[patch] PR51347 alias problem

[Aldy Hernandez]

On 12/02/11 19:26, Patrick Marlier wrote:
> Hi,
>
> PR51347 shows up a problem due to the TM IPA rework.
> tree_function_versioning segfault because the cfg of old_decl (alias) is
> NULL.
> Indeed, an alias can get called but tm cg data are in the parent of the
> alias.
>

[Richard, this one's for you :-)].

Using the parent node for aliases (as in your patch) makes sense, but I 
don't see tree_function_versioning() segfaulting as you claim.  What I 
see is estimate_function_body_sizes() failing because it is trying to 
analyze an edge that doesn't exist here:

	  if (is_gimple_call (stmt))
	    {
	      struct cgraph_edge *edge = cgraph_edge (node, stmt);
	      struct inline_edge_summary *es = inline_edge_summary (edge);

In this particular case, STMT is an indirect call through the runtime:


   D.2511_16 = __builtin__ITM_getTMCloneOrIrrevocable (__comp_dtor );
   D.2512_17 = (void Info::<T438> (struct Info *) *) D.2511_16;
   D.2512_17 (D.2504_2);
   ^^^^^^^^^^^^^^^^^^^^^ **EDGELESS STATEMENT**

The edge in this call was removed because we couldn't find an 
appropriate static replacement:

      /* As we've already skipped pure calls and appropriate builtins,
	 and we've already marked irrevocable blocks, if we can't come
	 up with a static replacement, then ask the runtime.  */

Be that as it may, I am lost in a plethora of complete and base 
destructors, so I am hoping Richard can review your patch more thoroughly.

Aldy