fixes#151764
This fix has two parts first we track all lifetime intrinsics and if
they are users of an alloca of a target extention like dx.RawBuffer then
we eliminate those memory intrinsics when we visit the alloca.
We do step one to allow us to use the Dead Store Elimination Pass. This
removes the alloca and simplifies the use of the target extention back
to using just the global. That keeps things in a form the
DXILBitcodeWriter is expecting.
Obviously to pull this off we needed to bring back the legacy pass
manager plumbing for the DSE pass and hook it up into the DirectX
backend.
The net impact of this change is that DML shader pass rate went from
89.72% (4268 successful compilations) to 90.98% (4328 successful
compilations).
fixes#140819
SROA pass is making it so that some globals get loaded into stack
allocations. This means we find an alloca where we use to expect a load
and now need to walk an alloca -> store -> maybe load chain before we
find the global. Doing so fixes All but two instances of #137715 And
fixes every instance of `Load of "8.sroa.0" is not a global resource
handle we are currently seeing in the DML shaders.
Since the `DXILResourceImplicitBinding` pass has been moved after `DXILForwardHandleAccesses` pass the forward-handle pass needs to handle `llvm.dx.resource.handlefromimplicitbinding` calls as well.
This pass attempts to forward resource handle creation to accesses of
the handle global. This avoids dependence on optimizations like CSE and
GlobalOpt for correctness of DXIL.
Fixes#134574.
