[PATCH vkd3d v3 2/5] vkd3d-shader/hlsl: Rename hlsl_ir_expr_op members.

[Matteo Bruni]

Signed-off-by: Matteo Bruni <mbruni at codeweavers.com>
---
For reference: originally the plan was for HLSL_IR_EXPR to only cover
"mathematical" expressions, or more specifically, pure expressions
that could be transformed and moved around (e.g. hoisted out of a
loop) without any problem. In that world statements that don't fall
under that banner, like texture sampling instructions, would not be
expressions.

My original setup was inspired by the Mesa GLSL frontend (at the
time). It looks like NIR also followed along the same line, with what
they call ALU instructions covering our expressions and intrinsic
instructions basically matching everything that isn't an ALU
instruction or a jump (or SSA stuff).

Now, that concept doesn't necessarily need to be preserved in the same
form. We probably still need some way to separate "pure" expressions
from the rest though. What's your idea in this regard?