Clean up doxygen comments in FunctionAttrs, promoting some non-doxygen
[oota-llvm.git] / lib / Transforms / InstCombine / InstructionCombining.cpp
index b0604534150e6bfb621b085db99969ea191d6e28..badf2d6a6328c5fc2ec382f4a60c5c09bcf8a568 100644 (file)
@@ -42,6 +42,7 @@
 #include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/CFG.h"
 #include "llvm/Analysis/ConstantFolding.h"
+#include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LibCallSemantics.h"
 #include "llvm/Analysis/LoopInfo.h"
@@ -452,6 +453,7 @@ static Value *tryFactorization(InstCombiner::BuilderTy *Builder,
   if (!A || !C || !B || !D)
     return nullptr;
 
+  Value *V = nullptr;
   Value *SimplifiedInst = nullptr;
   Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
   Instruction::BinaryOps TopLevelOpcode = I.getOpcode();
@@ -468,7 +470,7 @@ static Value *tryFactorization(InstCombiner::BuilderTy *Builder,
         std::swap(C, D);
       // Consider forming "A op' (B op D)".
       // If "B op D" simplifies then it can be formed with no cost.
-      Value *V = SimplifyBinOp(TopLevelOpcode, B, D, DL);
+      V = SimplifyBinOp(TopLevelOpcode, B, D, DL);
       // If "B op D" doesn't simplify then only go on if both of the existing
       // operations "A op' B" and "C op' D" will be zapped as no longer used.
       if (!V && LHS->hasOneUse() && RHS->hasOneUse())
@@ -487,7 +489,7 @@ static Value *tryFactorization(InstCombiner::BuilderTy *Builder,
         std::swap(C, D);
       // Consider forming "(A op C) op' B".
       // If "A op C" simplifies then it can be formed with no cost.
-      Value *V = SimplifyBinOp(TopLevelOpcode, A, C, DL);
+      V = SimplifyBinOp(TopLevelOpcode, A, C, DL);
 
       // If "A op C" doesn't simplify then only go on if both of the existing
       // operations "A op' B" and "C op' D" will be zapped as no longer used.
@@ -517,7 +519,19 @@ static Value *tryFactorization(InstCombiner::BuilderTy *Builder,
         if (BinaryOperator *Op1 = dyn_cast<BinaryOperator>(RHS))
           if (isa<OverflowingBinaryOperator>(Op1))
             HasNSW &= Op1->hasNoSignedWrap();
-        BO->setHasNoSignedWrap(HasNSW);
+
+        // We can propagate 'nsw' if we know that
+        //  %Y = mul nsw i16 %X, C
+        //  %Z = add nsw i16 %Y, %X
+        // =>
+        //  %Z = mul nsw i16 %X, C+1
+        //
+        // iff C+1 isn't INT_MIN
+        const APInt *CInt;
+        if (TopLevelOpcode == Instruction::Add &&
+            InnerOpcode == Instruction::Mul)
+          if (match(V, m_APInt(CInt)) && !CInt->isMinSignedValue())
+            BO->setHasNoSignedWrap(HasNSW);
       }
     }
   }
@@ -610,6 +624,33 @@ Value *InstCombiner::SimplifyUsingDistributiveLaws(BinaryOperator &I) {
       }
   }
 
+  // (op (select (a, c, b)), (select (a, d, b))) -> (select (a, (op c, d), 0))
+  // (op (select (a, b, c)), (select (a, b, d))) -> (select (a, 0, (op c, d)))
+  if (auto *SI0 = dyn_cast<SelectInst>(LHS)) {
+    if (auto *SI1 = dyn_cast<SelectInst>(RHS)) {
+      if (SI0->getCondition() == SI1->getCondition()) {
+        Value *SI = nullptr;
+        if (Value *V = SimplifyBinOp(TopLevelOpcode, SI0->getFalseValue(),
+                                     SI1->getFalseValue(), DL, TLI, DT, AC))
+          SI = Builder->CreateSelect(SI0->getCondition(),
+                                     Builder->CreateBinOp(TopLevelOpcode,
+                                                          SI0->getTrueValue(),
+                                                          SI1->getTrueValue()),
+                                     V);
+        if (Value *V = SimplifyBinOp(TopLevelOpcode, SI0->getTrueValue(),
+                                     SI1->getTrueValue(), DL, TLI, DT, AC))
+          SI = Builder->CreateSelect(
+              SI0->getCondition(), V,
+              Builder->CreateBinOp(TopLevelOpcode, SI0->getFalseValue(),
+                                   SI1->getFalseValue()));
+        if (SI) {
+          SI->takeName(&I);
+          return SI;
+        }
+      }
+    }
+  }
+
   return nullptr;
 }
 
@@ -806,7 +847,7 @@ Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I) {
   NewPN->takeName(PN);
 
   // If we are going to have to insert a new computation, do so right before the
-  // predecessors terminator.
+  // predecessor's terminator.
   if (NonConstBB)
     Builder->SetInsertPoint(NonConstBB->getTerminator());
 
