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, 2 insertions, 1 deletions

diff --git a/lib/Target/X86/X86SelectionDAGInfo.cpp b/lib/Target/X86/X86SelectionDAGInfo.cpp
index 6406bce311..9a04e352ab 100644
--- a/lib/Target/X86/X86SelectionDAGInfo.cpp
+++ b/lib/Target/X86/X86SelectionDAGInfo.cpp
@@ -65,7 +65,8 @@ X86SelectionDAGInfo::EmitTargetCodeForMemset(SelectionDAG &DAG, DebugLoc dl,
       std::pair<SDValue,SDValue> CallResult =
         TLI.LowerCallTo(Chain, Type::getVoidTy(*DAG.getContext()),
                         false, false, false, false,
-                        0, CallingConv::C, false, /*isReturnValueUsed=*/false,
+                        0, CallingConv::C, /*isTailCall=*/false,
+                        /*doesNotRet=*/false, /*isReturnValueUsed=*/false,
                         DAG.getExternalSymbol(bzeroEntry, IntPtr), Args,
                         DAG, dl);
       return CallResult.second;