[MLIR][OpenMP] Added OMPIRBuilder support for use_device_ptr clause

[TIFitis]

Summary

This patch adds OpenMP IRBuilder support for the use_device_ptr clause for Target Data directive.

Depends on D146557

[TIFitis]

llvm/lib/Frontend/OpenMP/OMPIRBuilder.cpp

4069–4070

use_dev_ptr operands must always be pointer types so I think it is safe to always just create a ptr for them.

However if we want to support typed pointers then we would have to create something like:
Builder.CreateAlloca(UseDeviceOp.first->getType()->getPointerElementType())

This is not possible as getPointerElementType is deprecated and I couldn't find any alternative for this.

4175–4185

I have commented out some code in OpenMPToLLVMIRTranslation.cpp::1489. I think that is a better way of generating code for the use_dev_ptr, but the mapValue doesn't allow remapping.

This I am stuck with letting it use the old value inside the region and replacing it later here.

llvm/unittests/Frontend/OpenMPIRBuilderTest.cpp

5017–5025

This unit test fails because of opaque pointer mismatch, The unit test runs with opaque pointers disabled however the my code only runs with it enabled.

I could not find a reasonable way to support typed pointers, I have explained this in another comment.

[TIFitis]

Split use_dev_ptr test into two.

[TIFitis]

Rebased

[TIFitis]

Need to change this patch to account for all the clang migration changes and make use of those functions.