[Mesa-dev] [RFC] glsl-to-tgsi ARL generator small improvements

[Vincent Lejeune]

Hi,

These patches reworks sightly glsl-to-tgsi ir_dereference* visitor.
The first one is self explanatory.
The second one factor ir_dereference* in a separate visitor ; by itself,
this change does not bring anything to code generation, however it should
make easier to handle case where variable location is not standard, for
instance UBO. In addition glsl-to-tgsi should generate (U)MAD instead of
(U)MUL and (U)ADD when there is 2 level indirect addressing (which is not
very common at the moment).
Third patch should help glsl-to-tgsi to avoid generating redondant (U)ARL
opcode in indirect addressing. I tested it against piglit's
tests/shaders/glsl-fs-vec4-indexing-temp-src-in-loop.shader_test
and it removed a UARL instruction. As this patch changes the way relative
addressing is treated, it might regress in some situation so it needs more
testing that the previous ones.

Regards,
Vincent