[Bug middle-end/40223] New: cgraph_estimate_size_after_inlining missmatch

[Bug middle-end/40223] New: cgraph_estimate_size_after_inlining missmatch

[sergei_lus at yahoo dot com]

It is not so much a bug report, but probably a note:

In ipa-inline.c function cgraph_estimate_size_after_inlining has the following
loop:

  for (arg = DECL_ARGUMENTS (fndecl); arg; arg = TREE_CHAIN (arg))
    call_insns += estimate_move_cost (TREE_TYPE (arg));

Should it actually be something like this: 

  for (arg = DECL_ARGUMENTS (fndecl); arg; arg = TREE_CHAIN (arg))
   if (!VOID_TYPE_P (TREE_TYPE (arg)))
    call_insns += estimate_move_cost (TREE_TYPE (arg));

fndecl usually has VOID as last tree chain member, and that adds 4 points to
cost that it is probably not intending. 
See tree-inline.c on trunk (147575)estimate_num_insns:

        /* Our cost must be kept in sync with
           cgraph_estimate_size_after_inlining that does use function
           declaration to figure out the arguments.  */
        if (decl && DECL_ARGUMENTS (decl))
          {
            tree arg;
            for (arg = DECL_ARGUMENTS (decl); arg; arg = TREE_CHAIN (arg))
              if (!VOID_TYPE_P (TREE_TYPE (arg)))
                cost += estimate_move_cost (TREE_TYPE (arg));
          }
...

  My code did trigger gcc_assert (size >= 0); in
cgraph_estimate_size_after_inlining which I believe might be related to the
above described.


-- 
           Summary: cgraph_estimate_size_after_inlining missmatch
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sergei_lus at yahoo dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40223

[Bug middle-end/40223] cgraph_estimate_size_after_inlining missmatch

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2009-05-22 18:23 -------
Indeed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hubicka at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40223

[Bug middle-end/40223] cgraph_estimate_size_after_inlining missmatch

[hubicka at gcc dot gnu dot org]

------- Comment #2 from hubicka at gcc dot gnu dot org  2009-06-08 15:54 -------
The loops should be in sync, but I am but confused here.

I originally added the code only when walking types, not actual declarations,
since in decls we don't use that VOIDtype terminator.  There was some side case
where declaration actually had VOID argument in C++, but I don't recall the
exact scenario.

There is gcc_assert (!VOID_TYPE_P (type)) in estimate_move_cost I would expect
to fire if we was ever compiling function having VOID in the parm list.

How did you fire the >= 0 assert?

Honza


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40223