value-relation: Fix up relation_union [PR108447]

While looking at the PR, I've noticed one row in rr_union_table
is wrong.  relation_union should be commutative, but due to that
bug is not.  The following patch adds a self-test for that
property (fails without the first hunk) and fixes that line.

The actual floating point relation problem isn't fixed by this patch
though.

2023-01-19  Jakub Jelinek  <[email protected]>

	PR tree-optimization/108447
	* value-relation.cc (rr_union_table): Fix VREL_UNDEFINED row order.
	(relation_tests): Add self-tests for relation_{intersect,union}
	commutativity.
	* selftest.h (relation_tests): Declare.
	* function-tests.cc (test_ranges): Call it.

Author: jakubjelinek

gcc/function-tests.cc

@@ -583,6 +583,7 @@ test_ranges ()
   push_cfun (fun);
   range_tests ();
   range_op_tests ();
+  relation_tests ();
 
   build_cfg (fndecl);
   convert_to_ssa (fndecl);

gcc/selftest.h

@@ -244,6 +244,7 @@ extern void predict_cc_tests ();
 extern void pretty_print_cc_tests ();
 extern void range_tests ();
 extern void range_op_tests ();
+extern void relation_tests ();
 extern void gimple_range_tests ();
 extern void read_rtl_function_cc_tests ();
 extern void rtl_tests_cc_tests ();

gcc/value-relation.cc

@@ -115,7 +115,7 @@ relation_kind rr_union_table[VREL_LAST][VREL_LAST] = {
   { VREL_VARYING, VREL_VARYING, VREL_VARYING, VREL_VARYING, VREL_VARYING,
     VREL_VARYING, VREL_VARYING, VREL_VARYING },
 // VREL_UNDEFINED
-  { VREL_VARYING, VREL_LT, VREL_LE, VREL_GT, VREL_GE, VREL_UNDEFINED,
+  { VREL_VARYING, VREL_UNDEFINED, VREL_LT, VREL_LE, VREL_GT, VREL_GE,
     VREL_EQ, VREL_NE },
 // VREL_LT
   { VREL_VARYING, VREL_LT, VREL_LT, VREL_LE, VREL_NE, VREL_VARYING, VREL_LE,
@@ -1718,3 +1718,26 @@ equiv_relation_iterator::get_name (relation_kind *rel)
     }
   return NULL_TREE;
 }
+
+#if CHECKING_P
+#include "selftest.h"
+
+namespace selftest
+{
+void
+relation_tests ()
+{
+  // Verify commutativity of relation_intersect and relation_union.
+  for (relation_kind r1 = VREL_VARYING; r1 < VREL_PE8;
+       r1 = relation_kind (r1 + 1))
+    for (relation_kind r2 = VREL_VARYING; r2 < VREL_PE8;
+	 r2 = relation_kind (r2 + 1))
+      {
+	ASSERT_EQ (relation_intersect (r1, r2), relation_intersect (r2, r1));
+	ASSERT_EQ (relation_union (r1, r2), relation_union (r2, r1));
+      }
+}
+
+} // namespace selftest
+
+#endif // CHECKING_P