwarding" } */
+/* { dg-options "-O2 -favoid-store-forwarding --param
asf-default-cost-value=1" } */
typedef union {
char arr_8[8];
diff --git
a/gcc/testsuite/gcc.target/x86_64/abi/callabi/avoid-store-forwarding-2.c
b/gcc/testsuite/gcc.target/x86_64/abi/callabi/avoid-store-forwarding-2.c
index b958612173bd..36c88e27c20f 100644
--- a/gcc/testsuite/gcc.target/x86_64/abi/callabi/avoid-store-forwarding-2.c
+++ b/gcc/testsuite/gcc.target/x86_64/abi/callabi/avoid-store-forwarding-2.c
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-options "-O2 -favoid-store-forwarding
-fdump-rtl-avoid_store_forwarding" } */
+/* { dg-options "-O2 -favoid-store-forwarding
-fdump-rtl-avoid_store_forwarding --param asf-default-cost-value=1" } */
typedef union {
char arr_8[8];
--
2.50.1
