This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: New badness metric for inliner


> From: David Miller <davem@davemloft.net>
> Date: Tue, 06 Nov 2012 13:54:01 -0500 (EST)
> 
> > From: David Miller <davem@davemloft.net>
> > Date: Tue, 06 Nov 2012 13:26:53 -0500 (EST)
> > 
> >> From: Jan Hubicka <hubicka@ucw.cz>
> >> Date: Tue, 6 Nov 2012 19:21:46 +0100
> >> 
> >>> The problem here is really that MAX_TIME * MAX_FREQ do not fit into 32bit integer. Fixed thus.
> >>> 
> >>> 	* ipa-inline.c (compute_uninlined_call_time): Return gcov_type.
> >>> 	(compute_inlined_call_time): Watch overflows.
> >>> 	(relative_time_benefit): Compute in gcov_type.
> >> 
> >> Thanks Jan, I'll test this right now.
> > 
> > Bootstrap still fails with this change installed:
> > 
> > ../../gcc/gcc/graphite-interchange.c:645:1: internal compiler error: in relative_time_benefit, at \
> > ipa-inline.c:785
> >  }
> 
> The problem appears to be that inline_summary (edge->caller)->time
> is negative.
> 
> #1  0x010828a0 in relative_time_benefit (callee_info=0xf76fcb10, edge=0xf598a980, edge_time=3861) \
> at ../../gcc/gcc/ipa-inline.c:785
> (gdb) p callee_info->time
> $1200 = 3864
> (gdb) p edge->frequency
> $1201 = 263
> (gdb) p (callee_info->time * edge->frequency)
> $1202 = 1016232
> (gdb) p edge->caller->global.inlined_to
> $1203 = (cgraph_node *) 0x0
> (gdb) p edge->caller
> $1204 = (cgraph_node *) 0xf589ed10
> (gdb) p p inline_summary (edge->caller)->time
> No symbol "p" in current context.
> (gdb) p inline_summary (edge->caller)->time
> $1205 = -1044761

Hmm, this is obvoiusly wrong.  All the caller time computation should be capped
to MAX_TIME that should be safe from overflows.  I will dig into it tonight or
tomorrow. Sorry for the trouble.

Honza


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]