Index: gcc/config/rs6000/rs6000-protos.h
===================================================================
--- gcc/config/rs6000/rs6000-protos.h	(revision 212147)
+++ gcc/config/rs6000/rs6000-protos.h	(working copy)
@@ -155,6 +155,7 @@
 
 #ifdef TREE_CODE
 extern unsigned int rs6000_data_alignment (tree, unsigned int, enum data_align);
+extern bool rs6000_special_adjust_field_align_p (tree, unsigned int);
 extern unsigned int rs6000_special_round_type_align (tree, unsigned int,
 						     unsigned int);
 extern unsigned int darwin_rs6000_special_round_type_align (tree, unsigned int,
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c	(revision 212147)
+++ gcc/config/rs6000/rs6000.c	(working copy)
@@ -5878,6 +5878,32 @@
   return align;
 }
 
+/* Previous GCC releases forced all vector types to have 16-byte alignment.  */
+
+bool
+rs6000_special_adjust_field_align_p (tree field, unsigned int computed)
+{
+  if (TARGET_ALTIVEC && TREE_CODE (TREE_TYPE (field)) == VECTOR_TYPE)
+    {
+      if (computed != 128)
+	{
+	  static bool warned;
+	  if (!warned && warn_psabi)
+	    {
+	      warned = true;
+	      inform (input_location,
+		      "the layout of aggregates containing vectors with"
+		      " %d-byte alignment has changed in GCC 4.10",
+		      computed / BITS_PER_UNIT);
+	    }
+	}
+      /* In current GCC there is no special case.  */
+      return false;
+    }
+
+  return false;
+}
+
 /* AIX increases natural record alignment to doubleword if the first
    field is an FP double while the FP fields remain word aligned.  */
 
Index: gcc/config/rs6000/sysv4.h
===================================================================
--- gcc/config/rs6000/sysv4.h	(revision 212147)
+++ gcc/config/rs6000/sysv4.h	(working copy)
@@ -292,7 +292,7 @@
 /* An expression for the alignment of a structure field FIELD if the
    alignment computed in the usual way is COMPUTED.  */
 #define ADJUST_FIELD_ALIGN(FIELD, COMPUTED)				      \
-	((TARGET_ALTIVEC && TREE_CODE (TREE_TYPE (FIELD)) == VECTOR_TYPE)     \
+	(rs6000_special_adjust_field_align_p ((FIELD), (COMPUTED))	      \
 	 ? 128 : COMPUTED)
 
 #undef  BIGGEST_FIELD_ALIGNMENT
Index: gcc/config/rs6000/linux64.h
===================================================================
--- gcc/config/rs6000/linux64.h	(revision 212147)
+++ gcc/config/rs6000/linux64.h	(working copy)
@@ -246,7 +246,7 @@
 /* PowerPC64 Linux word-aligns FP doubles when -malign-power is given.  */
 #undef  ADJUST_FIELD_ALIGN
 #define ADJUST_FIELD_ALIGN(FIELD, COMPUTED) \
-  ((TARGET_ALTIVEC && TREE_CODE (TREE_TYPE (FIELD)) == VECTOR_TYPE)	\
+  (rs6000_special_adjust_field_align_p ((FIELD), (COMPUTED))		\
    ? 128								\
    : (TARGET_64BIT							\
       && TARGET_ALIGN_NATURAL == 0					\
Index: gcc/config/rs6000/freebsd64.h
===================================================================
--- gcc/config/rs6000/freebsd64.h	(revision 212147)
+++ gcc/config/rs6000/freebsd64.h	(working copy)
@@ -367,7 +367,7 @@
 /* PowerPC64 Linux word-aligns FP doubles when -malign-power is given.  */
 #undef  ADJUST_FIELD_ALIGN
 #define ADJUST_FIELD_ALIGN(FIELD, COMPUTED) \
-  ((TARGET_ALTIVEC && TREE_CODE (TREE_TYPE (FIELD)) == VECTOR_TYPE)     \
+  (rs6000_special_adjust_field_align_p ((FIELD), (COMPUTED))		\
    ? 128                                                                \
    : (TARGET_64BIT                                                      \
       && TARGET_ALIGN_NATURAL == 0                                      \
Index: gcc/testsuite/gcc.target/powerpc/ppc64-abi-warn-3.c
===================================================================
--- /dev/null
+++ gcc/testsuite/gcc.target/powerpc/ppc64-abi-warn-3.c	(revision 0)
@@ -0,0 +1,9 @@
+/* { dg-do compile { target { powerpc*-*-linux* && lp64 } } } */
+/* { dg-require-effective-target powerpc_altivec_ok } */
+/* { dg-options "-maltivec" } */
+
+struct test
+  {
+    int a __attribute__((vector_size (8)));
+  }; /* { dg-message "note: the layout of aggregates containing vectors with 8-byte alignment has changed" } */
+
