[PATCH] Fix einline ICE with EH (PR tree-optimization/64465)

[Richard Biener]

On January 5, 2015 6:37:20 PM CET, Jan Hubicka <hubicka@ucw.cz> wrote:
>> Hi!
>> 
>> The early inliner ICEs on the following testcase, because
>redirect_all_calls
>> replaces a call to a function that could throw with
>__builtin_unreachable
>> (and, note, it still has the bug that it doesn't drop the function
>> arguments), but nothing cleans up the EH stuff for that change.
>> 
>> During function versioning fixup_cfg pass is supposed to handle that,
>> during IPA inlining there is explicit call to execute_fixup_cfg, but
>during
>> early inlining there is not.
>
>I am still confused why early inliner does any redirections? It should
>not.
>Edge redirection is part of the IPA optimization machinery.

Possibly through stmt folding.

Richard.

>> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
>> ok for trunk?
>> 
>> Honza, will you take care of dropping the arguments when you redirect
>to
>> a function that takes no arguments (I believe only
>__builtin_unreachable
>> and __pure_virtual are the cases where we do that).
>
>Yep, i will try to find time for that after arriving to Calgary this
>weekend.
>There are quite few places where substitution can happen, so I need to
>check
>them curefuly.
>
>Honza
>> 
>> 2015-01-05  Jakub Jelinek  <jakub@redhat.com>
>> 
>> 	PR tree-optimization/64465
>> 	* tree-inline.c (redirect_all_calls): During inlining
>> 	clean up EH stmts and EH edges if redirect_call_stmt_to_callee
>> 	changed the stmt to a non-throwing call.
>> 
>> 	* gcc.dg/pr64465.c: New test.
>> 
>> --- gcc/tree-inline.c.jj	2015-01-05 13:07:15.186507607 +0100
>> +++ gcc/tree-inline.c	2015-01-05 15:30:33.715001491 +0100
>> @@ -2582,13 +2582,19 @@ void
>>  redirect_all_calls (copy_body_data * id, basic_block bb)
>>  {
>>    gimple_stmt_iterator si;
>> +  gimple last = last_stmt (bb);
>>    for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
>>      {
>> -      if (is_gimple_call (gsi_stmt (si)))
>> +      gimple stmt = gsi_stmt (si);
>> +      if (is_gimple_call (stmt))
>>  	{
>> -	  struct cgraph_edge *edge = id->dst_node->get_edge (gsi_stmt
>(si));
>> +	  struct cgraph_edge *edge = id->dst_node->get_edge (stmt);
>>  	  if (edge)
>> -	    edge->redirect_call_stmt_to_callee ();
>> +	    {
>> +	      edge->redirect_call_stmt_to_callee ();
>> +	      if (stmt == last && id->call_stmt && maybe_clean_eh_stmt
>(stmt))
>> +		gimple_purge_dead_eh_edges (bb);
>> +	    }
>>  	}
>>      }
>>  }
>> --- gcc/testsuite/gcc.dg/pr64465.c.jj	2015-01-05 15:06:31.369183163
>+0100
>> +++ gcc/testsuite/gcc.dg/pr64465.c	2015-01-05 15:06:31.369183163
>+0100
>> @@ -0,0 +1,22 @@
>> +/* PR tree-optimization/64465 */
>> +/* { dg-do compile } */
>> +/* { dg-options "-O2 -fexceptions" } */
>> +
>> +extern int foo (int *);
>> +extern int bar (int, int);
>> +static inline __attribute__ ((__always_inline__))
>> +int baz (int o)
>> +{
>> +  if (__builtin_constant_p (o))
>> +    return bar (o, 1);
>> +  return bar (o, 0);
>> +}
>> +
>> +void
>> +test (void)
>> +{
>> +  int s;
>> +  foo (&s);
>> +  baz (4);
>> +  baz (s);
>> +}
>> 
>> 	Jakub