[Mesa-dev] [PATCH] glsl: Properly handle ldexp(0.0f, non-zero-exp).

[Kenneth Graunke]

On Wednesday, April 13, 2016 3:46:29 PM PDT Matt Turner wrote:
> On Wed, Apr 13, 2016 at 12:07 PM, Matt Turner <mattst88 at gmail.com> wrote:
> > ---
> 
> i965 is going to stop using this code, but I thought it'd be nice to
> fix this and also to note what is the remaining failure on the dEQP
> ldexp tests.
> 
> The GLSL spec says "If this product is too large to be represented in
> the floating-point type, the result is undefined."
> 
> This implementation of ldexp doesn't return infinity for inputs of
> infinity. Arguably, that's okay depending on how you interpret that
> text.
> 
> It's probably simple to handle this in the current code, or
> alternatively someone could port Jason's ldexp lowering code from NIR
> to GLSL which is also fewer instructions.
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It makes sense to fix this up for posterity, if nothing else - we might
come back to this someday (no idea why), and it'd be nice to find the
improved version.

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
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