fix ConstantExpr handling in CreateAugmentedPrimal

[ZuseZ4]

llvm's copyFunctionInto won't add constantexpr to the vmap, since It can be shared, similar to constantData.

fixes #721

[ZuseZ4]

@wsmoses MacOs fails, but not sure what the error should tell me?

[ZuseZ4]

I also had an issue on Linux on an earlier commit here: https://github.com/EnzymeAD/Enzyme/runs/7436868577?check_suite_focus=true
Maybe it's just the infrastructure having a bad day?
Can someone working on MacOS test it? I took the run command from the Reverse/constant.ll example, so I see no reason why my new test should fail on macOS.

[tgymnich]

I was able to reproduce the issue on my machine. I will look into it soon.

[tgymnich]

It seems like the inversionAllocs are marked unreachable and successively deleted (EnzymeLogic.cpp:2235). The crash then happens when we want to access inversionAllocs the next time at EnzymeLogic.cpp:2301. shadowReturnUsed seems to be true on macOS and false on Linux.

[wsmoses]

@ZuseZ4 the solution then is to move the invertpointer calls (

Enzyme/enzyme/Enzyme/EnzymeLogic.cpp

Line 2295 in e8ed87c

if (shadowReturnUsed) {

) prior to the deletion/move of inversionAllocas

[ZuseZ4]

Thanks @tgymnich @wsmoses.

[tgymnich]

@ZuseZ4 Your added test still triggers assertions. They just don't show up in our CI.

    for (auto pair : toVirtual) {
      auto CI = pair.first;
      Constant *fn = dyn_cast<Constant>(CI->getArgOperand(0));
      if (!fn) {
        EmitFailure("IllegalVirtual", CI->getDebugLoc(), CI,
                    "Cannot create virtual version of non-constant value ", *CI,
                    *CI->getArgOperand(0));
        return false;
      }
      TypeAnalysis TA(Logic.PPC.FAM);

      auto Arch =
          llvm::Triple(
              CI->getParent()->getParent()->getParent()->getTargetTriple())
              .getArch();

      bool AtomicAdd = Arch == Triple::nvptx || Arch == Triple::nvptx64 ||
                       Arch == Triple::amdgcn;

      auto val = GradientUtils::GetOrCreateShadowConstant(
          Logic, TLI, TA, fn, pair.second, /*width*/ 1, AtomicAdd);
      CI->replaceAllUsesWith(ConstantExpr::getPointerCast(val, CI->getType()));
      CI->eraseFromParent();
      Changed = true;
    }

CI->getType() => void
val->getType() => i8*