Re: [PATCH] Fix call-cdce (PR tree-optimization/37353)

["Richard Guenther" <richard dot guenther at gmail dot com>]

On Tue, Sep 9, 2008 at 11:56 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> The testcase below ICEs, because tree-call-cdce.c VEC_alloc a 64 entry
> vector and then VEC_quick_pushes all the call-cdce candidate GIMPLE_CALLs
> into it, which obviously breaks if there are more than 64 such calls.
>
> While it could be fixed just by using VEC_safe_push instead of
> VEC_quick_push, while touching it I took the liberty to do a few cleanups as
> well - I see no reason why we need to use a global variable for the vector,
> and we can/should IMHO in the common case when there are no such calls in
> the whole function save a heap VEC_alloc/VEC_free.
>
> Bootstrapped/regtested on x86_64-linux, ok for trunk?

Ok.

Thanks,
Richard.

> 2008-09-09  Jakub Jelinek  <jakub@redhat.com>
>
>        PR tree-optimization/37353
>        * tree-call-cdce.c (cond_dead_built_in_calls): Remove.
>        (shrink_wrap_conditional_dead_built_in_calls): Add calls argument, use
>        calls instead of cond_dead_built_in_calls.
>        (tree_call_cdce): Add cond_dead_built_in_calls automatic variable,
>        initalize the vector only before adding first entry.  Use VEC_safe_push
>        instead of VEC_quick_push.  Pass cond_dead_built_in_calls to
>        shrink_wrap_conditional_dead_built_in_calls call.
>
>        * gcc.dg/pr37353.c: New test.
>
> --- gcc/tree-call-cdce.c.jj     2008-09-05 12:56:32.000000000 +0200
> +++ gcc/tree-call-cdce.c        2008-09-09 21:50:23.000000000 +0200
> @@ -99,8 +99,6 @@ typedef struct input_domain
>   bool is_ub_inclusive;
>  } inp_domain;
>
> -static VEC (gimple, heap) *cond_dead_built_in_calls;
> -
>  /* A helper function to construct and return an input
>    domain object.  LB is the lower bound, HAS_LB is
>    a boolean flag indicating if the lower bound exists,
> @@ -844,18 +842,18 @@ shrink_wrap_one_built_in_call (gimple bi
>    wrapping transformation.  */
>
>  static bool
> -shrink_wrap_conditional_dead_built_in_calls (void)
> +shrink_wrap_conditional_dead_built_in_calls (VEC (gimple, heap) *calls)
>  {
>   bool changed = false;
>   unsigned i = 0;
>
> -  unsigned n = VEC_length (gimple, cond_dead_built_in_calls);
> +  unsigned n = VEC_length (gimple, calls);
>   if (n == 0)
>     return false;
>
>   for (; i < n ; i++)
>     {
> -      gimple bi_call = VEC_index (gimple, cond_dead_built_in_calls, i);
> +      gimple bi_call = VEC_index (gimple, calls, i);
>       changed |= shrink_wrap_one_built_in_call (bi_call);
>     }
>
> @@ -870,8 +868,7 @@ tree_call_cdce (void)
>   basic_block bb;
>   gimple_stmt_iterator i;
>   bool something_changed = false;
> -  cond_dead_built_in_calls = VEC_alloc (gimple, heap, 64);
> -
> +  VEC (gimple, heap) *cond_dead_built_in_calls = NULL;
>   FOR_EACH_BB (bb)
>     {
>       /* Collect dead call candidates.  */
> @@ -887,12 +884,18 @@ tree_call_cdce (void)
>                   print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
>                   fprintf (dump_file, "\n");
>                 }
> -              VEC_quick_push (gimple, cond_dead_built_in_calls, stmt);
> +             if (cond_dead_built_in_calls == NULL)
> +               cond_dead_built_in_calls = VEC_alloc (gimple, heap, 64);
> +             VEC_safe_push (gimple, heap, cond_dead_built_in_calls, stmt);
>             }
>        }
>     }
>
> -  something_changed = shrink_wrap_conditional_dead_built_in_calls ();
> +  if (cond_dead_built_in_calls == NULL)
> +    return 0;
> +
> +  something_changed
> +    = shrink_wrap_conditional_dead_built_in_calls (cond_dead_built_in_calls);
>
>   VEC_free (gimple, heap, cond_dead_built_in_calls);
>
> --- gcc/testsuite/gcc.dg/pr37353.c.jj   2008-09-09 21:32:16.000000000 +0200
> +++ gcc/testsuite/gcc.dg/pr37353.c      2008-09-09 21:31:59.000000000 +0200
> @@ -0,0 +1,15 @@
> +/* PR tree-optimization/37353 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +
> +extern double exp (double);
> +
> +#define A exp (arg);
> +#define B A A A A A A A A A A
> +#define C B B B B B B B B B B
> +
> +void
> +foo (double arg)
> +{
> +  C
> +}
>
>        Jakub
>