[CLANG][OpenMP] Add support for OpenMP6.0 transparent clause

[zahiraam]

Add basic parsing and semantic support for transparent clause for task andtaskloop directives described in Section 17.9.6 of https://www.openmp.org/wp-content/uploads/OpenMP-API-Specification-6-0.pdf .

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[kparzysz]

Sorry for the delay in reviewing.

The flang changes are actually not correct---what was there before was. The transparent clause takes an expression, not a constant.

[kparzysz]

Undo all changes in flang/*, ClauseT.h, and restore the "isValueOptional" in OMP.td. That should make it ok.

[zahiraam]

Undo all changes in flang/*, ClauseT.h, and restore the "isValueOptional" in OMP.td. That should make it ok.

Thanks! will try that.

[github-actions]

🐧 Linux x64 Test Results

• 192823 tests passed
• 6177 tests skipped

[kparzysz]

LGTM, thanks!

Edit: Please wait for Alexey's review.

[zahiraam]

LGTM, thanks!

Edit: Please wait for Alexey's review.

Thanks!

[alexey-bataev]

Do we have support for this in runtime library? If not, this definitely requires initial support in runtime at first

[zahiraam]

Do we have support for this in runtime library? If not, this definitely requires initial support in runtime at first

No. Should the runtime change be a preliminary PR to this one? I am assuming that a Transparent flag needs to be added to kmp_tasking_flags.

[zahiraam]

Runtime changes proposed here: #168873

[zahiraam]

Runtime changes proposed here: #168873

@alexey-bataev Would adding the flag in #168873 be enough for this PR to be merged?