r227956 - Add some overloads so that floating point literals can be AST matched properly.

[Kim Gräsman]

Hi Daniel,

On Tue, Feb 3, 2015 at 10:45 AM, Daniel Jasper <djasper at google.com> wrote:
> Author: djasper
> Date: Tue Feb  3 03:45:52 2015
> New Revision: 227956
>
> URL: http://llvm.org/viewvc/llvm-project?rev=227956&view=rev
> Log:
> Add some overloads so that floating point literals can be AST matched properly.
>
> I am not entirely sure whether the implemented sematics are ideal. In
> particular, should floatLiteral(equals(0.5)) match "0.5f" and should
> floatLiteral(equals(0.5f)) match "0.5". With the overloads in this
> patch, the answer to both questions is yes, but I am happy to change
> that.

This looks scary to me given the general difficulties in comparing floats:
https://randomascii.wordpress.com/2013/07/16/floating-point-determinism/

Or is it safe because they're both fixed literals and not the result
of a calculation? Then again, nothing prevents me from doing;

  floatLiteral(equals(sqrt(AnArgument)))

- Kim