1 files changed, 65 insertions, 44 deletions

diff --git a/lib/Transforms/Utils/SimplifyInstructions.cpp b/lib/Transforms/Utils/SimplifyInstructions.cpp
index d5377f9a4c1f..df299067094f 100644
--- a/lib/Transforms/Utils/SimplifyInstructions.cpp
+++ b/lib/Transforms/Utils/SimplifyInstructions.cpp
@@ -14,7 +14,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/SimplifyInstructions.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
@@ -27,12 +27,60 @@
 #include "llvm/IR/Type.h"
 #include "llvm/Pass.h"
 #include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Scalar.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "instsimplify"
 
 STATISTIC(NumSimplified, "Number of redundant instructions removed");
 
+static bool runImpl(Function &F, const DominatorTree *DT, const TargetLibraryInfo *TLI,
+                    AssumptionCache *AC) {
+  const DataLayout &DL = F.getParent()->getDataLayout();
+  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;
+}
+
 namespace {
   struct InstSimplifier : public FunctionPass {
     static char ID; // Pass identification, replacement for typeid
@@ -48,56 +96,17 @@ namespace {
 
     /// runOnFunction - Remove instructions that simplify.
     bool runOnFunction(Function &F) override {
+      if (skipFunction(F))
+        return false;
+
       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;
+      return runImpl(F, DT, TLI, AC);
     }
   };
 }
@@ -115,3 +124,15 @@ char &llvm::InstructionSimplifierID = InstSimplifier::ID;
 FunctionPass *llvm::createInstructionSimplifierPass() {
   return new InstSimplifier();
 }
+
+PreservedAnalyses InstSimplifierPass::run(Function &F,
+                                      AnalysisManager<Function> &AM) {
+  auto *DT = AM.getCachedResult<DominatorTreeAnalysis>(F);
+  auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
+  auto &AC = AM.getResult<AssumptionAnalysis>(F);
+  bool Changed = runImpl(F, DT, &TLI, &AC);
+  if (!Changed)
+    return PreservedAnalyses::all();
+  // FIXME: This should also 'preserve the CFG'.
+  return PreservedAnalyses::none();
+}