[PPC] Add text for assert.

llvm-svn: 303940

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 7fde123..b90a5ee 100644 (file)
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -8296,7 +8296,7 @@ SDValue PPCTargetLowering::LowerINTRINSIC_VOID(SDValue Op,
   SDLoc DL(Op);
   switch (cast<ConstantSDNode>(Op.getOperand(ArgStart))->getZExtValue()) {
   case Intrinsic::ppc_cfence: {
-    assert(ArgStart == 1);
+    assert(ArgStart == 1 && "llvm.ppc.cfence must carry a chain argument.");
     assert(Subtarget.isPPC64() && "Only 64-bit is supported for now.");
     return SDValue(DAG.getMachineNode(PPC::CFENCE8, DL, MVT::Other,
                                       DAG.getNode(ISD::ANY_EXTEND, DL, MVT::i64,