[PATCH] Fix inlining checks wrt optimize attribute

[Richard Biener]

On Thu, 22 Jan 2015, Jan Hubicka wrote:

> > 
> > As said in the other thread - this makes sure we don't perform inlining
> > that might end up generating invalid code.  It also preserves
> > user-provided optimize attributes more properly.
> > 
> > Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
> > 
> > Richard.
> > 
> > 2015-01-22  Richard Biener  <rguenther@suse.de>
> > 
> > 	* ipa-inline.c (can_inline_edge_p): Disable inlining of edges
> > 	with IL incompatible options.  Properly honor user optimize
> > 	attributes.
> 
> Thanks, in fact I had similar patch in queue, just wanted to catch you on IRC
> and discuss posibility of making this a flag in common.opt

Sure - I briefly considered this but we're in stage4 now so I was just
fixing the obvious correctness issues.

We also have to fix

  /* Don't inline if the callee can throw non-call exceptions but the
     caller cannot.
     FIXME: this is obviously wrong for LTO where STRUCT_FUNCTION is 
missing.
     Move the flag into cgraph node or mirror it in the inline summary.  
*/
  else if (callee_fun && callee_fun->can_throw_non_call_exceptions
           && !(caller_fun && caller_fun->can_throw_non_call_exceptions))
    {
      e->inline_failed = CIF_NON_CALL_EXCEPTIONS;
      inlinable = false;
    }

in some way (eventually we can just use opt_for_fn 
()->flag_non_call_exceptions).

Richard.

> Honza
> > 
> > Index: gcc/ipa-inline.c
> > ===================================================================
> > --- gcc/ipa-inline.c	(revision 219929)
> > +++ gcc/ipa-inline.c	(working copy)
> > @@ -404,17 +404,56 @@ can_inline_edge_p (struct cgraph_edge *e
> >       optimization attribute.  */
> >    else if (caller_tree != callee_tree)
> >      {
> > -      /* gcc.dg/pr43564.c.  Look at forced inline even in -O0.  */
> > -      if (DECL_DISREGARD_INLINE_LIMITS (callee->decl))
> > +      /* There are some options that change IL semantics which means
> > +         we cannot inline in these cases for correctness reason.
> > +	 Not even for always_inline declared functions.  */
> > +      /* Strictly speaking only when the callee contains signed integer
> > +         math where overflow is undefined.  */
> > +      if ((opt_for_fn (e->caller->decl, flag_strict_overflow)
> > +	   != opt_for_fn (e->caller->decl, flag_strict_overflow))
> > +	  || (opt_for_fn (e->caller->decl, flag_wrapv)
> > +	      != opt_for_fn (e->caller->decl, flag_wrapv))
> > +	  || (opt_for_fn (e->caller->decl, flag_trapv)
> > +	      != opt_for_fn (e->caller->decl, flag_trapv))
> > +	  /* Strictly speaking only when the callee contains memory
> > +	     accesses that are not using alias-set zero anyway.  */
> > +	  || (opt_for_fn (e->caller->decl, flag_strict_aliasing)
> > +	      != opt_for_fn (e->caller->decl, flag_strict_aliasing))
> > +	  /* Strictly speaking only when the callee uses FP math.  */
> > +	  || (opt_for_fn (e->caller->decl, flag_rounding_math)
> > +	      != opt_for_fn (e->caller->decl, flag_rounding_math))
> > +	  || (opt_for_fn (e->caller->decl, flag_trapping_math)
> > +	      != opt_for_fn (e->caller->decl, flag_trapping_math))
> > +	  || (opt_for_fn (e->caller->decl, flag_unsafe_math_optimizations)
> > +	      != opt_for_fn (e->caller->decl, flag_unsafe_math_optimizations))
> > +	  || (opt_for_fn (e->caller->decl, flag_finite_math_only)
> > +	      != opt_for_fn (e->caller->decl, flag_finite_math_only))
> > +	  || (opt_for_fn (e->caller->decl, flag_signaling_nans)
> > +	      != opt_for_fn (e->caller->decl, flag_signaling_nans))
> > +	  || (opt_for_fn (e->caller->decl, flag_cx_limited_range)
> > +	      != opt_for_fn (e->caller->decl, flag_cx_limited_range))
> > +	  || (opt_for_fn (e->caller->decl, flag_signed_zeros)
> > +	      != opt_for_fn (e->caller->decl, flag_signed_zeros))
> > +	  || (opt_for_fn (e->caller->decl, flag_associative_math)
> > +	      != opt_for_fn (e->caller->decl, flag_associative_math))
> > +	  || (opt_for_fn (e->caller->decl, flag_reciprocal_math)
> > +	      != opt_for_fn (e->caller->decl, flag_reciprocal_math))
> > +	  /* Strictly speaking only when the callee contains function
> > +	     calls that may end up setting errno.  */
> > +	  || (opt_for_fn (e->caller->decl, flag_errno_math)
> > +	      != opt_for_fn (e->caller->decl, flag_errno_math)))
> > +	{
> > +	  e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
> > +	  inlinable = false;
> > +	}
> > +      /* gcc.dg/pr43564.c.  Apply user-forced inline even at -O0.  */
> > +      else if (DECL_DISREGARD_INLINE_LIMITS (callee->decl)
> > +	       && lookup_attribute ("always_inline",
> > +				    DECL_ATTRIBUTES (callee->decl)))
> >  	;
> > -      /* When user added an attribute, honnor it.  */
> > -      else if ((lookup_attribute ("optimize", DECL_ATTRIBUTES (caller->decl))
> > -		|| lookup_attribute ("optimize",
> > -				     DECL_ATTRIBUTES (callee->decl)))
> > -	       && ((opt_for_fn (caller->decl, optimize)
> > -		   > opt_for_fn (callee->decl, optimize))
> > -		   || (opt_for_fn (caller->decl, optimize_size)
> > -		       != opt_for_fn (callee->decl, optimize_size))))
> > +      /* When user added an attribute to the callee honor it.  */
> > +      else if (lookup_attribute ("optimize", DECL_ATTRIBUTES (callee->decl))
> > +	       && opts_for_fn (caller->decl) != opts_for_fn (callee->decl))
> >  	{
> >  	  e->inline_failed = CIF_OPTIMIZATION_MISMATCH;
> >  	  inlinable = false;
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Jennifer Guild,
Dilip Upmanyu, Graham Norton HRB 21284 (AG Nuernberg)