There are precise rules for when calculations in GL must return the
same result, which are laid out in Appendix A ("Invariance"). The
relevant rule here:
"Rule 4 The same vertex or fragment shader will produce the same result when
run multiple times with the same input. The wording ‘the same
Hi,
"is_used_once" within an inexact transformation in nir_opt_algebraic can
lead to geometry differences with multi-pass rendering, causing incorrect
output. Here's an example to proof this:
Let's assume there is a pass that writes out some intermediate value from
the position calculation as a
