Update LLVM to r104832.

1 files changed, 11 insertions, 3 deletions

diff --git a/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/lib/Transforms/Scalar/SimplifyCFGPass.cpp
index b621e8d..9744100 100644
--- a/lib/Transforms/Scalar/SimplifyCFGPass.cpp
+++ b/lib/Transforms/Scalar/SimplifyCFGPass.cpp
@@ -58,13 +58,20 @@ FunctionPass *llvm::createCFGSimplificationPass() {
 
 /// ChangeToUnreachable - Insert an unreachable instruction before the specified
 /// instruction, making it and the rest of the code in the block dead.
-static void ChangeToUnreachable(Instruction *I) {
+static void ChangeToUnreachable(Instruction *I, bool UseLLVMTrap) {
   BasicBlock *BB = I->getParent();
   // Loop over all of the successors, removing BB's entry from any PHI
   // nodes.
   for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
     (*SI)->removePredecessor(BB);
   
+  // Insert a call to llvm.trap right before this.  This turns the undefined
+  // behavior into a hard fail instead of falling through into random code.
+  if (UseLLVMTrap) {
+    Function *TrapFn =
+      Intrinsic::getDeclaration(BB->getParent()->getParent(), Intrinsic::trap);
+    CallInst::Create(TrapFn, "", I);
+  }
   new UnreachableInst(I->getContext(), I);
   
   // All instructions after this are dead.
@@ -118,7 +125,8 @@ static bool MarkAliveBlocks(BasicBlock *BB,
           // though.
           ++BBI;
           if (!isa<UnreachableInst>(BBI)) {
-            ChangeToUnreachable(BBI);
+            // Don't insert a call to llvm.trap right before the unreachable.
+            ChangeToUnreachable(BBI, false);
             Changed = true;
           }
           break;
@@ -134,7 +142,7 @@ static bool MarkAliveBlocks(BasicBlock *BB,
         if (isa<UndefValue>(Ptr) ||
             (isa<ConstantPointerNull>(Ptr) &&
              SI->getPointerAddressSpace() == 0)) {
-          ChangeToUnreachable(SI);
+          ChangeToUnreachable(SI, true);
           Changed = true;
           break;
         }