@@ -1830,7 +1871,7 @@ isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users,
 
       case Instruction::BitCast:
       case Instruction::GetElementPtr:
-        Users.push_back(I);
+        Users.emplace_back(I);
         Worklist.push_back(I);
         continue;
 
@@ -1839,7 +1880,7 @@ isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users,
         // We can fold eq/ne comparisons with null to false/true, respectively.
         if (!ICI->isEquality() || !isa<ConstantPointerNull>(ICI->getOperand(1)))
           return false;
-        Users.push_back(I);
+        Users.emplace_back(I);
         continue;
       }
 
@@ -1865,13 +1906,13 @@ isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users,
           case Intrinsic::lifetime_start:
           case Intrinsic::lifetime_end:
           case Intrinsic::objectsize:
-            Users.push_back(I);
+            Users.emplace_back(I);
             continue;
           }
         }
 
         if (isFreeCall(I, TLI)) {
-          Users.push_back(I);
+          Users.emplace_back(I);
           continue;
         }
         return false;
@@ -1880,7 +1921,7 @@ isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users,
         StoreInst *SI = cast<StoreInst>(I);
         if (SI->isVolatile() || SI->getPointerOperand() != PI)
           return false;
-        Users.push_back(I);
+        Users.emplace_back(I);
         continue;
       }
       }
@@ -2112,7 +2153,7 @@ Instruction *InstCombiner::visitSwitchInst(SwitchInst &SI) {
 
   // Truncate the condition operand if the new type is equal to or larger than
   // the largest legal integer type. We need to be conservative here since
-  // x86 generates redundant zero-extenstion instructions if the operand is
+  // x86 generates redundant zero-extension instructions if the operand is
   // truncated to i8 or i16.
   bool TruncCond = false;
   if (NewWidth > 0 && BitWidth > NewWidth &&
@@ -2161,16 +2202,9 @@ Instruction *InstCombiner::visitExtractValueInst(ExtractValueInst &EV) {
   if (!EV.hasIndices())
     return ReplaceInstUsesWith(EV, Agg);
 
-  if (Constant *C = dyn_cast<Constant>(Agg)) {
-    if (Constant *C2 = C->getAggregateElement(*EV.idx_begin())) {
-      if (EV.getNumIndices() == 0)
-        return ReplaceInstUsesWith(EV, C2);
-      // Extract the remaining indices out of the constant indexed by the
-      // first index
-      return ExtractValueInst::Create(C2, EV.getIndices().slice(1));
-    }
-    return nullptr; // Can't handle other constants
-  }
+  if (Value *V =
+          SimplifyExtractValueInst(Agg, EV.getIndices(), DL, TLI, DT, AC))
+    return ReplaceInstUsesWith(EV, V);
 
   if (InsertValueInst *IV = dyn_cast<InsertValueInst>(Agg)) {
     // We're extracting from an insertvalue instruction, compare the indices
@@ -2340,7 +2374,8 @@ Instruction *InstCombiner::visitLandingPadInst(LandingPadInst &LI) {
   // The logic here should be correct for any real-world personality function.
   // However if that turns out not to be true, the offending logic can always
   // be conditioned on the personality function, like the catch-all logic is.
-  EHPersonality Personality = classifyEHPersonality(LI.getPersonalityFn());
+  EHPersonality Personality =
+      classifyEHPersonality(LI.getParent()->getParent()->getPersonalityFn());
 
   // Simplify the list of clauses, eg by removing repeated catch clauses
   // (these are often created by inlining).
@@ -2607,7 +2642,6 @@ Instruction *InstCombiner::visitLandingPadInst(LandingPadInst &LI) {
   // with a new one.
   if (MakeNewInstruction) {
     LandingPadInst *NLI = LandingPadInst::Create(LI.getType(),
-                                                 LI.getPersonalityFn(),
                                                  NewClauses.size());
     for (unsigned i = 0, e = NewClauses.size(); i != e; ++i)
       NLI->addClause(NewClauses[i]);
@@ -2639,7 +2673,7 @@ static bool TryToSinkInstruction(Instruction *I, BasicBlock *DestBlock) {
   assert(I->hasOneUse() && "Invariants didn't hold!");
 
   // Cannot move control-flow-involving, volatile loads, vaarg, etc.
-  if (isa<PHINode>(I) || isa<LandingPadInst>(I) || I->mayHaveSideEffects() ||
+  if (isa<PHINode>(I) || I->isEHPad() || I->mayHaveSideEffects() ||
       isa<TerminatorInst>(I))
     return false;
 
@@ -2678,7 +2712,8 @@ bool InstCombiner::run() {
     }
 
     // Instruction isn't dead, see if we can constant propagate it.
-    if (!I->use_empty() && isa<Constant>(I->getOperand(0))) {
+    if (!I->use_empty() &&
+        (I->getNumOperands() == 0 || isa<Constant>(I->getOperand(0)))) {
       if (Constant *C = ConstantFoldInstruction(I, DL, TLI)) {
         DEBUG(dbgs() << "IC: ConstFold to: " << *C << " from: " << *I << '\n');
 
