On Thu, 6 Oct 2011, Jakub Jelinek wrote:
> Hi!
>
> CAST_RESTRICT based disambiguation unfortunately isn't reliable,
> e.g. to store a non-restrict pointer into a restricted field,
> we add a non-useless cast to restricted pointer in the gimplifier,
> and while we don't consider that field to have a special restrict tag
> because it is unsafe to do so, we unfortunately create it for the
> CAST_RESTRICT before that and end up with different restrict tags
> for the same thing. See the PR for more details.
>
> This patch turns off CAST_RESTRICT handling for now, in the future
> we might try to replace it by explicit CAST_RESTRICT stmts in some form,
> but need to solve problems with multiple inlined copies of the same function
> with restrict arguments or restrict variables in it and intermixed code from
> them (or similarly code from different non-overlapping source blocks).
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
> 4.6 too?
Ok for trunk. Ok for 4.6 with the tree-ssa.c change omitted -
and the stmt folding patch applied.
Thanks,
Richard.
> 2011-10-06 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/49279
> * tree-ssa-structalias.c (find_func_aliases): Don't handle
> CAST_RESTRICT.
> * tree-ssa-forwprop.c (forward_propagate_addr_expr_1): Allow
> restrict propagation.
> * tree-ssa.c (useless_type_conversion_p): Don't return false
> if TYPE_RESTRICT differs.
>
> * gcc.dg/tree-ssa/restrict-4.c: XFAIL.
> * gcc.c-torture/execute/pr49279.c: New test.
>
> --- gcc/tree-ssa-structalias.c.jj 2011-10-04 10:18:29.000000000 +0200
> +++ gcc/tree-ssa-structalias.c 2011-10-05 12:43:42.000000000 +0200
> @@ -4494,15 +4494,6 @@ find_func_aliases (gimple origt)
> && (!in_ipa_mode
> || DECL_EXTERNAL (lhsop) || TREE_PUBLIC (lhsop)))
> make_escape_constraint (rhsop);
> - /* If this is a conversion of a non-restrict pointer to a
> - restrict pointer track it with a new heapvar. */
> - else if (gimple_assign_cast_p (t)
> - && POINTER_TYPE_P (TREE_TYPE (rhsop))
> - && POINTER_TYPE_P (TREE_TYPE (lhsop))
> - && !TYPE_RESTRICT (TREE_TYPE (rhsop))
> - && TYPE_RESTRICT (TREE_TYPE (lhsop)))
> - make_constraint_from_restrict (get_vi_for_tree (lhsop),
> - "CAST_RESTRICT");
> }
> /* Handle escapes through return. */
> else if (gimple_code (t) == GIMPLE_RETURN
> --- gcc/tree-ssa-forwprop.c.jj 2011-10-04 14:36:00.000000000 +0200
> +++ gcc/tree-ssa-forwprop.c 2011-10-05 12:46:32.000000000 +0200
> @@ -804,11 +804,6 @@ forward_propagate_addr_expr_1 (tree name
> && ((rhs_code == SSA_NAME && rhs == name)
> || CONVERT_EXPR_CODE_P (rhs_code)))
> {
> - /* Don't propagate restrict pointer's RHS. */
> - if (TYPE_RESTRICT (TREE_TYPE (lhs))
> - && !TYPE_RESTRICT (TREE_TYPE (name))
> - && !is_gimple_min_invariant (def_rhs))
> - return false;
> /* Only recurse if we don't deal with a single use or we cannot
> do the propagation to the current statement. In particular
> we can end up with a conversion needed for a non-invariant
> --- gcc/tree-ssa.c.jj 2011-09-15 12:18:54.000000000 +0200
> +++ gcc/tree-ssa.c 2011-10-05 12:44:52.000000000 +0200
> @@ -1270,12 +1270,6 @@ useless_type_conversion_p (tree outer_ty
> != TYPE_ADDR_SPACE (TREE_TYPE (inner_type)))
> return false;
>
> - /* Do not lose casts to restrict qualified pointers. */
> - if ((TYPE_RESTRICT (outer_type)
> - != TYPE_RESTRICT (inner_type))
> - && TYPE_RESTRICT (outer_type))
> - return false;
> -
> /* If the outer type is (void *), the conversion is not necessary. */
> if (VOID_TYPE_P (TREE_TYPE (outer_type)))
> return true;
> --- gcc/testsuite/gcc.dg/tree-ssa/restrict-4.c.jj 2011-10-04
> 14:33:08.000000000 +0200
> +++ gcc/testsuite/gcc.dg/tree-ssa/restrict-4.c 2011-10-05
> 16:22:33.232433231 +0200
> @@ -22,5 +22,5 @@ bar (int *x, int y)
> return p1[y];
> }
>
> -/* { dg-final { scan-tree-dump-times "return 1;" 2 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times "return 1;" 2 "optimized" { xfail *-*-*
> } } } */
> /* { dg-final { cleanup-tree-dump "optimized" } } */
> --- gcc/testsuite/gcc.c-torture/execute/pr49279.c.jj 2011-10-05
> 13:32:43.087670846 +0200
> +++ gcc/testsuite/gcc.c-torture/execute/pr49279.c 2011-10-05
> 13:32:43.087670846 +0200
> @@ -0,0 +1,35 @@
> +/* PR tree-optimization/49279 */
> +extern void abort (void);
> +
> +struct S { int a; int *__restrict p; };
> +
> +__attribute__((noinline, noclone))
> +struct S *bar (struct S *p)
> +{
> + struct S *r;
> + asm volatile ("" : "=r" (r) : "0" (p) : "memory");
> + return r;
> +}
> +
> +__attribute__((noinline, noclone))
> +int
> +foo (int *p, int *q)
> +{
> + struct S s, *t;
> + s.a = 1;
> + s.p = p;
> + t = bar (&s);
> + t->p = q;
> + s.p[0] = 0;
> + t->p[0] = 1;
> + return s.p[0];
> +}
> +
> +int
> +main ()
> +{
> + int a, b;
> + if (foo (&a, &b) != 1)
> + abort ();
> + return 0;
> +}
>
> Jakub
>
>
