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diff --git a/contrib/llvm-project/llvm/lib/Transforms/IPO/PruneEH.cpp b/contrib/llvm-project/llvm/lib/Transforms/IPO/PruneEH.cpp
new file mode 100644
index 000000000000..cb3915dfb678
--- /dev/null
+++ b/contrib/llvm-project/llvm/lib/Transforms/IPO/PruneEH.cpp
@@ -0,0 +1,269 @@
+//===- PruneEH.cpp - Pass which deletes unused exception handlers ---------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a simple interprocedural pass which walks the
+// call-graph, turning invoke instructions into calls, iff the callee cannot
+// throw an exception, and marking functions 'nounwind' if they cannot throw.
+// It implements this as a bottom-up traversal of the call-graph.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/CallGraph.h"
+#include "llvm/Analysis/CallGraphSCCPass.h"
+#include "llvm/Analysis/EHPersonalities.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/IR/CFG.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/InlineAsm.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/IPO.h"
+#include <algorithm>
+using namespace llvm;
+
+#define DEBUG_TYPE "prune-eh"
+
+STATISTIC(NumRemoved, "Number of invokes removed");
+STATISTIC(NumUnreach, "Number of noreturn calls optimized");
+
+namespace {
+  struct PruneEH : public CallGraphSCCPass {
+    static char ID; // Pass identification, replacement for typeid
+    PruneEH() : CallGraphSCCPass(ID) {
+      initializePruneEHPass(*PassRegistry::getPassRegistry());
+    }
+
+    // runOnSCC - Analyze the SCC, performing the transformation if possible.
+    bool runOnSCC(CallGraphSCC &SCC) override;
+
+  };
+}
+static bool SimplifyFunction(Function *F, CallGraph &CG);
+static void DeleteBasicBlock(BasicBlock *BB, CallGraph &CG);
+
+char PruneEH::ID = 0;
+INITIALIZE_PASS_BEGIN(PruneEH, "prune-eh",
+                "Remove unused exception handling info", false, false)
+INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
+INITIALIZE_PASS_END(PruneEH, "prune-eh",
+                "Remove unused exception handling info", false, false)
+
+Pass *llvm::createPruneEHPass() { return new PruneEH(); }
+
+static bool runImpl(CallGraphSCC &SCC, CallGraph &CG) {
+  SmallPtrSet<CallGraphNode *, 8> SCCNodes;
+  bool MadeChange = false;
+
+  // Fill SCCNodes with the elements of the SCC.  Used for quickly
+  // looking up whether a given CallGraphNode is in this SCC.
+  for (CallGraphNode *I : SCC)
+    SCCNodes.insert(I);
+
+  // First pass, scan all of the functions in the SCC, simplifying them
+  // according to what we know.
+  for (CallGraphNode *I : SCC)
+    if (Function *F = I->getFunction())
+      MadeChange |= SimplifyFunction(F, CG);
+
+  // Next, check to see if any callees might throw or if there are any external
+  // functions in this SCC: if so, we cannot prune any functions in this SCC.
+  // Definitions that are weak and not declared non-throwing might be
+  // overridden at linktime with something that throws, so assume that.
+  // If this SCC includes the unwind instruction, we KNOW it throws, so
+  // obviously the SCC might throw.
+  //
+  bool SCCMightUnwind = false, SCCMightReturn = false;
+  for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end();
+       (!SCCMightUnwind || !SCCMightReturn) && I != E; ++I) {
+    Function *F = (*I)->getFunction();
+    if (!F) {
+      SCCMightUnwind = true;
+      SCCMightReturn = true;
+    } else if (!F->hasExactDefinition()) {
+      SCCMightUnwind |= !F->doesNotThrow();
+      SCCMightReturn |= !F->doesNotReturn();
+    } else {
+      bool CheckUnwind = !SCCMightUnwind && !F->doesNotThrow();
+      bool CheckReturn = !SCCMightReturn && !F->doesNotReturn();
+      // Determine if we should scan for InlineAsm in a naked function as it
+      // is the only way to return without a ReturnInst.  Only do this for
+      // no-inline functions as functions which may be inlined cannot
+      // meaningfully return via assembly.
+      bool CheckReturnViaAsm = CheckReturn &&
+                               F->hasFnAttribute(Attribute::Naked) &&
+                               F->hasFnAttribute(Attribute::NoInline);
+
+      if (!CheckUnwind && !CheckReturn)
+        continue;
+
+      for (const BasicBlock &BB : *F) {
+        const Instruction *TI = BB.getTerminator();
+        if (CheckUnwind && TI->mayThrow()) {
+          SCCMightUnwind = true;
+        } else if (CheckReturn && isa<ReturnInst>(TI)) {
+          SCCMightReturn = true;
+        }
+
+        for (const Instruction &I : BB) {
+          if ((!CheckUnwind || SCCMightUnwind) &&
+              (!CheckReturnViaAsm || SCCMightReturn))
+            break;
+
+          // Check to see if this function performs an unwind or calls an
+          // unwinding function.
+          if (CheckUnwind && !SCCMightUnwind && I.mayThrow()) {
+            bool InstMightUnwind = true;
+            if (const auto *CI = dyn_cast<CallInst>(&I)) {
+              if (Function *Callee = CI->getCalledFunction()) {
+                CallGraphNode *CalleeNode = CG[Callee];
+                // If the callee is outside our current SCC then we may throw
+                // because it might.  If it is inside, do nothing.
