[COMMITTED] Fix store merging tests on Arm

[Wilco Dijkstra]

Fix the failing store merging test on Arm.  Aligning variables fixes a
few cases, otherwise disable the test on Arm.  All store merging tests
now pass.  Committed as obvious.

ChangeLog:
2019-07-03  Wilco Dijkstra  <wdijkstr@arm.com>

testsuite/
	* gcc.dg/store_merging_27.c: Fix test for Arm.
	* gcc.dg/store_merging_28.c: Likewise.
	* gcc.dg/store_merging_29.c: Likewise.
	* gcc.dg/tree-ssa/dump-6.c: Likewise.
--

diff --git a/gcc/testsuite/gcc.dg/store_merging_27.c b/gcc/testsuite/gcc.dg/store_merging_27.c
index a691368ad3f8bad263569378421e699a9c9e8880..d3cd117bdc63442bc0ea4377365f2f83f93af143 100644
--- a/gcc/testsuite/gcc.dg/store_merging_27.c
+++ b/gcc/testsuite/gcc.dg/store_merging_27.c
@@ -18,7 +18,7 @@ bar (struct S *x)
 int
 main ()
 {
-  struct S s = {};
+  __attribute__((aligned(8))) struct S s = {};
   s.buf[1] = 1;
   s.buf[3] = 2;
   bar (&s);
diff --git a/gcc/testsuite/gcc.dg/store_merging_28.c b/gcc/testsuite/gcc.dg/store_merging_28.c
index 95a082288d73a904d72090fd1cc22d3f027ad23c..2d6cffc46945596566aa4e529b0935df6c33b786 100644
--- a/gcc/testsuite/gcc.dg/store_merging_28.c
+++ b/gcc/testsuite/gcc.dg/store_merging_28.c
@@ -3,7 +3,7 @@
 /* { dg-require-effective-target store_merge } */
 /* { dg-options "-O2 -fno-ipa-icf -fdump-tree-store-merging-details" } */
 /* { dg-final { scan-tree-dump-times "New sequence of \[24] stores to replace old one of 16 stores" 8 "store-merging" { target { i?86-*-* x86_64-*-* } } } } */
-/* { dg-final { scan-tree-dump-times "New sequence of \[24] stores to replace old one of 6 stores" 1 "store-merging" } } */
+/* { dg-final { scan-tree-dump-times "New sequence of \[24] stores to replace old one of 6 stores" 1 "store-merging" { target { ! arm*-*-* } } } } */
 
 typedef struct S { char data[16]; } S;
 void optimize_me (S);
diff --git a/gcc/testsuite/gcc.dg/store_merging_29.c b/gcc/testsuite/gcc.dg/store_merging_29.c
index 777020fab5a12946e0bc68785394347ae06060ee..6b32aa9b6f973b8ce6daec34870d37f0fe92622d 100644
--- a/gcc/testsuite/gcc.dg/store_merging_29.c
+++ b/gcc/testsuite/gcc.dg/store_merging_29.c
@@ -3,7 +3,7 @@
 /* { dg-require-effective-target store_merge } */
 /* { dg-options "-O2 -fdump-tree-store-merging-details" } */
 /* { dg-final { scan-tree-dump "New sequence of 3 stores to replace old one of 6 stores" "store-merging" { target { le && { ! arm*-*-* } } } } } */
-/* { dg-final { scan-tree-dump "New sequence of \[34] stores to replace old one of 6 stores" "store-merging" { target { be || { arm*-*-* } } } } } */
+/* { dg-final { scan-tree-dump "New sequence of \[34] stores to replace old one of 6 stores" "store-merging" { target { be && { ! arm*-*-* } } } } } */
 
 struct T { char a[1024]; };
 
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/dump-6.c b/gcc/testsuite/gcc.dg/tree-ssa/dump-6.c
index 3e09668ddc96320e3a1b964a9e60e7c5ba593460..70659c00c0efde5548fa69d4acd234bfde94791a 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/dump-6.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/dump-6.c
@@ -5,7 +5,7 @@
    { dg-require-effective-target store_merge } */
 
 
-extern char a2[2];
+extern __attribute__((aligned(2))) char a2[2];
 
 void f2 (void)
 {
@@ -13,7 +13,7 @@ void f2 (void)
   a2[1] = 0;
 }
 
-extern char a4[4];
+extern __attribute__((aligned(4))) char a4[4];
 
 void f4 (void)
 {
@@ -23,7 +23,7 @@ void f4 (void)
   a4[3] = 0;
 }
 
-extern char a8[8];
+extern __attribute__((aligned(8))) char a8[8];
 
 void f8 (void)
 {