Hi,
The below patch adds a new effective target keyword (store_merge) for
use in the store_merging_xxx.c tests.
The tests currently require non_strict_align, but they still fail for the avr.
Eyeballing the dump, I found that the pass doesn't attempt merging as it is
unprofitable for a target like the avr which has only single byte
stores.
I figured store merging is unlikely to be profitable for targets with
smallish word sizes, and added a check_effective_target_store_merge
that combines non_strict_align and int32plus.
Is this ok for trunk?
Regards
Senthil
gcc/testsuite/ChangeLog
2016-11-03 Senthil Kumar Selvaraj <senthil_kumar.selva...@atmel.com>
* gcc.dg/store_merging_1.c: Require store_merge.
* gcc.dg/store_merging_2.c: Likewise.
* gcc.dg/store_merging_4.c: Likewise.
* gcc.dg/store_merging_5.c: Likewise.
* gcc.dg/store_merging_6.c: Likewise.
* gcc.dg/store_merging_7.c: Likewise.
* gcc.dg/store_merging_8.c: Likewise.
* lib/target-supports.exp (check_effective_target_store_merge): New.
Index: gcc/testsuite/gcc.dg/store_merging_1.c
===================================================================
--- gcc/testsuite/gcc.dg/store_merging_1.c (revision 241808)
+++ gcc/testsuite/gcc.dg/store_merging_1.c (working copy)
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-require-effective-target non_strict_align } */
+/* { dg-require-effective-target store_merge } */
/* { dg-options "-O2 -fdump-tree-store-merging" } */
struct bar {
Index: gcc/testsuite/gcc.dg/store_merging_2.c
===================================================================
--- gcc/testsuite/gcc.dg/store_merging_2.c (revision 241808)
+++ gcc/testsuite/gcc.dg/store_merging_2.c (working copy)
@@ -1,5 +1,5 @@
/* { dg-do run } */
-/* { dg-require-effective-target non_strict_align } */
+/* { dg-require-effective-target store_merge } */
/* { dg-options "-O2 -fdump-tree-store-merging" } */
struct bar
Index: gcc/testsuite/gcc.dg/store_merging_4.c
===================================================================
--- gcc/testsuite/gcc.dg/store_merging_4.c (revision 241808)
+++ gcc/testsuite/gcc.dg/store_merging_4.c (working copy)
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-require-effective-target non_strict_align } */
+/* { dg-require-effective-target store_merge } */
/* { dg-options "-O2 -fdump-tree-store-merging" } */
/* Check that we can merge interleaving stores that are guaranteed
Index: gcc/testsuite/gcc.dg/store_merging_5.c
===================================================================
--- gcc/testsuite/gcc.dg/store_merging_5.c (revision 241808)
+++ gcc/testsuite/gcc.dg/store_merging_5.c (working copy)
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-require-effective-target non_strict_align } */
+/* { dg-require-effective-target store_merge } */
/* { dg-options "-O2 -fdump-tree-store-merging" } */
/* Make sure that non-aliasing non-constant interspersed stores do not
Index: gcc/testsuite/gcc.dg/store_merging_6.c
===================================================================
--- gcc/testsuite/gcc.dg/store_merging_6.c (revision 241808)
+++ gcc/testsuite/gcc.dg/store_merging_6.c (working copy)
@@ -1,5 +1,5 @@
/* { dg-do run } */
-/* { dg-require-effective-target non_strict_align } */
+/* { dg-require-effective-target store_merge } */
/* { dg-options "-O2 -fdump-tree-store-merging" } */
/* Check that we can widen accesses to bitfields. */
Index: gcc/testsuite/gcc.dg/store_merging_7.c
===================================================================
--- gcc/testsuite/gcc.dg/store_merging_7.c (revision 241808)
+++ gcc/testsuite/gcc.dg/store_merging_7.c (working copy)
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-require-effective-target non_strict_align } */
+/* { dg-require-effective-target store_merge } */
/* { dg-options "-O2 -fdump-tree-store-merging" } */
/* Check that we can merge consecutive array members through the pointer.
Index: gcc/testsuite/gcc.dg/store_merging_8.c
===================================================================
--- gcc/testsuite/gcc.dg/store_merging_8.c (revision 241808)
+++ gcc/testsuite/gcc.dg/store_merging_8.c (working copy)
@@ -1,5 +1,5 @@
/* { dg-do compile } */
-/* { dg-require-effective-target non_strict_align } */
+/* { dg-require-effective-target store_merge } */
/* { dg-options "-O2 -fdump-tree-store-merging" } */
struct baz {
Index: gcc/testsuite/lib/target-supports.exp
===================================================================
--- gcc/testsuite/lib/target-supports.exp (revision 241808)
+++ gcc/testsuite/lib/target-supports.exp (working copy)
@@ -8107,3 +8107,16 @@
return [check_effective_target_divmod]
}
+
+# Return 1 if store merging optimization is applicable for target.
+# Store merging is not profitable for targets like the avr which
+# can load/store only one byte at a time. Use int size as a proxy
+# for the number of bytes the target can write, and skip for targets
+# with a smallish (< 32) size.
+
+proc check_effective_target_store_merge { } {
+ if { [is-effective-target non_strict_align ] && [is-effective-target
int32plus] } {
+ return 1
+ }
+ return 0
+}
