SPIRV-Cross/reference/opt
Hans-Kristian Arntzen 461f1506e7 Do not eagerly invalidate all active variables on a branch.
This is not necessary, as we must emit an invalidating store before we
potentially consume an invalid expression. In fact, we're a bit
conservative here in this case for example:

int tmp = variable;
if (...)
{
    variable = 10;
}
else
{
    // Consuming tmp here is fine, but it was
    // invalidated while emitting other branch.
    // Technically, we need to study if there is an invalidating store
    // in the CFG between the loading block and this block, and the other
    // branch will not be a part of that analysis.
    int tmp2 = tmp * tmp;
}

Fixing this case means complex CFG traversal *everywhere*, and it feels like overkill.

Fixing this exposed a bug with access chains, so fix a bug where expression dependencies were not
inherited properly in access chains. Access chains are now considered forwarded if there
is at least one dependency which is also forwarded.
2019-07-24 11:17:30 +02:00
..
shaders Do not eagerly invalidate all active variables on a branch. 2019-07-24 11:17:30 +02:00
shaders-hlsl Do not disable temporary forwarding when we suppress usage tracking. 2019-07-23 19:18:44 +02:00
shaders-msl Do not eagerly invalidate all active variables on a branch. 2019-07-24 11:17:30 +02:00