[flang-commits] [clang] [flang] [llvm] [mlir] [polly] [CMake][LLVM] Add PCH infrastructure and LLVMSupport PCH (PR #176420)

[Vitaly Buka via flang-commits]

================
@@ -1304,11 +1304,59 @@ if (LLVM_BUILD_INSTRUMENTED AND LLVM_BUILD_INSTRUMENTED_COVERAGE)
   message(FATAL_ERROR "LLVM_BUILD_INSTRUMENTED and LLVM_BUILD_INSTRUMENTED_COVERAGE cannot both be specified")
 endif()
 
+if(NOT DEFINED CMAKE_DISABLE_PRECOMPILE_HEADERS)
----------------
vitalybuka wrote:

And when I use the flag, I see hundreds of 

```
CMake Warning in benchmarks/CMakeLists.txt:
  Target "LLVMSupport" for the "DummyYAML" target's
  "PRECOMPILE_HEADERS_REUSE_FROM" property has set
  "DISABLE_PRECOMPILE_HEADERS"; ignoring.
```

https://github.com/llvm/llvm-project/pull/176420