[clang] [flang] [llvm] Add IR Profile-Guided Optimization (IR PGO) support to the Flang compiler (PR #136098)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-nvptx-nvidia-ubuntu` running on `as-builder-7` while building `clang,flang,llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/180/builds/18512

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (build-unified-tree) failure: build (failure)
...
In file included from /home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/tools/llvm-link/llvm-link.cpp:36:
/home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/include/llvm/Transforms/IPO/FunctionImport.h: In constructor ‘llvm::FunctionImporter::ImportListsTy::ImportListsTy()’:
/home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/include/llvm/Transforms/IPO/FunctionImport.h:273:33: warning: member ‘llvm::FunctionImporter::ImportListsTy::ImportIDs’ is used uninitialized [-Wuninitialized]
  273 |     ImportListsTy() : EmptyList(ImportIDs) {}
      |                                 ^~~~~~~~~
/home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/include/llvm/Transforms/IPO/FunctionImport.h: In constructor ‘llvm::FunctionImporter::ImportListsTy::ImportListsTy(size_t)’:
/home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/include/llvm/Transforms/IPO/FunctionImport.h:274:44: warning: member ‘llvm::FunctionImporter::ImportListsTy::ImportIDs’ is used uninitialized [-Wuninitialized]
  274 |     ImportListsTy(size_t Size) : EmptyList(ImportIDs), ListsImpl(Size) {}
      |                                            ^~~~~~~~~
45.744 [637/11/2102] Linking CXX shared library lib/libLLVMFrontendDriver.so.21.0git
FAILED: lib/libLLVMFrontendDriver.so.21.0git 
: && /usr/bin/c++ -fPIC -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -Wl,-z,defs -Wl,-z,nodelete -fuse-ld=gold   -Wl,--gc-sections -shared -Wl,-soname,libLLVMFrontendDriver.so.21.0git -o lib/libLLVMFrontendDriver.so.21.0git lib/Frontend/Driver/CMakeFiles/LLVMFrontendDriver.dir/CodeGenOptions.cpp.o  -Wl,-rpath,"\$ORIGIN/../lib:/home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/build/lib:"  lib/libLLVMAnalysis.so.21.0git  lib/libLLVMCore.so.21.0git  lib/libLLVMSupport.so.21.0git  -Wl,-rpath-link,/home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/build/lib && :
lib/Frontend/Driver/CMakeFiles/LLVMFrontendDriver.dir/CodeGenOptions.cpp.o:CodeGenOptions.cpp:function llvm::driver::getDefaultProfileGenName[abi:cxx11]():(.text._ZN4llvm6driver24getDefaultProfileGenNameB5cxx11Ev+0x7): error: undefined reference to 'llvm::DebugInfoCorrelate'
lib/Frontend/Driver/CMakeFiles/LLVMFrontendDriver.dir/CodeGenOptions.cpp.o:CodeGenOptions.cpp:function llvm::driver::getDefaultProfileGenName[abi:cxx11]():(.text._ZN4llvm6driver24getDefaultProfileGenNameB5cxx11Ev+0x1e): error: undefined reference to 'llvm::ProfileCorrelate'
collect2: error: ld returned 1 exit status
45.949 [637/4/2109] Linking CXX shared library lib/libLLVMTransformUtils.so.21.0git
53.427 [637/2/2111] Building CXX object lib/LTO/CMakeFiles/LLVMLTO.dir/LTO.cpp.o
In file included from /home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/include/llvm/LTO/LTO.h:32,
                 from /home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/lib/LTO/LTO.cpp:13:
/home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/include/llvm/Transforms/IPO/FunctionImport.h: In constructor ‘llvm::FunctionImporter::ImportListsTy::ImportListsTy()’:
/home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/include/llvm/Transforms/IPO/FunctionImport.h:273:33: warning: member ‘llvm::FunctionImporter::ImportListsTy::ImportIDs’ is used uninitialized [-Wuninitialized]
  273 |     ImportListsTy() : EmptyList(ImportIDs) {}
      |                                 ^~~~~~~~~
/home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/include/llvm/Transforms/IPO/FunctionImport.h: In constructor ‘llvm::FunctionImporter::ImportListsTy::ImportListsTy(size_t)’:
/home/buildbot/worker/as-builder-7/llvm-nvptx-nvidia-ubuntu/llvm-project/llvm/include/llvm/Transforms/IPO/FunctionImport.h:274:44: warning: member ‘llvm::FunctionImporter::ImportListsTy::ImportIDs’ is used uninitialized [-Wuninitialized]
  274 |     ImportListsTy(size_t Size) : EmptyList(ImportIDs), ListsImpl(Size) {}
      |                                            ^~~~~~~~~
54.081 [637/1/2112] Building CXX object lib/CodeGen/AsmPrinter/CMakeFiles/LLVMAsmPrinter.dir/AsmPrinter.cpp.o
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/136098