Do not add unroll disable metadata after unrolling pass for loops with #pragma clang...

[oota-llvm.git] / lib / Transforms / Scalar / GVN.cpp

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index e7156fd6b601ab76079e58aad7ee727af605d9db..106eba099ca05504f06675b32a044cb99bcc5fcd 100644 (file)
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -19,6 +19,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/Hashing.h"
+#include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
@@ -214,7 +215,7 @@ Expression ValueTable::create_cmp_expression(unsigned Opcode,
 }
 
 Expression ValueTable::create_extractvalue_expression(ExtractValueInst *EI) {
-  assert(EI != 0 && "Not an ExtractValueInst?");
+  assert(EI && "Not an ExtractValueInst?");
   Expression e;
   e.type = EI->getType();
   e.opcode = 0;
@@ -1421,8 +1422,7 @@ void GVN::AnalyzeLoadAvailability(LoadInst *LI, LoadDepVect &Deps,
         // If this is a clobber and L is the first instruction in its block, then
         // we have the first instruction in the entry block.
         if (DepLI != LI && Address && DL) {
-          int Offset = AnalyzeLoadFromClobberingLoad(LI->getType(),
-                                                     LI->getPointerOperand(),
+          int Offset = AnalyzeLoadFromClobberingLoad(LI->getType(), Address,
                                                      DepLI, *DL);
 
           if (Offset != -1) {
@@ -1464,6 +1464,13 @@ void GVN::AnalyzeLoadAvailability(LoadInst *LI, LoadDepVect &Deps,
       continue;
     }
 
+    // Loading from calloc (which zero initializes memory) -> zero
+    if (isCallocLikeFn(DepInst, TLI)) {
+      ValuesPerBlock.push_back(AvailableValueInBlock::get(
+          DepBB, Constant::getNullValue(LI->getType())));
+      continue;
+    }
+
     if (StoreInst *S = dyn_cast<StoreInst>(DepInst)) {
       // Reject loads and stores that are to the same address but are of
       // different types if we have to.
@@ -1540,7 +1547,7 @@ bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
 
   // Check to see how many predecessors have the loaded value fully
   // available.
-  DenseMap<BasicBlock*, Value*> PredLoads;
+  MapVector<BasicBlock *, Value *> PredLoads;
   DenseMap<BasicBlock*, char> FullyAvailableBlocks;
   for (unsigned i = 0, e = ValuesPerBlock.size(); i != e; ++i)
     FullyAvailableBlocks[ValuesPerBlock[i].BB] = true;
@@ -1554,7 +1561,6 @@ bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
     if (IsValueFullyAvailableInBlock(Pred, FullyAvailableBlocks, 0)) {
       continue;
     }
-    PredLoads[Pred] = nullptr;
 
     if (Pred->getTerminator()->getNumSuccessors() != 1) {
       if (isa<IndirectBrInst>(Pred->getTerminator())) {
@@ -1571,11 +1577,14 @@ bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
       }
 
       CriticalEdgePred.push_back(Pred);
+    } else {
+      // Only add the predecessors that will not be split for now.
+      PredLoads[Pred] = nullptr;
     }
   }
 
   // Decide whether PRE is profitable for this load.
-  unsigned NumUnavailablePreds = PredLoads.size();
+  unsigned NumUnavailablePreds = PredLoads.size() + CriticalEdgePred.size();
   assert(NumUnavailablePreds != 0 &&
          "Fully available value should already be eliminated!");
 
@@ -1587,11 +1596,9 @@ bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
       return false;
 
   // Split critical edges, and update the unavailable predecessors accordingly.
-  for (SmallVectorImpl<BasicBlock *>::iterator I = CriticalEdgePred.begin(),
-         E = CriticalEdgePred.end(); I != E; I++) {
-    BasicBlock *OrigPred = *I;
+  for (BasicBlock *OrigPred : CriticalEdgePred) {
     BasicBlock *NewPred = splitCriticalEdges(OrigPred, LoadBB);
-    PredLoads.erase(OrigPred);
+    assert(!PredLoads.count(OrigPred) && "Split edges shouldn't be in map!");
     PredLoads[NewPred] = nullptr;
     DEBUG(dbgs() << "Split critical edge " << OrigPred->getName() << "->"
                  << LoadBB->getName() << '\n');
@@ -1600,9 +1607,8 @@ bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
   // Check if the load can safely be moved to all the unavailable predecessors.
   bool CanDoPRE = true;
   SmallVector<Instruction*, 8> NewInsts;
-  for (DenseMap<BasicBlock*, Value*>::iterator I = PredLoads.begin(),
-         E = PredLoads.end(); I != E; ++I) {
-    BasicBlock *UnavailablePred = I->first;
+  for (auto &PredLoad : PredLoads) {
+    BasicBlock *UnavailablePred = PredLoad.first;
 
     // Do PHI translation to get its value in the predecessor if necessary.  The
     // returned pointer (if non-null) is guaranteed to dominate UnavailablePred.
@@ -1624,7 +1630,7 @@ bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
       break;
     }
 
-    I->second = LoadPtr;
+    PredLoad.second = LoadPtr;
   }
 
   if (!CanDoPRE) {
@@ -1633,8 +1639,8 @@ bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
       if (MD) MD->removeInstruction(I);
       I->eraseFromParent();
     }
-    // HINT:Don't revert the edge-splitting as following transformation may 
-    // also need to split these critial edges.
+    // HINT: Don't revert the edge-splitting as following transformation may
+    // also need to split these critical edges.
     return !CriticalEdgePred.empty();
   }
 
@@ -1655,10 +1661,9 @@ bool GVN::PerformLoadPRE(LoadInst *LI, AvailValInBlkVect &ValuesPerBlock,
     VN.lookup_or_add(NewInsts[i]);
   }
 
-  for (DenseMap<BasicBlock*, Value*>::iterator I = PredLoads.begin(),
-         E = PredLoads.end(); I != E; ++I) {
-    BasicBlock *UnavailablePred = I->first;
-    Value *LoadPtr = I->second;
+  for (const auto &PredLoad : PredLoads) {
+    BasicBlock *UnavailablePred = PredLoad.first;
+    Value *LoadPtr = PredLoad.second;
 
     Instruction *NewLoad = new LoadInst(LoadPtr, LI->getName()+".pre", false,
                                         LI->getAlignment(),
@@ -1793,6 +1798,10 @@ static void patchReplacementInstruction(Instruction *I, Value *Repl) {
       case LLVMContext::MD_fpmath:
         ReplInst->setMetadata(Kind, MDNode::getMostGenericFPMath(IMD, ReplMD));
         break;
+      case LLVMContext::MD_invariant_load:
+        // Only set the !invariant.load if it is present in both instructions.
+        ReplInst->setMetadata(Kind, IMD);
+        break;
       }
     }
   }
@@ -1990,6 +1999,15 @@ bool GVN::processLoad(LoadInst *L) {
     }
   }
 
+  // If this load follows a calloc (which zero initializes memory),
+  // then the loaded value is zero
+  if (isCallocLikeFn(DepInst, TLI)) {
+    L->replaceAllUsesWith(Constant::getNullValue(L->getType()));
+    markInstructionForDeletion(L);
+    ++NumGVNLoad;
+    return true;
+  }
+
   return false;
 }