On Mon, May 7, 2012 at 2:30 PM, Jakub Jelinek <ja...@redhat.com> wrote:
> Hi!
>
> If returning an addressable result by value, the C++ FE makes
> it returned by reference, RESULT_DECL in that case is DECL_BY_REFERENCE
> REFERENCE_TYPE. VRP shouldn't in that case assume the <result> is
> VR_UNDEFINED, instead it only knows that it is nonnull.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok also for branches (where you think it fits).
Thanks,
Richard.
> 2012-05-07 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/53239
> * tree-vrp.c (get_value_range): Set VR of
> SSA_NAME_IS_DEFAULT_DEF of DECL_BY_REFERENCE RESULT_DECL
> to nonnull.
>
> * g++.dg/opt/vrp3.C: New test.
> * g++.dg/opt/vrp3-aux.cc: New file.
> * g++.dg/opt/vrp3.h: New file.
>
> --- gcc/tree-vrp.c.jj 2012-03-13 19:59:16.000000000 +0100
> +++ gcc/tree-vrp.c 2012-05-07 08:46:16.008803053 +0200
> @@ -695,17 +695,22 @@ get_value_range (const_tree var)
> /* If VAR is a default definition of a parameter, the variable can
> take any value in VAR's type. */
> sym = SSA_NAME_VAR (var);
> - if (SSA_NAME_IS_DEFAULT_DEF (var)
> - && TREE_CODE (sym) == PARM_DECL)
> + if (SSA_NAME_IS_DEFAULT_DEF (var))
> {
> - /* Try to use the "nonnull" attribute to create ~[0, 0]
> - anti-ranges for pointers. Note that this is only valid with
> - default definitions of PARM_DECLs. */
> - if (POINTER_TYPE_P (TREE_TYPE (sym))
> - && nonnull_arg_p (sym))
> + if (TREE_CODE (sym) == PARM_DECL)
> + {
> + /* Try to use the "nonnull" attribute to create ~[0, 0]
> + anti-ranges for pointers. Note that this is only valid with
> + default definitions of PARM_DECLs. */
> + if (POINTER_TYPE_P (TREE_TYPE (sym))
> + && nonnull_arg_p (sym))
> + set_value_range_to_nonnull (vr, TREE_TYPE (sym));
> + else
> + set_value_range_to_varying (vr);
> + }
> + else if (TREE_CODE (sym) == RESULT_DECL
> + && DECL_BY_REFERENCE (sym))
> set_value_range_to_nonnull (vr, TREE_TYPE (sym));
> - else
> - set_value_range_to_varying (vr);
> }
>
> return vr;
> --- gcc/testsuite/g++.dg/opt/vrp3.C.jj 2012-05-07 09:09:08.574648044 +0200
> +++ gcc/testsuite/g++.dg/opt/vrp3.C 2012-05-07 09:09:03.138678376 +0200
> @@ -0,0 +1,47 @@
> +// PR tree-optimization/53239
> +// { dg-do run }
> +// { dg-options "-O2" }
> +// { dg-additional-sources "vrp3-aux.cc" }
> +
> +#include "vrp3.h"
> +
> +struct M
> +{
> + M (R m);
> + R val;
> + static int compare (M const &, M const &);
> +};
> +
> +inline M const &
> +min (M const & t1, M const & t2)
> +{
> + return R::compare (t1.val, t2.val) < 0 ? t1 : t2;
> +}
> +
> +M::M (R m)
> +{
> + val = m;
> +}
> +
> +M
> +test (M *x)
> +{
> + M n (R (0, 0));
> +
> + for (int i = 0; i < 2; i++)
> + {
> + M p = x[i];
> + n = min (n, p);
> + }
> +
> + if (n.val.r2 != 2 || n.val.r1 != 1)
> + __builtin_abort ();
> + return n;
> +}
> +
> +int
> +main ()
> +{
> + M x[2] = { M (R (1, 2)), M (R (1, 1)) };
> + test (x);
> +}
> --- gcc/testsuite/g++.dg/opt/vrp3-aux.cc.jj 2012-05-07 09:09:22.060567366
> +0200
> +++ gcc/testsuite/g++.dg/opt/vrp3-aux.cc 2012-05-07 09:09:28.538528045
> +0200
> @@ -0,0 +1,21 @@
> +// { dg-do compile }
> +// { dg-options "" }
> +
> +#include "vrp3.h"
> +
> +R::R ()
> +{
> + r1 = r2 = 1;
> +}
> +
> +R::R (int n, int d)
> +{
> + r1 = n;
> + r2 = d;
> +}
> +
> +int
> +R::compare (R const &r, R const &s)
> +{
> + return (int) (r.r1 * s.r2 - s.r1 * r.r2);
> +}
> --- gcc/testsuite/g++.dg/opt/vrp3.h.jj 2012-05-07 09:09:41.402448593 +0200
> +++ gcc/testsuite/g++.dg/opt/vrp3.h 2012-05-07 09:09:46.509420562 +0200
> @@ -0,0 +1,9 @@
> +struct R
> +{
> + long long r1, r2;
> + void copy (R const &r) { r1 = r.r1; r2 = r.r2; }
> + R ();
> + explicit R (int, int);
> + R (R const &r) { copy (r); }
> + static int compare (R const &, R const &);
> +};
>
> Jakub
