diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 128880bed03..5fc3e7def6b 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-09  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/94050 - ABI issue with alignas on armv7hl.
+	* class.c (layout_class_type): Don't replace a class's
+	CLASSTYPE_AS_BASE if their TYPE_USER_ALIGN don't match.
+
 2020-03-09  Bin Cheng  <bin.cheng@linux.alibaba.com>
 
 	* coroutines.cc (build_actor_fn): Factor out code inserting the
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index b3787f75d7b..5340799fdd3 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -6705,6 +6705,10 @@ layout_class_type (tree t, tree *virtuals_p)
 
   /* If we didn't end up needing an as-base type, don't use it.  */
   if (CLASSTYPE_AS_BASE (t) != t
+      /* If T's CLASSTYPE_AS_BASE is TYPE_USER_ALIGN, but T is not,
+	 replacing the as-base type would change CLASSTYPE_USER_ALIGN,
+	 causing us to lose the user-specified alignment as in PR94050.  */
+      && TYPE_USER_ALIGN (t) == TYPE_USER_ALIGN (CLASSTYPE_AS_BASE (t))
       && tree_int_cst_equal (TYPE_SIZE (t),
 			     TYPE_SIZE (CLASSTYPE_AS_BASE (t))))
     CLASSTYPE_AS_BASE (t) = t;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d8719a4ab03..6c0fab65420 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-03-09  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/94050 - ABI issue with alignas on armv7hl.
+	* g++.dg/abi/align3.C: New test.
+
 2020-03-09  Christophe Lyon  <christophe.lyon@linaro.org>
 
 	* gcc.target/arm/fuse-caller-save.c: Fix DejaGnu typo.
diff --git a/gcc/testsuite/g++.dg/abi/align3.C b/gcc/testsuite/g++.dg/abi/align3.C
new file mode 100644
index 00000000000..a56693a34b8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/align3.C
@@ -0,0 +1,12 @@
+// PR c++/94050 - ABI issue with alignas on armv7hl.
+// { dg-do compile { target c++11 } }
+
+struct alignas(8) Cell {};
+struct TenuredCell : public Cell {};
+struct BaseShape : public TenuredCell {
+  void *p;
+  unsigned q, r;
+  void *s;
+  __UINTPTR_TYPE__ t;
+};
+static_assert (sizeof (BaseShape) % 8 == 0, "");