[Mesa-dev] [PATCH] ir_to_mesa: Fix reallocating registers for shaders with loops

[Kenneth Graunke]

On 03/27/2011 01:17 AM, Tom Stellard wrote:
> Registers that are used inside of loops need to be considered live
> starting with the very first instruction in the loop.
>
> This fixes the following piglit tests on r300:
> - glsl-fs-loop-redundant-condition
> - glsl-vs-loop-redundant-condition
> - glsl-vs-vec4-indexing-temp-dst-in-loop
>
> NOTE: This is a candidate for the 7.9 and 7.10 branches.

This also fixes glsl-vs-loop-redundant-condition on i965.

It doesn't fix glsl-fs-loop-redunant-condition on i965, but that's 
hardly surprising considering we're using a different IR and register 
allocator for FS.

Strangely, glsl-vs-vec4-indexing-temp-dst-inloop already passes on i965. 
  I'm not sure why it would work on i965 but not r300 if the bug is in 
the common code.  But it's quite possible.