RE: Typo or intended?

["Bingfeng Mei" <bmei at broadcom dot com>]

That's fine. It seems that other targets don't have such issue. Our target is too special and it is
still a private port. I can just use optimize < 1 here. Thanks,

Bingfeng 

> -----Original Message-----
> From: Vladimir Makarov [mailto:vmakarov@redhat.com] 
> Sent: 23 March 2009 19:40
> To: Bingfeng Mei
> Cc: gcc@gcc.gnu.org
> Subject: Re: Typo or intended?
> 
> Bingfeng Mei wrote:
> > Hello,
> > I just updated our porting to include last 2-3 weeks of GCC 
> developments. I noticed a large number of test failures at 
> -O1 that use a user-defined data type (based on a special 
> register file of our processor). All variables of such type 
> are now spilled to memory which we don't allow at -O1 because 
> it is too expensive. After investigation, I found that it is 
> the following new code causes the trouble. I don't quite 
> understand the function of the new code, but I don't see 
> what's special for -O1 in terms of register allocation in 
> comparison with higher optimizing levels. If I change it to 
> (optimize < 1), everthing is fine as before. I start to 
> wonder whether (optimize <= 1) is a typo or intended. Thanks 
> in advance.
> >
> >   
> Sorry for the delay with the answer.  I was on vacation last week.
> 
> As Andrew Haley guess, it was intended.  I thought that improving 
> debugging for -O1 is also important (more important than 
> optimization).  
> Although GCC manual says
> 
>      With `-O', the compiler tries to reduce code size and execution
>      time, without performing any optimizations that take a great deal
>      of compilation time.
> 
> it also says
> 
> `-O' also turns on `-fomit-frame-pointer' on machines where doing
>      so does not interfere with debugging.
> 
> Therefore I've decided to do analogous thing for the patch.  
> May be I am 
> wrong.  We could do this only for -O0 if people really want 
> this which I 
> am not sure about.
> > Cheers,
> > Bingfeng Mei
> > Broadcom UK
> >
> >       if ((! flag_caller_saves && ALLOCNO_CALLS_CROSSED_NUM 
> (a) != 0)
> > 	  /* For debugging purposes don't put user defined variables in
> > 	     callee-clobbered registers.  */
> > 	  || (optimize <= 1                               
> <---------  why include -O1? 
> > 	      && (attrs = REG_ATTRS (regno_reg_rtx 
> [ALLOCNO_REGNO (a)])) != NULL
> > 	      && (decl = attrs->decl) != NULL
> > 	      && VAR_OR_FUNCTION_DECL_P (decl)
> > 	      && ! DECL_ARTIFICIAL (decl)))
> > 	{
> > 	  IOR_HARD_REG_SET (ALLOCNO_TOTAL_CONFLICT_HARD_REGS (a),
> > 			    call_used_reg_set);
> > 	  IOR_HARD_REG_SET (ALLOCNO_CONFLICT_HARD_REGS (a),
> > 			    call_used_reg_set);
> > 	}
> >       else if (ALLOCNO_CALLS_CROSSED_NUM (a) != 0)
> > 	{
> > 	  IOR_HARD_REG_SET (ALLOCNO_TOTAL_CONFLICT_HARD_REGS (a),
> > 			    no_caller_save_reg_set);
> > 	  IOR_HARD_REG_SET (ALLOCNO_TOTAL_CONFLICT_HARD_REGS (a),
> > 			    temp_hard_reg_set);
> > 	  IOR_HARD_REG_SET (ALLOCNO_CONFLICT_HARD_REGS (a),
> > 			    no_caller_save_reg_set);
> > 	  IOR_HARD_REG_SET (ALLOCNO_CONFLICT_HARD_REGS (a),
> > 			    temp_hard_reg_set);
> > 	}
> >   
> 
> 
>