Re: [PATCH] PR64979: S/390: Fix setup of overflow area pointer in va_start

[Richard Biener <richard dot guenther at gmail dot com>]

On Mon, Feb 9, 2015 at 1:17 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Mon, Feb 09, 2015 at 01:05:23PM +0100, Jakub Jelinek wrote:
>> As you can see, the updated testcase fails even on x86_64-linux.
>
> Here is an updated patch that succeeds even on i686-linux.

Ok if it fixes s390.

Thanks,
Richard.

> 2015-02-09  Jakub Jelinek  <jakub@redhat.com>
>
>         PR target/64979
>         * tree-stdarg.c (pass_stdarg::execute): Scan phi node args for
>         va_list escapes.
>
>         * gcc.dg/tree-ssa/stdarg-7.c: New test.
>         * gcc.c-torture/execute/pr64979.c: New test.
>
> --- gcc/tree-stdarg.c.jj        2015-01-09 21:59:44.000000000 +0100
> +++ gcc/tree-stdarg.c   2015-02-09 13:14:43.880406573 +0100
> @@ -856,22 +856,23 @@ pass_stdarg::execute (function *fun)
>        /* For va_list_simple_ptr, we have to check PHI nodes too.  We treat
>          them as assignments for the purpose of escape analysis.  This is
>          not needed for non-simple va_list because virtual phis don't perform
> -        any real data movement.  */
> -      if (va_list_simple_ptr)
> +        any real data movement.  Also, check PHI nodes for taking address of
> +        the va_list vars.  */
> +      tree lhs, rhs;
> +      use_operand_p uop;
> +      ssa_op_iter soi;
> +
> +      for (gphi_iterator i = gsi_start_phis (bb); !gsi_end_p (i);
> +          gsi_next (&i))
>         {
> -         tree lhs, rhs;
> -         use_operand_p uop;
> -         ssa_op_iter soi;
> +         gphi *phi = i.phi ();
> +         lhs = PHI_RESULT (phi);
>
> -         for (gphi_iterator i = gsi_start_phis (bb); !gsi_end_p (i);
> -              gsi_next (&i))
> -           {
> -             gphi *phi = i.phi ();
> -             lhs = PHI_RESULT (phi);
> -
> -             if (virtual_operand_p (lhs))
> -               continue;
> +         if (virtual_operand_p (lhs))
> +           continue;
>
> +         if (va_list_simple_ptr)
> +           {
>               FOR_EACH_PHI_ARG (uop, phi, soi, SSA_OP_USE)
>                 {
>                   rhs = USE_FROM_PTR (uop);
> @@ -894,6 +895,22 @@ pass_stdarg::execute (function *fun)
>                     }
>                 }
>             }
> +
> +         for (unsigned j = 0; !va_list_escapes
> +                              && j < gimple_phi_num_args (phi); ++j)
> +           if ((!va_list_simple_ptr
> +                || TREE_CODE (gimple_phi_arg_def (phi, j)) != SSA_NAME)
> +               && walk_tree (gimple_phi_arg_def_ptr (phi, j),
> +                             find_va_list_reference, &wi, NULL))
> +             {
> +               if (dump_file && (dump_flags & TDF_DETAILS))
> +                 {
> +                   fputs ("va_list escapes in ", dump_file);
> +                   print_gimple_stmt (dump_file, phi, 0, dump_flags);
> +                   fputc ('\n', dump_file);
> +                 }
> +               va_list_escapes = true;
> +             }
>         }
>
>        for (gimple_stmt_iterator i = gsi_start_bb (bb);
> @@ -916,8 +933,8 @@ pass_stdarg::execute (function *fun)
>
>           if (is_gimple_assign (stmt))
>             {
> -             tree lhs = gimple_assign_lhs (stmt);
> -             tree rhs = gimple_assign_rhs1 (stmt);
> +             lhs = gimple_assign_lhs (stmt);
> +             rhs = gimple_assign_rhs1 (stmt);
>
>               if (va_list_simple_ptr)
>                 {
> --- gcc/testsuite/gcc.dg/tree-ssa/stdarg-7.c.jj 2015-02-09 12:54:44.222284401 +0100
> +++ gcc/testsuite/gcc.dg/tree-ssa/stdarg-7.c    2015-02-09 12:58:10.406875647 +0100
> @@ -0,0 +1,22 @@
> +/* PR target/64979 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-stdarg" } */
> +
> +#include <stdarg.h>
> +
> +void bar (int x, va_list *ap);
> +
> +void
> +foo (int x, ...)
> +{
> +  va_list ap;
> +  int n;
> +
> +  va_start (ap, x);
> +  n = va_arg (ap, int);
> +  bar (x, (va_list *) ((n == 0) ? ((void *) 0) : &ap));
> +  va_end (ap);
> +}
> +
> +/* { dg-final { scan-tree-dump "foo: va_list escapes 1, needs to save all GPR units and all FPR units" "stdarg" } } */
> +/* { dg-final { cleanup-tree-dump "stdarg" } } */
> --- gcc/testsuite/gcc.c-torture/execute/pr64979.c.jj    2015-02-09 12:54:01.867984625 +0100
> +++ gcc/testsuite/gcc.c-torture/execute/pr64979.c       2015-02-09 13:08:17.458818847 +0100
> @@ -0,0 +1,36 @@
> +/* PR target/64979 */
> +
> +#include <stdarg.h>
> +
> +void __attribute__((noinline, noclone))
> +bar (int x, va_list *ap)
> +{
> +  if (ap)
> +    {
> +      int i;
> +      for (i = 0; i < 10; i++)
> +       if (i != va_arg (*ap, int))
> +         __builtin_abort ();
> +      if (va_arg (*ap, double) != 0.5)
> +       __builtin_abort ();
> +    }
> +}
> +
> +void __attribute__((noinline, noclone))
> +foo (int x, ...)
> +{
> +  va_list ap;
> +  int n;
> +
> +  va_start (ap, x);
> +  n = va_arg (ap, int);
> +  bar (x, (va_list *) ((n == 0) ? ((void *) 0) : &ap));
> +  va_end (ap);
> +}
> +
> +int
> +main ()
> +{
> +  foo (100, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0.5);
> +  return 0;
> +}
>
>
>         Jakub