Comments
Patch
===================================================================
@@ -0,0 +1,27 @@
+extern void link_error(void);
+
+#define RANGE(name, min, max) \
+ if (name < min || name > max) \
+ return;
+#define ANTI_RANGE(name, min, max) \
+ if (name >= min && name <= max) \
+ return;
+#define MERGE(cond, name1, name2) \
+ if (cond) \
+ name1 = name2;
+#define CHECK_RANGE(expr, min, max) \
+ do { \
+ __typeof__ (expr) v = (expr); \
+ if (v < min) link_error(); \
+ if (v > max) link_error(); \
+ if (v < min || v > max) link_error (); \
+ } while (0)
+#define CHECK_ANTI_RANGE(expr, min, max) \
+ do { \
+ __typeof__ (expr) v = (expr); \
+ if (v >= min) \
+ if (v <= max) \
+ link_error(); \
+ if (v >= min && v <= max) \
+ link_error(); \
+ } while (0)
===================================================================
@@ -0,0 +1,24 @@
+/* { dg-do link } */
+/* { dg-options "-O2 -fdump-tree-vrp1" } */
+
+#include "vrp.h"
+
+void test1 (int i, int j, int b)
+{
+ RANGE(i, 2, 6);
+ ANTI_RANGE(j, 1, 7);
+ MERGE(b, i, j);
+ CHECK_ANTI_RANGE(i, 7, 7);
+ CHECK_ANTI_RANGE(i, 1, 1);
+ /* If we swap the anti-range tests the ~[6, 6] test is never eliminated. */
+}
+int main() { }
+
+/* While subsequent VRP/DOM passes manage to even recognize the ~[6, 6]
+ test as redundant a single VRP run will arbitrarily choose ~[0, 0] when
+ merging [1, 5] with ~[0, 6] so the first VRP pass can only eliminate
+ the ~[0, 0] check as redundant. */
+
+/* { dg-final { scan-tree-dump-times "vrp1" 0 "link_error" { xfail *-*-* } } } */
+/* { dg-final { scan-tree-dump-times "vrp1" 1 "link_error" } } */
+/* { dg-final { cleanup-tree-dump "vrp1" } } */