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diff --git a/contrib/llvm/lib/Transforms/Utils/SimplifyInstructions.cpp b/contrib/llvm/lib/Transforms/Utils/SimplifyInstructions.cpp
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+++ b/contrib/llvm/lib/Transforms/Utils/SimplifyInstructions.cpp
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+//===------ SimplifyInstructions.cpp - Remove redundant instructions ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is a utility pass used for testing the InstructionSimplify analysis.
+// The analysis is applied to every instruction, and if it simplifies then the
+// instruction is replaced by the simplification.  If you are looking for a pass
+// that performs serious instruction folding, use the instcombine pass instead.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/Utils/Local.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "instsimplify"
+
+STATISTIC(NumSimplified, "Number of redundant instructions removed");
+
+namespace {
+  struct InstSimplifier : public FunctionPass {
+    static char ID; // Pass identification, replacement for typeid
+    InstSimplifier() : FunctionPass(ID) {
+      initializeInstSimplifierPass(*PassRegistry::getPassRegistry());
+    }
+
+    void getAnalysisUsage(AnalysisUsage &AU) const override {
+      AU.setPreservesCFG();
+      AU.addRequired<AssumptionCacheTracker>();
+      AU.addRequired<TargetLibraryInfoWrapperPass>();
+    }
+
+    /// runOnFunction - Remove instructions that simplify.
+    bool runOnFunction(Function &F) override {
+      const DominatorTreeWrapperPass *DTWP =
+          getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+      const DominatorTree *DT = DTWP ? &DTWP->getDomTree() : nullptr;
+      const DataLayout &DL = F.getParent()->getDataLayout();
+      const TargetLibraryInfo *TLI =
+          &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+      AssumptionCache *AC =
+          &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
+      SmallPtrSet<const Instruction*, 8> S1, S2, *ToSimplify = &S1, *Next = &S2;
+      bool Changed = false;
+
+      do {
+        for (BasicBlock *BB : depth_first(&F.getEntryBlock()))
+          // Here be subtlety: the iterator must be incremented before the loop
+          // body (not sure why), so a range-for loop won't work here.
+          for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) {
+            Instruction *I = &*BI++;
+            // The first time through the loop ToSimplify is empty and we try to
+            // simplify all instructions.  On later iterations ToSimplify is not
+            // empty and we only bother simplifying instructions that are in it.
+            if (!ToSimplify->empty() && !ToSimplify->count(I))
+              continue;
+            // Don't waste time simplifying unused instructions.
+            if (!I->use_empty())
+              if (Value *V = SimplifyInstruction(I, DL, TLI, DT, AC)) {
+                // Mark all uses for resimplification next time round the loop.
+                for (User *U : I->users())
+                  Next->insert(cast<Instruction>(U));
+                I->replaceAllUsesWith(V);
+                ++NumSimplified;
+                Changed = true;
+              }
+            bool res = RecursivelyDeleteTriviallyDeadInstructions(I, TLI);
+            if (res)  {
+              // RecursivelyDeleteTriviallyDeadInstruction can remove
+              // more than one instruction, so simply incrementing the
+              // iterator does not work. When instructions get deleted
+              // re-iterate instead.
+              BI = BB->begin(); BE = BB->end();
+              Changed |= res;
+            }
+          }
+
+        // Place the list of instructions to simplify on the next loop iteration
+        // into ToSimplify.
+        std::swap(ToSimplify, Next);
+        Next->clear();
+      } while (!ToSimplify->empty());
+
+      return Changed;
+    }
+  };
+}
+
+char InstSimplifier::ID = 0;
+INITIALIZE_PASS_BEGIN(InstSimplifier, "instsimplify",
+                      "Remove redundant instructions", false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
+INITIALIZE_PASS_END(InstSimplifier, "instsimplify",
+                    "Remove redundant instructions", false, false)
+char &llvm::InstructionSimplifierID = InstSimplifier::ID;
+
+// Public interface to the simplify instructions pass.
+FunctionPass *llvm::createInstructionSimplifierPass() {
+  return new InstSimplifier();
+}