+                if (SCCNodes.count(CalleeNode) > 0)
+                  InstMightUnwind = false;
+              }
+            }
+            SCCMightUnwind |= InstMightUnwind;
+          }
+          if (CheckReturnViaAsm && !SCCMightReturn)
+            if (auto ICS = ImmutableCallSite(&I))
+              if (const auto *IA = dyn_cast<InlineAsm>(ICS.getCalledValue()))
+                if (IA->hasSideEffects())
+                  SCCMightReturn = true;
+        }
+
+        if (SCCMightUnwind && SCCMightReturn)
+          break;
+      }
+    }
+  }
+
+  // If the SCC doesn't unwind or doesn't throw, note this fact.
+  if (!SCCMightUnwind || !SCCMightReturn)
+    for (CallGraphNode *I : SCC) {
+      Function *F = I->getFunction();
+
+      if (!SCCMightUnwind && !F->hasFnAttribute(Attribute::NoUnwind)) {
+        F->addFnAttr(Attribute::NoUnwind);
+        MadeChange = true;
+      }
+
+      if (!SCCMightReturn && !F->hasFnAttribute(Attribute::NoReturn)) {
+        F->addFnAttr(Attribute::NoReturn);
+        MadeChange = true;
+      }
+    }
+
+  for (CallGraphNode *I : SCC) {
+    // Convert any invoke instructions to non-throwing functions in this node
+    // into call instructions with a branch.  This makes the exception blocks
+    // dead.
+    if (Function *F = I->getFunction())
+      MadeChange |= SimplifyFunction(F, CG);
+  }
+
+  return MadeChange;
+}
+
+
+bool PruneEH::runOnSCC(CallGraphSCC &SCC) {
+  if (skipSCC(SCC))
+    return false;
+  CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
+  return runImpl(SCC, CG);
+}
+
+
+// SimplifyFunction - Given information about callees, simplify the specified
+// function if we have invokes to non-unwinding functions or code after calls to
+// no-return functions.
+static bool SimplifyFunction(Function *F, CallGraph &CG) {
+  bool MadeChange = false;
+  for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
+    if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()))
+      if (II->doesNotThrow() && canSimplifyInvokeNoUnwind(F)) {
+        BasicBlock *UnwindBlock = II->getUnwindDest();
+        removeUnwindEdge(&*BB);
+
+        // If the unwind block is now dead, nuke it.
+        if (pred_empty(UnwindBlock))
+          DeleteBasicBlock(UnwindBlock, CG);  // Delete the new BB.
+
+        ++NumRemoved;
+        MadeChange = true;
+      }
+
+    for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; )
+      if (CallInst *CI = dyn_cast<CallInst>(I++))
+        if (CI->doesNotReturn() && !CI->isMustTailCall() &&
+            !isa<UnreachableInst>(I)) {
+          // This call calls a function that cannot return.  Insert an
+          // unreachable instruction after it and simplify the code.  Do this
+          // by splitting the BB, adding the unreachable, then deleting the
+          // new BB.
+          BasicBlock *New = BB->splitBasicBlock(I);
+
+          // Remove the uncond branch and add an unreachable.
+          BB->getInstList().pop_back();
+          new UnreachableInst(BB->getContext(), &*BB);
+
+          DeleteBasicBlock(New, CG);  // Delete the new BB.
+          MadeChange = true;
+          ++NumUnreach;
+          break;
+        }
+  }
+
+  return MadeChange;
+}
+
+/// DeleteBasicBlock - remove the specified basic block from the program,
+/// updating the callgraph to reflect any now-obsolete edges due to calls that
+/// exist in the BB.
+static void DeleteBasicBlock(BasicBlock *BB, CallGraph &CG) {
+  assert(pred_empty(BB) && "BB is not dead!");
+
+  Instruction *TokenInst = nullptr;
+
+  CallGraphNode *CGN = CG[BB->getParent()];
+  for (BasicBlock::iterator I = BB->end(), E = BB->begin(); I != E; ) {
+    --I;
+
+    if (I->getType()->isTokenTy()) {
+      TokenInst = &*I;
+      break;
+    }
+
+    if (auto *Call = dyn_cast<CallBase>(&*I)) {
+      const Function *Callee = Call->getCalledFunction();
+      if (!Callee || !Intrinsic::isLeaf(Callee->getIntrinsicID()))
+        CGN->removeCallEdgeFor(*Call);
+      else if (!Callee->isIntrinsic())
+        CGN->removeCallEdgeFor(*Call);
+    }
+
+    if (!I->use_empty())
+      I->replaceAllUsesWith(UndefValue::get(I->getType()));
+  }
+
+  if (TokenInst) {
+    if (!TokenInst->isTerminator())
+      changeToUnreachable(TokenInst->getNextNode(), /*UseLLVMTrap=*/false);
+  } else {
+    // Get the list of successors of this block.
+    std::vector<BasicBlock *> Succs(succ_begin(BB), succ_end(BB));
+
+    for (unsigned i = 0, e = Succs.size(); i != e; ++i)
+      Succs[i]->removePredecessor(BB);
+
+    BB->eraseFromParent();
+  }
+}