[CIR] Use data size in emitAggregateCopy for overlapping copies (#186702)
Add skip_tail_padding property to cir.copy to handle
potentially-overlapping
subobject copies directly, instead of falling back to cir.libc.memcpy.
When
set, the lowering uses the record's data size (excluding tail padding)
for
the memcpy length. This keeps typed semantics and promotability of
cir.copy.
Also fix CXXABILowering to preserve op properties when recreating
operations,
and expose RecordType::computeStructDataSize() for computing data size
of
padded record types.
llvm
348295ac - [CIR] Use data size in emitAggregateCopy for overlapping copies (#186702)
