Add target selectors to slp-37.c (PR87078)

This test was failing for Power 7 due to the lack of hw support
for unaligned accesses.

2018-08-28  Richard Sandiford  <richard.sandiford@arm.com>

gcc/testsuite/
	PR testsuite/87078
	* gcc.dg/vect/slp-37.c: Restrict scan tests to vect_hw_misalign.

From-SVN: r263913

gcc/testsuite/ChangeLog

+2018-08-28  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR testsuite/87078
+	* gcc.dg/vect/slp-37.c: Restrict scan tests to vect_hw_misalign.
+
 2018-08-28  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/87117

gcc/testsuite/gcc.dg/vect/slp-37.c

@@ -58,5 +58,5 @@ int main (void)
   return 0;
 }
 
-/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect"  } } */
-/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect"  } } */
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target vect_hw_misalign } } } */
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "vect" { target vect_hw_misalign } } } */