This commit extends the SROA interfaces to ensure the interface
instantiations can communicate newly created allocators to the
algorithm. This ensures that the SROA implementation does no longer
require re-walking the IR to find new allocators.
This commit changes the `MemorySlotInterface` back to using `OpBuilder`
instead of a rewriter. This was originally introduced in
https://reviews.llvm.org/D150432 but it was shown that patterns are a
bad idea for both Mem2Reg and SROA.
Mem2Reg suffers from the usage of a rewriter due to being forced to
create new basic blocks. This is an issue, as it leads to the
invalidation of the dominance information, which can be expensive to
recompute.
This commit expends the Mem2Reg and SROA interface methods with passed
in handles to a `DataLayout` structure. This is done to avoid
superfluous retreiving of data layouts during each conversion of
intrinsics.
This change, additionally, enables subsequent changes to make the LLVM
dialect implementation of these interfaces type agnostic.
This commit changes MLIR's SROA implementation back from being pattern
based into a full pass. This is beneficial for upcoming changes that
rely more heavily on the datalayout.
Unfortunately, this change required substantial test changes, as the
IRBuilder no cleans up the IR.
This revision introduces a generic implementation of Scalar Replacement
Of Aggregates. In contrast to the implementation in LLVM, this focuses
on the core of SROA: destructuring aggregates. By implementing
interfaces on allocators and accessors, memory allocators can be
destructured into smaller allocators, through the MemorySlot
abstraction.
This pass only works on aggregates that are accessed in a "type-safe"
way, that is within the bounds and respecting the type of a given memory
slot. The destructuring pattern and functions only peel off the first
layer of aggregates and can safely be applied repeatedly. For
convenience, the transformation is also available as a pass that will
apply the pattern repeatedly.
Depends on D149958
Reviewed By: gysit
Differential Revision: https://reviews.llvm.org/D150186
