[clang] [OpenMP] Introduce support for OMPX extensions and taskgraph frontend (PR #66919)

[Shilei Tian via cfe-commits]

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@@ -347,10 +347,6 @@ if(LIBOMP_OMPD_SUPPORT AND ((NOT LIBOMP_OMPT_SUPPORT) OR (NOT "${CMAKE_SYSTEM_NA
   set(LIBOMP_OMPD_SUPPORT FALSE)
 endif()
 
-# OMPX Taskgraph support
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shiltian wrote:

I'm not sure if I asked it before, but if possible can we run some task benchmark suites, like BOLT, to see the overhead? If no overhead, it'd be great to remove the macro.

https://github.com/llvm/llvm-project/pull/66919