Hi!
On the second following testcase, we call vrp_meet on [1B, 2B] and ~[0B, 1B]
and instead of computing the right ~[0B, 0B], we compute invalid ~[0B, -1B].
Similarly, on the first testcase, vrp_meet on [4, 8] and ~[2, 6] computes
~[2, 1] which is invalid and is canonicalized into VARYING, while we want
~[2, 3].
The problem is a thinko, for the new minimum we need to subtract 1 from the
vr0's minimum, but we overwrite it before that with the vr1's minimum and so
always compute ~[vr1min, vr1min-1].
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk/8.2?
2018-06-20 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/86231
* tree-vrp.c (union_ranges): For ( [ ) ] or ( )[ ] range and
anti-range don't overwrite *vr0min before using it to compute *vr0max.
* gcc.dg/tree-ssa/vrp119.c: New test.
* gcc.c-torture/execute/pr86231.c: New test.
--- gcc/tree-vrp.c.jj 2018-05-31 20:53:31.200438223 +0200
+++ gcc/tree-vrp.c 2018-06-20 09:36:55.536561840 +0200
@@ -5922,9 +5922,9 @@ union_ranges (enum value_range_type *vr0
if (TREE_CODE (*vr0min) == INTEGER_CST)
{
*vr0type = vr1type;
- *vr0min = vr1min;
*vr0max = int_const_binop (MINUS_EXPR, *vr0min,
build_int_cst (TREE_TYPE (*vr0min),
1));
+ *vr0min = vr1min;
}
else
goto give_up;
--- gcc/testsuite/gcc.dg/tree-ssa/vrp119.c.jj 2018-06-20 09:31:06.984238418
+0200
+++ gcc/testsuite/gcc.dg/tree-ssa/vrp119.c 2018-06-20 09:33:07.526350273
+0200
@@ -0,0 +1,20 @@
+/* PR tree-optimization/86231 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-vrp1" } */
+/* { dg-final { scan-tree-dump-not "link_error" "vrp1" } } */
+
+int bar (int);
+void link_error (void);
+
+int
+foo (int x, int y, int z)
+{
+ if (x < 4 || x > 8) __builtin_unreachable ();
+ if (y >= 2 && y <= 6) __builtin_unreachable ();
+ /* x is [4, 8], y is ~[2, 6], resulting range of e should be ~[2, 3]. */
+ int e = (z ? x : y);
+ bar (bar (bar (bar (bar (bar (bar (bar (bar (bar (bar (bar (e))))))))))));
+ if (e == 2 || e == 3)
+ link_error ();
+ return e;
+}
--- gcc/testsuite/gcc.c-torture/execute/pr86231.c.jj 2018-06-20
09:19:46.797601458 +0200
+++ gcc/testsuite/gcc.c-torture/execute/pr86231.c 2018-06-20
09:30:44.437217496 +0200
@@ -0,0 +1,30 @@
+/* PR tree-optimization/86231 */
+
+#define ONE ((void *) 1)
+#define TWO ((void *) 2)
+
+__attribute__((noipa)) int
+foo (void *p, int x)
+{
+ if (p == ONE) return 0;
+ if (!p)
+ p = x ? TWO : ONE;
+ return p == ONE ? 0 : 1;
+}
+
+int v[8];
+
+int
+main ()
+{
+ if (foo ((void *) 0, 0) != 0
+ || foo ((void *) 0, 1) != 1
+ || foo (ONE, 0) != 0
+ || foo (ONE, 1) != 0
+ || foo (TWO, 0) != 1
+ || foo (TWO, 1) != 1
+ || foo (&v[7], 0) != 1
+ || foo (&v[7], 1) != 1)
+ __builtin_abort ();
+ return 0;
+}
Jakub
