[clang] [CIR][OpenMP] Add support for combined target parallel directives (PR #207019)

[Sergio Afonso via cfe-commits]

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@@ -361,9 +436,35 @@ mlir::LogicalResult CIRGenFunction::emitOMPTargetExitDataDirective(
 }
 mlir::LogicalResult CIRGenFunction::emitOMPTargetParallelDirective(
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skatrak wrote:

I guess we're missing the combined construct dispatch and have to manually handle combined constructs per-leaf like this. Not a change request for this PR, but something to think about since the list of supported OpenMP combined constructs is pretty massive and this approach wouldn't scale.

I think that should also make the implementation for `leafIsCombined` and `getLeafClauses` potentially more efficient, since we shouldn't have to decompose and search for the right leaf every time.

https://github.com/llvm/llvm-project/pull/207019