[Mesa-dev] Mesa (shader-work): glsl: introduce ir_binop_all_equal and ir_binop_any_equal, allow vector cmps

[Luca Barbieri]

> And never mind that you can't make a conformant OpenGL driver with
> Gallium due to the impossibility of software fallbacks.

Well, you could use the failover module to use softpipe for fallbacks,
but no one does, for the following reasons:
1. Modern hardware doesn't need any software fallbacks, and at most
you need to "emulate" things with ad-hoc shaders (possibly compute
shaders)
2. Software fallbacks are mostly useless because a terribly slow
implementation is not significantly more useful than a broken uone