Import LLVM 6.0.1 release including clang, lld and lldb.

"where is the kaboom?" deraadt@

1 files changed, 55 insertions, 21 deletions

diff --git a/gnu/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/gnu/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index 3d5cbfc93f2..8f59913e14b 100644
--- a/gnu/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/gnu/llvm/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) {
@@ -80,9 +94,8 @@ bool llvm::DeleteDeadPHIs(BasicBlock *BB, const TargetLibraryInfo *TLI) {
   // Recursively deleting a PHI may cause multiple PHIs to be deleted
   // or RAUW'd undef, so use an array of WeakTrackingVH for the PHIs to delete.
   SmallVector<WeakTrackingVH, 8> PHIs;
-  for (BasicBlock::iterator I = BB->begin();
-       PHINode *PN = dyn_cast<PHINode>(I); ++I)
-    PHIs.push_back(PN);
+  for (PHINode &PN : BB->phis())
+    PHIs.push_back(&PN);
 
   bool Changed = false;
   for (unsigned i = 0, e = PHIs.size(); i != e; ++i)
@@ -120,18 +133,19 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, DominatorTree *DT,
   if (!OnlySucc) return false;
 
   // Can't merge if there is PHI loop.
-  for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE; ++BI) {
-    if (PHINode *PN = dyn_cast<PHINode>(BI)) {
-      for (Value *IncValue : PN->incoming_values())
-        if (IncValue == PN)
-          return false;
-    } else
-      break;
-  }
+  for (PHINode &PN : BB->phis())
+    for (Value *IncValue : PN.incoming_values())
+      if (IncValue == &PN)
+        return false;
 
   // Begin by getting rid of unneeded PHIs.
-  if (isa<PHINode>(BB->front()))
+  SmallVector<Value *, 4> IncomingValues;
+  if (isa<PHINode>(BB->front())) {
+    for (PHINode &PN : BB->phis())
+      if (PN.getIncomingValue(0) != &PN)
+        IncomingValues.push_back(PN.getIncomingValue(0));
     FoldSingleEntryPHINodes(BB, MemDep);
+  }
 
   // Delete the unconditional branch from the predecessor...
   PredBB->getInstList().pop_back();
@@ -143,6 +157,21 @@ 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);
@@ -294,6 +323,12 @@ static void UpdateAnalysisInformation(BasicBlock *OldBB, BasicBlock *NewBB,
   bool IsLoopEntry = !!L;
   bool SplitMakesNewLoopHeader = false;
   for (BasicBlock *Pred : Preds) {
+    // Preds that are not reachable from entry should not be used to identify if
+    // OldBB is a loop entry or if SplitMakesNewLoopHeader. Unreachable blocks
+    // are not within any loops, so we incorrectly mark SplitMakesNewLoopHeader
+    // as true and make the NewBB the header of some loop. This breaks LI.
+    if (!DT->isReachableFromEntry(Pred))
+      continue;
     // If we need to preserve LCSSA, determine if any of the preds is a loop
     // exit.
     if (PreserveLCSSA)
@@ -454,7 +489,7 @@ 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 +710,6 @@ 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());