Add vec::reverse.

2018-05-29  Martin Liska  <mliska@suse.cz>
	    David Malcolm  <dmalcolm@redhat.com>

	* vec.c (test_reverse): New.
	(vec_c_tests): Add new test.
	* vec.h (vl_ptr>::reverse): New function.

Co-Authored-By: David Malcolm <dmalcolm@redhat.com>

From-SVN: r260890

gcc/ChangeLog

+2018-05-29  Martin Liska  <mliska@suse.cz>
+	    David Malcolm  <dmalcolm@redhat.com>
+
+	* vec.c (test_reverse): New.
+	(vec_c_tests): Add new test.
+	* vec.h (vl_ptr>::reverse): New function.
+
 2018-05-29  Gerald Pfeifer  <gerald@pfeifer.com>
 
 	* config.gcc: Identify FreeBSD 3.x and 4.x as unsupported.

gcc/vec.c

@@ -476,6 +476,43 @@ test_qsort ()
   ASSERT_EQ (10, v.length ());
 }
 
+/* Verify that vec::reverse works correctly.  */
+
+static void
+test_reverse ()
+{
+  /* Reversing an empty vec ought to be a no-op.  */
+  {
+    auto_vec <int> v;
+    ASSERT_EQ (0, v.length ());
+    v.reverse ();
+    ASSERT_EQ (0, v.length ());
+  }
+
+  /* Verify reversing a vec with even length.  */
+  {
+    auto_vec <int> v;
+    safe_push_range (v, 0, 4);
+    v.reverse ();
+    ASSERT_EQ (3, v[0]);
+    ASSERT_EQ (2, v[1]);
+    ASSERT_EQ (1, v[2]);
+    ASSERT_EQ (0, v[3]);
+    ASSERT_EQ (4, v.length ());
+  }
+
+  /* Verify reversing a vec with odd length.  */
+  {
+    auto_vec <int> v;
+    safe_push_range (v, 0, 3);
+    v.reverse ();
+    ASSERT_EQ (2, v[0]);
+    ASSERT_EQ (1, v[1]);
+    ASSERT_EQ (0, v[2]);
+    ASSERT_EQ (3, v.length ());
+  }
+}
+
 /* Run all of the selftests within this file.  */
 
 void
@@ -492,6 +529,7 @@ vec_c_tests ()
   test_unordered_remove ();
   test_block_remove ();
   test_qsort ();
+  test_reverse ();
 }
 
 } // namespace selftest

gcc/vec.h

@@ -1389,6 +1389,7 @@ public:
   T *bsearch (const void *key, int (*compar)(const void *, const void *));
   unsigned lower_bound (T, bool (*)(const T &, const T &)) const;
   bool contains (const T &search) const;
+  void reverse (void);
 
   bool using_auto_storage () const;
 
@@ -1900,6 +1901,19 @@ vec<T, va_heap, vl_ptr>::contains (const T &search) const
   return m_vec ? m_vec->contains (search) : false;
 }
 
+/* Reverse content of the vector.  */
+
+template<typename T>
+inline void
+vec<T, va_heap, vl_ptr>::reverse (void)
+{
+  unsigned l = length ();
+  T *ptr = address ();
+
+  for (unsigned i = 0; i < l / 2; i++)
+    std::swap (ptr[i], ptr[l - i - 1]);
+}
+
 template<typename T>
 inline bool
 vec<T, va_heap, vl_ptr>::using_auto_storage () const