[PATCH] Fix inlining checks wrt optimize attribute

[Jan Hubicka]

> 
> 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

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;