Some ARM implementaions, e.g. A-series, does return stack prediction. That is,

the processor keeps a return addresses stack (RAS) which stores the address
and the instruction execution state of the instruction after a function-call
type branch instruction.

Calling a "noreturn" function with normal call instructions (e.g. bl) can
corrupt RAS and causes 100% return misprediction so LLVM should use a
unconditional branch instead. i.e.
mov lr, pc
b _foo
The "mov lr, pc" is issued in order to get proper backtrace.

rdar://8979299


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151623 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 2 deletions

diff --git a/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index d18766a8e9..caf6df91ed 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -2311,8 +2311,10 @@ void DAGTypeLegalizer::ExpandIntRes_XMULO(SDNode *N,
   SDValue Func = DAG.getExternalSymbol(TLI.getLibcallName(LC), PtrVT);
   std::pair<SDValue, SDValue> CallInfo =
     TLI.LowerCallTo(Chain, RetTy, true, false, false, false,
-		    0, TLI.getLibcallCallingConv(LC), false,
-		    true, Func, Args, DAG, dl);
+		    0, TLI.getLibcallCallingConv(LC),
+                    /*isTailCall=*/false,
+		    /*doesNotReturn=*/false, /*isReturnValueUsed=*/true,
+                    Func, Args, DAG, dl);
 
   SplitInteger(CallInfo.first, Lo, Hi);
   SDValue Temp2 = DAG.getLoad(PtrVT, dl, CallInfo.second, Temp,