RE: [PATCH, C/C++] Add -fno-float to forbid floating point data types

["Joseph S. Myers" <joseph at codesourcery dot com>]

On Tue, 12 Aug 2014, Thomas Preud'homme wrote:

> 3) __builtin_sqrt
> 
> True, I shall try if it works with builtins. Thanks for the advice.

In addition to built-in functions, you have built-in typedefs.  I don't 
think your code would catch uses of __fp16, __float128 etc. (such types 
are defined as built-in typedefs by back ends at present, not as 
keywords).

Rather than making back ends have their own conditionals, the built-in 
typedef issue could be dealt with by checking whether the type given by a 
sequence of declspecs (in a declaration or type name) is a floating-point 
type (in or after c_finish_declspecs - in the __auto_type case, getting a 
floating-point type means the initializer has such a type and you should 
catch things when handling the initializer).

Also consider built-in typedefs and functions involving vectors of 
floating-point types, as well as the simple real and complex types.

> 4) Objective C
> 
> As said in the description, I'm not opposed to adding other language.
> It's easier to add another language than remove one after the fact
> because very few people use it. Therefore I preferred to have
> just C and C++ for now which is what I expect most of the users of
> such a switch to be interested in. Do you think I should add support
> for that language up front or can it wait a later version of the patch
> once people started to use it?

The presumption should be that an option for C also applies to Objective-C 
(and likewise for C++ options and Objective-C++), unless there is a 
concrete reason this is problematic (i.e. an Objective-C feature that 
needs special handling to implement the option).

-- 
Joseph S. Myers
joseph@codesourcery.com