Revert "Revert "Revert r248959, "[WinEH] Emit int3 after noreturn calls on Win64"""

[oota-llvm.git] / lib / Target / X86 / X86ISelLowering.cpp

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 9954b6c63cec6c6511cc26946e07c6e7d9a4fd92..fae877ab222ccccd2595c8edef534b1bf3ff5a78 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2951,20 +2951,6 @@ static SDValue getMOVL(SelectionDAG &DAG, SDLoc dl, EVT VT, SDValue V1,
   return DAG.getVectorShuffle(VT, dl, V1, V2, &Mask[0]);
 }
 
-/// Check if the fall through instruction after a call site is unreachable.
-/// FIXME: This will fail if there are interesting non-code generating IR
-/// instructions between the call and the unreachable (lifetime.end). In
-/// practice, this should be rare because optimizations like to delete non-call
-/// code before unreachable.
-static bool isCallFollowedByUnreachable(ImmutableCallSite CS) {
-  const Instruction *NextInst;
-  if (auto *II = dyn_cast<InvokeInst>(CS.getInstruction()))
-    NextInst = II->getNormalDest()->getFirstNonPHIOrDbg();
-  else
-    NextInst = CS.getInstruction()->getNextNode();
-  return isa<UnreachableInst>(NextInst);
-}
-
 SDValue
 X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
                              SmallVectorImpl<SDValue> &InVals) const {
@@ -3470,15 +3456,6 @@ X86TargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
     InFlag = Chain.getValue(1);
   }
 
-  if (Subtarget->isTargetWin64() && CLI.CS) {
-    // Look for a call followed by unreachable. On Win64, we need to ensure that
-    // the call does not accidentally fall through to something that looks like
-    // an epilogue. We do this by inserting a DEBUGTRAP, which lowers to int3,
-    // which is what MSVC emits after noreturn calls.
-    if (isCallFollowedByUnreachable(*CLI.CS))
-      Chain = DAG.getNode(ISD::DEBUGTRAP, dl, MVT::Other, Chain);
-  }
-
   // Handle result values, copying them out of physregs into vregs that we
   // return.
   return LowerCallResult(Chain, InFlag, CallConv, isVarArg,