[OpenACC][CIR] Implement 'self' lowering on compute constructs (#135851)
This is our first attempt at lowering a clause that is an 'operand' in
the OpenACC operand, so it does quite a bit of refactoring. My previous
plans on how to emit the clauses was not viable, so we instead do
'create the op, then use the visitor to fill in the operands'. This
resulted in the 'applyAttributes' function getting removed and a few
other functions simplified.
Additionally, it requires setting the insertion point a little to make
sure we're inserting 'around' the operation correctly.
Finally, since the OpenACC dialect only understands the MLIR types, we
had to introduce a use of the unrealized-conversion-cast, which we'll
probably getting good use out of in the future.
llvm-project
af63e1b5 - [OpenACC][CIR] Implement 'self' lowering on compute constructs (#135851)
