On Wed, 20 Jun 2018, Jakub Jelinek wrote:
> 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?
OK. Looks also broken on older branches so please adjust the PR to
make sure we consider backporting.
Thanks,
Richard.
> 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
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
