[Bug middle-end/37046] New: Inlining produces calls which gimple_call_fndecl cannot handle correctly

["jamborm at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

In the following example, the  fucntion hooray() does not get inlined,
even though it could.

#include <stdlib.h>
#include <stdio.h>


static __attribute__((always_inline)) void hooray ()
{
  printf ("hooray\n");
}

static __attribute__((always_inline)) void hiphip (void (*f)())
{
  printf ("hip hip\n");
  f ();    
}


int main (int argc, int *argv[])
{
  hiphip (hooray);
  return 0;
}

int d()
{
  hiphip (hooray);
  return 86;
}


The reasons  are I believe  a bit more  grave than the fact  that this
(mis)use of anlways_inline does not work.  When tree-inline.c produces
an inlined copy of hiphip() it remaps the destination of the call to f
in  remap_gimple_stmt()  to  call   hooray.   However,  the  new  call
statement has this form:

  call<addr_expr<function_decl>> 

which  is a  form  that gimple_call_fndecl()  cannot  cope with.   The
consequence  is  that  rebuild_cgraph_edges()  sees  a  call  with  an
unretrievable declaration and does not build a call graph edge for it.

Therefore, when early inlining  inlines hiphip into its callers, there
is no  call graph  edge for main->hooray  (or d->hooray) and  so these
call sites  are not even  considered when doing regular  inlining, let
alone always_inlining.


-- 
           Summary: Inlining produces calls which gimple_call_fndecl cannot
                    handle correctly
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: jamborm at gcc dot gnu dot org
        ReportedBy: jamborm at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37046