diff --git a/gcc/testsuite/g++.dg/vect/pr116817.cc b/gcc/testsuite/g++.dg/vect/pr116817.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7e28982fb138c2cccc4f956aedb03fa454d9d858
--- /dev/null
+++ b/gcc/testsuite/g++.dg/vect/pr116817.cc
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O3" } */
+
+int main_ulData0;
+unsigned *main_pSrcBuffer;
+int main(void) {
+  int iSrc = 0;
+  bool bData0;
+  for (; iSrc < 4; iSrc++) {
+    if (bData0)
+      main_pSrcBuffer[iSrc] = main_ulData0;
+    else
+      main_pSrcBuffer[iSrc] = 0;
+    bData0 = !bData0;
+  }
+}
diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
index e7e877dd2adb55262822f1660f8d92b42d44e6d0..b174ff1e705cec8e7bb414c760eb170ca98222cb 100644
--- a/gcc/tree-vect-patterns.cc
+++ b/gcc/tree-vect-patterns.cc
@@ -6062,12 +6062,15 @@ vect_recog_bool_pattern (vec_info *vinfo,
       if (get_vectype_for_scalar_type (vinfo, type) == NULL_TREE)
 	return NULL;
 
+      enum vect_def_type dt;
       if (check_bool_pattern (var, vinfo, bool_stmts))
 	var = adjust_bool_stmts (vinfo, bool_stmts, type, stmt_vinfo);
       else if (integer_type_for_mask (var, vinfo))
 	return NULL;
       else if (TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE
-	       && !vect_get_internal_def (vinfo, var))
+	       && vect_is_simple_use (var, vinfo, &dt)
+	       && (dt == vect_external_def
+		   || dt == vect_constant_def))
 	{
 	  /* If the condition is already a boolean then manually convert it to a
 	     mask of the given integer type but don't set a vectype.  */