Backends want to be able to do special things with constant values such as
put them into immediates or make decisions based on whether or not a value
is constant. Before, constants always got lowered to a load_const into a
register and then a register use. Now we leave constants as SSA values so
backends can special-case them if they want. Since handling constant SSA
values is trivial, this shouldn't be a problem for backends.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
This pass is still fairly basic. It only handles ALU operations, constant
loads, and phi nodes. No texture ops or intrinsics yet.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
The unlink_blocks function moves successors around to make sure that, if
there is a remaining successor, it is in the first successors slot and not
the second. To fix this, we simply get both successors up front.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
We also make the return types match GLSL. The GLSL spec specifies that
findMSB and findLSB return a signed integer. Previously, nir had them
return unsigned. This updates nir's behavior to match what GLSL expects.
We also update the nir-to-fs generator to take the new instructions. While
we're at it, we fix the case where the input to findMSB is zero.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
These indices should now be reasonably stable/consistent. Redoing the
indices in the print functions makes it harder to debug problems.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Some time while refactoring things to make it look nicer before pushing to
master, I completely broke the function. This fixes it to be correct.
Just goes to show you why you souldn't push code that has no users yet...
Signed-off-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
This commit rewrites the out-of-SSA pass to not be nearly as naieve. It's
based on "Revisiting Out-of-SSA Translation for Correctness, Code Quality,
and Efficiency" by Boissinot et. al. It should be fairly close to
state-of-the art.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Since we don't actually have an "if" instruction, this is a very common
pattern when iterating over instructions. This adds a helper function for
it to make things a little less painful.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
This pass is kind of stupidly implemented but it should be enough to get us
up and going. We probably want something better that doesn't generate all
of the redundant moves eventually. However, the i965 backend should be
able to handle the movs, so I'm not too worried about it in the short term.
Previously, emit_general_interpolation took an ir_variable and pulled the
information it needed from that. This meant that in fs_fp, we were
constructing a dummy ir_variable just to pass into it. This commit makes
emit_general_interpolation take only the information it needs and gets rid
of the fs_fp cruft.
Reviewed-by: Connor Abbott <cwabbott0@gmail.com>
Jason Ekstrand