@@ -2833,7 +2868,8 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB, const DataLayout &DL,
       }
 
       // ConstantProp instruction if trivially constant.
-      if (!Inst->use_empty() && isa<Constant>(Inst->getOperand(0)))
+      if (!Inst->use_empty() &&
+          (Inst->getNumOperands() == 0 || isa<Constant>(Inst->getOperand(0))))
         if (Constant *C = ConstantFoldInstruction(Inst, DL, TLI)) {
           DEBUG(dbgs() << "IC: ConstFold to: " << *C << " from: "
                        << *Inst << '\n');
@@ -2892,8 +2928,8 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB, const DataLayout &DL,
       }
     }
 
-    for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
-      Worklist.push_back(TI->getSuccessor(i));
+    for (BasicBlock *SuccBB : TI->successors())
+      Worklist.push_back(SuccBB);
   } while (!Worklist.empty());
 
   // Once we've found all of the instructions to add to instcombine's worklist,
@@ -2940,7 +2976,7 @@ static bool prepareICWorklistFromFunction(Function &F, const DataLayout &DL,
       Instruction *Inst = --I;
       if (!Inst->use_empty())
         Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
-      if (isa<LandingPadInst>(Inst)) {
+      if (Inst->isEHPad()) {
         EndInst = Inst;
         continue;
       }
@@ -2957,10 +2993,9 @@ static bool prepareICWorklistFromFunction(Function &F, const DataLayout &DL,
 
 static bool
 combineInstructionsOverFunction(Function &F, InstCombineWorklist &Worklist,
-                                AssumptionCache &AC, TargetLibraryInfo &TLI,
-                                DominatorTree &DT, LoopInfo *LI = nullptr) {
-  // Minimizing size?
-  bool MinimizeSize = F.hasFnAttribute(Attribute::MinSize);
+                                AliasAnalysis *AA, AssumptionCache &AC,
+                                TargetLibraryInfo &TLI, DominatorTree &DT,
+                                LoopInfo *LI = nullptr) {
   auto &DL = F.getParent()->getDataLayout();
 
   /// Builder - This is an IRBuilder that automatically inserts new
@@ -2983,7 +3018,8 @@ combineInstructionsOverFunction(Function &F, InstCombineWorklist &Worklist,
     if (prepareICWorklistFromFunction(F, DL, &TLI, Worklist))
       Changed = true;
 
-    InstCombiner IC(Worklist, &Builder, MinimizeSize, &AC, &TLI, &DT, DL, LI);
+    InstCombiner IC(Worklist, &Builder, F.optForMinSize(),
+                    AA, &AC, &TLI, &DT, DL, LI);
     if (IC.run())
       Changed = true;
 
@@ -3002,7 +3038,8 @@ PreservedAnalyses InstCombinePass::run(Function &F,
 
   auto *LI = AM->getCachedResult<LoopAnalysis>(F);
 
-  if (!combineInstructionsOverFunction(F, Worklist, AC, TLI, DT, LI))
+  // FIXME: The AliasAnalysis is not yet supported in the new pass manager
+  if (!combineInstructionsOverFunction(F, Worklist, nullptr, AC, TLI, DT, LI))
     // No changes, all analyses are preserved.
     return PreservedAnalyses::all();
 
@@ -3035,10 +3072,12 @@ public:
 
 void InstructionCombiningPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesCFG();
+  AU.addRequired<AAResultsWrapperPass>();
   AU.addRequired<AssumptionCacheTracker>();
   AU.addRequired<TargetLibraryInfoWrapperPass>();
   AU.addRequired<DominatorTreeWrapperPass>();
   AU.addPreserved<DominatorTreeWrapperPass>();
+  AU.addPreserved<GlobalsAAWrapperPass>();
 }
 
 bool InstructionCombiningPass::runOnFunction(Function &F) {
@@ -3046,6 +3085,7 @@ bool InstructionCombiningPass::runOnFunction(Function &F) {
     return false;
 
   // Required analyses.
+  auto AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
   auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
   auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
   auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
@@ -3054,7 +3094,7 @@ bool InstructionCombiningPass::runOnFunction(Function &F) {
   auto *LIWP = getAnalysisIfAvailable<LoopInfoWrapperPass>();
   auto *LI = LIWP ? &LIWP->getLoopInfo() : nullptr;
 
-  return combineInstructionsOverFunction(F, Worklist, AC, TLI, DT, LI);
+  return combineInstructionsOverFunction(F, Worklist, AA, AC, TLI, DT, LI);
 }
 
 char InstructionCombiningPass::ID = 0;
@@ -3063,6 +3103,8 @@ INITIALIZE_PASS_BEGIN(InstructionCombiningPass, "instcombine",
 INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)
 INITIALIZE_PASS_END(InstructionCombiningPass, "instcombine",
                     "Combine redundant instructions", false, false)