vendor/llvm/llvm-trunk-r321017

1 files changed, 46 insertions, 10 deletions

diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp
index 3d5cbfc93f2e..606bd8baccaa 100644
--- a/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -1,4 +1,4 @@
-//===-- BasicBlockUtils.cpp - BasicBlock Utilities -------------------------==//
+//===- BasicBlockUtils.cpp - BasicBlock Utilities --------------------------==//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -13,22 +13,36 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Twine.h"
 #include "llvm/Analysis/CFG.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/MemoryDependenceAnalysis.h"
-#include "llvm/IR/Constant.h"
-#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/CFG.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/InstrTypes.h"
+#include "llvm/IR/Instruction.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Type.h"
+#include "llvm/IR/User.h"
+#include "llvm/IR/Value.h"
 #include "llvm/IR/ValueHandle.h"
-#include "llvm/Support/ErrorHandling.h"
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Support/Casting.h"
 #include "llvm/Transforms/Utils/Local.h"
-#include <algorithm>
+#include <cassert>
+#include <cstdint>
+#include <string>
+#include <utility>
+#include <vector>
+
 using namespace llvm;
 
 void llvm::DeleteDeadBlock(BasicBlock *BB) {
@@ -130,8 +144,16 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, DominatorTree *DT,
   }
 
   // Begin by getting rid of unneeded PHIs.
-  if (isa<PHINode>(BB->front()))
+  SmallVector<Value *, 4> IncomingValues;
+  if (isa<PHINode>(BB->front())) {
+    for (auto &I : *BB)
+      if (PHINode *PN = dyn_cast<PHINode>(&I)) {
+        if (PN->getIncomingValue(0) != PN)
+          IncomingValues.push_back(PN->getIncomingValue(0));
+      } else
+        break;
     FoldSingleEntryPHINodes(BB, MemDep);
+  }
 
   // Delete the unconditional branch from the predecessor...
   PredBB->getInstList().pop_back();
@@ -143,6 +165,21 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, DominatorTree *DT,
   // Move all definitions in the successor to the predecessor...
   PredBB->getInstList().splice(PredBB->end(), BB->getInstList());
 
+  // Eliminate duplicate dbg.values describing the entry PHI node post-splice.
+  for (auto *Incoming : IncomingValues) {
+    if (isa<Instruction>(Incoming)) {
+      SmallVector<DbgValueInst *, 2> DbgValues;
+      SmallDenseSet<std::pair<DILocalVariable *, DIExpression *>, 2>
+          DbgValueSet;
+      llvm::findDbgValues(DbgValues, Incoming);
+      for (auto &DVI : DbgValues) {
+        auto R = DbgValueSet.insert({DVI->getVariable(), DVI->getExpression()});
+        if (!R.second)
+          DVI->eraseFromParent();
+      }
+    }
+  }
+
   // Inherit predecessors name if it exists.
   if (!PredBB->hasName())
     PredBB->takeName(BB);
@@ -454,7 +491,7 @@ BasicBlock *llvm::SplitBlockPredecessors(BasicBlock *BB,
   // node becomes an incoming value for BB's phi node.  However, if the Preds
   // list is empty, we need to insert dummy entries into the PHI nodes in BB to
   // account for the newly created predecessor.
-  if (Preds.size() == 0) {
+  if (Preds.empty()) {
     // Insert dummy values as the incoming value.
     for (BasicBlock::iterator I = BB->begin(); isa<PHINode>(I); ++I)
       cast<PHINode>(I)->addIncoming(UndefValue::get(I->getType()), NewBB);
@@ -675,7 +712,6 @@ void llvm::SplitBlockAndInsertIfThenElse(Value *Cond, Instruction *SplitBefore,
   ReplaceInstWithInst(HeadOldTerm, HeadNewTerm);
 }
 
-
 Value *llvm::GetIfCondition(BasicBlock *BB, BasicBlock *&IfTrue,
                              BasicBlock *&IfFalse) {
   PHINode *SomePHI = dyn_cast<PHINode>(BB->begin());