diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 03387cfcac0..afac97374a5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2016-12-02  Aldy Hernandez  <aldyh@redhat.com>
+
+	PR middle-end/78328
+	* gimple-ssa-warn-alloca.c (alloca_call_type): Handle
+	VR_ANTI_RANGE.
+
 2016-12-02  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
 
 	* config/s390/s390.c (s390_save_gprs_to_fprs): Fix RTL sharing
diff --git a/gcc/gimple-ssa-warn-alloca.c b/gcc/gimple-ssa-warn-alloca.c
index e75f2fa76fc..ae379f90c0c 100644
--- a/gcc/gimple-ssa-warn-alloca.c
+++ b/gcc/gimple-ssa-warn-alloca.c
@@ -339,6 +339,8 @@ alloca_call_type (gimple *stmt, bool is_vla, tree *invalid_casted_type)
 		{
 		  // Fall through.
 		}
+	      else if (range_type == VR_ANTI_RANGE)
+		return alloca_type_and_limit (ALLOCA_UNBOUNDED);
 	      else if (range_type != VR_VARYING)
 		return
 		  alloca_type_and_limit (ALLOCA_BOUND_MAYBE_LARGE, max);
diff --git a/gcc/testsuite/gcc.dg/Walloca-12.c b/gcc/testsuite/gcc.dg/Walloca-12.c
new file mode 100644
index 00000000000..5d71cda8e51
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Walloca-12.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-Walloca-larger-than=128 -O2" } */
+
+void f (void*);
+
+void g (unsigned int n)
+{
+  if (n == 7)
+    n = 11;
+  f (__builtin_alloca (n)); /* { dg-warning "unbounded use of 'alloca'" } */
+}