Previously, it was only in the GatherScatterFlattenOpt optimization pass that
we added the per-lane offsets when we were indexing into varying data.
(Specifically, the case of float foo[]; int index; foo[index], where foo
is an array of varying elements rather than uniform elements.) Now, this
is done in the front-end as we're first emitting code.
In addition to the basic ugliness of doing this in an optimization pass,
it was also error-prone to do it there, since we no longer have access
to all of the type information that's around in the front-end.
No functionality or performance change.
scalar values (that ispc used to smear across the array/struct
elements). Now, initializers in variable declarations must be
{ }-delimited lists, with one element per struct member or array
element, respectively.
There were a few problems with the previous implementation of the
functionality to initialize from scalars. First, the expression
would be evaluated once per value initialized, so if it had side-effects,
the wrong thing would happen. Next, for large multidimensional arrays,
the generated code would be a long series of move instructions, rather
than loops (and this in turn made LLVM take a long time.)
While both of these problems are fixable, it's a non-trivial
amount of re-plumbing for a questionable feature anyway.
Fixes issue #50.
