On the swrast driver incorrect rendering is produced, and on the i965 driver a link error is produced.
error: unresolved reference to function `_half'
i965 driver doesn't yet support uninlined function calls. Move to using a single return statement at the end of the function to work around it.
Author: Ian Romanick <email@example.com>
Date: Wed Aug 11 16:58:25 2010 -0700
glsl2: Don't declare a variable called sig that shadows the other one
Accidentally having a variable called 'sig' within an if-statement
cause the higher scope 'sig' to always be NULL. As a result a new
function signature was created for a function definition even when one
already existed from a prototype declaration.
Fixes piglit test case glsl-function-prototype (bugzilla #29520).