VMCore/BasicBlock.cpp: Don't assume BasicBlock::iterator might end with a non-PHInode...

[oota-llvm.git] / lib / VMCore / BasicBlock.cpp

diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp
index 8ad53736c993f9c3c79e2737d1186bc8f50df76f..5fab1d39ae85ad275a865512a159dea8e0f1a105 100644 (file)
--- a/lib/VMCore/BasicBlock.cpp
+++ b/lib/VMCore/BasicBlock.cpp
@@ -53,7 +53,7 @@ BasicBlock::BasicBlock(LLVMContext &C, const Twine &Name, Function *NewParent,
   } else if (NewParent) {
     NewParent->getBasicBlockList().push_back(this);
   }
-  
+
   setName(Name);
 }
 
@@ -76,7 +76,7 @@ BasicBlock::~BasicBlock() {
       BA->destroyConstant();
     }
   }
-  
+
   assert(getParent() == 0 && "BasicBlock still linked into the program!");
   dropAllReferences();
   InstList.clear();
@@ -147,6 +147,26 @@ Instruction* BasicBlock::getFirstNonPHIOrDbg() {
   return &*i;
 }
 
+Instruction* BasicBlock::getFirstNonPHIOrDbgOrLifetime() {
+  // All valid basic blocks should have a terminator,
+  // which is not a PHINode. If we have an invalid basic
+  // block we'll get an assertion failure when dereferencing
+  // a past-the-end iterator.
+  BasicBlock::iterator i = begin();
+  for (;; ++i) {
+    if (isa<PHINode>(i) || isa<DbgInfoIntrinsic>(i))
+      continue;
+
+    const IntrinsicInst *II = dyn_cast<IntrinsicInst>(i);
+    if (!II)
+      break;
+    if (II->getIntrinsicID() != Intrinsic::lifetime_start &&
+        II->getIntrinsicID() != Intrinsic::lifetime_end)
+      break;
+  }
+  return &*i;
+}
+
 void BasicBlock::dropAllReferences() {
   for(iterator I = begin(), E = end(); I != E; ++I)
     I->dropAllReferences();
@@ -164,8 +184,8 @@ BasicBlock *BasicBlock::getSinglePredecessor() {
 
 /// getUniquePredecessor - If this basic block has a unique predecessor block,
 /// return the block, otherwise return a null pointer.
-/// Note that unique predecessor doesn't mean single edge, there can be 
-/// multiple edges from the unique predecessor to this block (for example 
+/// Note that unique predecessor doesn't mean single edge, there can be
+/// multiple edges from the unique predecessor to this block (for example
 /// a switch statement with multiple cases having the same destination).
 BasicBlock *BasicBlock::getUniquePredecessor() {
   pred_iterator PI = pred_begin(this), E = pred_end(this);
@@ -227,8 +247,8 @@ void BasicBlock::removePredecessor(BasicBlock *Pred,
 
       // If the PHI _HAD_ two uses, replace PHI node with its now *single* value
       if (max_idx == 2) {
-        if (PN->getOperand(0) != PN)
-          PN->replaceAllUsesWith(PN->getOperand(0));
+        if (PN->getIncomingValue(0) != PN)
+          PN->replaceAllUsesWith(PN->getIncomingValue(0));
         else
           // We are left with an infinite loop with no entries: kill the PHI.
           PN->replaceAllUsesWith(UndefValue::get(PN->getType()));
@@ -248,10 +268,11 @@ void BasicBlock::removePredecessor(BasicBlock *Pred,
       // If all incoming values to the Phi are the same, we can replace the Phi
       // with that value.
       Value* PNV = 0;
-      if (!DontDeleteUselessPHIs && (PNV = PN->hasConstantValue())) {
-        PN->replaceAllUsesWith(PNV);
-        PN->eraseFromParent();
-      }
+      if (!DontDeleteUselessPHIs && (PNV = PN->hasConstantValue()))
+        if (PNV != PN) {
+          PN->replaceAllUsesWith(PNV);
+          PN->eraseFromParent();
+        }
     }
   }
 }
@@ -307,3 +328,23 @@ BasicBlock *BasicBlock::splitBasicBlock(iterator I, const Twine &BBName) {
   return New;
 }
 
+void BasicBlock::replaceSuccessorsPhiUsesWith(BasicBlock *New) {
+  TerminatorInst *TI = getTerminator();
+  if (!TI)
+    // Cope with being called on a BasicBlock that doesn't have a terminator
+    // yet. Clang's CodeGenFunction::EmitReturnBlock() likes to do this.
+    return;
+  for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i) {
+    BasicBlock *Succ = TI->getSuccessor(i);
+    // N.B. Succ might not be a complete BasicBlock, so don't assume
+    // that it ends with a non-phi instruction.
+    for (iterator II = Succ->begin(), IE = Succ->end(); II != IE; ++II) {
+      PHINode *PN = dyn_cast<PHINode>(II);
+      if (!PN)
+        break;
+      int i;
+      while ((i = PN->getBasicBlockIndex(this)) >= 0)
+        PN->setIncomingBlock(i, New);
+    }
+  }
+}