[C/C++ PATCH] Fix ICE in get_atomic_generic_size (PR c++/83059)

[Nathan Sidwell]

On 11/20/2017 04:03 PM, Jakub Jelinek wrote:
> Hi!
> 
> Not all INTEGER_CSTs satisfy tree_fits_uhwi_p, and those that don't
> ICE in tree_to_uhwi.  But, what the memmodel_base function actually
> does is mask only the 16 low bits, the upper bits are reserved for
> target dependent flags and -Winvalid-memory-model already warns
> about those during expansion.  So it makes no sense to warn about say
> (-1 << 16) here, thus I'm using TREE_INT_CST_LOW instead of tree_to_*hwi,
> because we really care just about the low 16 bits thereof.


> -	  int i = tree_to_uhwi (p);
> -	  if (i < 0 || (memmodel_base (i) >= MEMMODEL_LAST))
> -	    {
> -	      warning_at (loc, OPT_Winvalid_memory_model,
> -			  "invalid memory model argument %d of %qE", x + 1,
> -			  function);
> -	    }
> +	  if (memmodel_base (TREE_INT_CST_LOW (p)) >= MEMMODEL_LAST)
> +	    warning_at (loc, OPT_Winvalid_memory_model,
> +			"invalid memory model argument %d of %qE", x + 1,
> +			function);

Ok with a comment mentioning memmodel_base only looks at low-order bits.

nathan

-- 
Nathan Sidwell