ControlHeightReduction: Remove assert check in shouldApply

[MatzeB]

Summary

Remove assertion checking for non-empty ProfileSummaryInfo.

[MatzeB]

I keep hitting this assertion when using LTO+PGO with an assertion enabled LLVM/clang build for the llvm-test-suite. While I haven't debugged this to the end, I suspect there is some oddities in the llvm-test-suite build not passing the ThinLTO or PGO parameters down properly to the google-benchmark files in there and ThinLTO choosing a partition where none of the functions has profile info.

While this is a somewhat badly setup build it should not hit an assertion in the compiler, can we drop this?

[nikic]

LGTM

We also hit this assert here: https://github.com/rust-lang/rust/pull/101403#issuecomment-1272519304 I believe in that case the problem is that some of the modules participating in ThinLTO do not have PGO information (and that's fine).

[Kobzol]

Hi @MatzeB, this assert is currently blocking progress on using LTO for the Rust compiler. If there any not any objections to this patch, could you land it please? Thanks!

llvm/lib/Transforms/Instrumentation/ControlHeightReduction.cpp

if (ForceCHR)
     return true;
 
   if (!CHRModuleList.empty() || !CHRFunctionList.empty()) {
     if (CHRModules.count(F.getParent()->getName()))
       return true;
     return CHRFunctions.count(F.getName());
   }
 
-  assert(PSI.hasProfileSummary() && "Empty PSI?");
   return PSI.isFunctionEntryHot(&F);
 }
 
 static void LLVM_ATTRIBUTE_UNUSED dumpIR(Function &F, const char *Label,
                                          CHRStats *Stats) {
   StringRef FuncName = F.getName();
   StringRef ModuleName = F.getParent()->getName();
   (void)(FuncName); // Unused in release build.