Previously, our variable renaming algorithm, while similar to the one in
the Cytron paper, was not the same. While I'm pretty sure it was correct,
it will be easier for readers of the code in the variable renaming pass if
it follows more closely. This commit removes the automatic stack popping
we were doing and replaces it with explicit popping like Cytron does.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
This commit seeks to make the lower_variables pass much more clear by
adding a pile of comments and re-arranging a few things. There are no
functional or algorithmic changes.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
As it was, we weren't ever using load_const in a non-SSA way. This allows
us to substantially simplify the load_const instruction. If we ever need a
non-SSA constant load, we can do a load_const and an imov.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Previously, we were just iterating over the program "in order" which
kind-of approximates a DFS, but not really. In particular, we got the
following case wrong:
loop {
a = 3;
if (foo) {
a = 5;
} else {
break;
}
use(a);
}
where use(a) would get 3 instead of 5 because of premature popping of the
SSA def stack. Now, since we do an actaul DFS, we should evaluate use(a)
immediately after a = 5 and we should be ok.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
We stopped generating predicates in glsl_to_nir some time ago. Right now,
it's all dead untested code that I'm not convinced always worked in the
first place. If we decide we want them back, we can revert this patch.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Previously, the condition was a scalar that applied to all components
simultaneously. As of this commit, the condition is a vector and each
component is switched seperately.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
nir_metadata_dirty was a terrible name because the parameter it takes is
the metadata to be preserved. This is really confusing because it looks
like it's doing the opposite of what it is actually doing. Now it's named
sensibly.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
We used to have the number of components built into the intrinsic. This
meant that all of our load/store intrinsics had vec1, vec2, vec3, and vec4
variants. This lead to piles of switch statements to generate the correct
intrinsic names, and introspection to figure out the number of components.
We can make things much nicer by allowing "vectorized" intrinsics.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
This pass analizes all of the load/store operations and, when a variable is
never aliased (potentially used by an indirect operation), it is lowered
directly to an SSA value. This pass translates to SSA directly and does
not require any fixup by the original to-SSA pass.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
