Move callseq_start above the call address load to allow load to be folded into the call node.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55292 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 5d8cb1c..09a30db 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1457,12 +1457,12 @@
SDValue X86TargetLowering::LowerCALL(SDValue Op, SelectionDAG &DAG) {
MachineFunction &MF = DAG.getMachineFunction();
- SDValue Chain = Op.getOperand(0);
+ SDValue Chain = Op.getOperand(0);
unsigned CC = cast<ConstantSDNode>(Op.getOperand(1))->getValue();
bool isVarArg = cast<ConstantSDNode>(Op.getOperand(2))->getValue() != 0;
bool IsTailCall = cast<ConstantSDNode>(Op.getOperand(3))->getValue() != 0
&& CC == CallingConv::Fast && PerformTailCallOpt;
- SDValue Callee = Op.getOperand(4);
+ SDValue Callee = Op.getOperand(4);
bool Is64Bit = Subtarget->is64Bit();
bool IsStructRet = CallIsStructReturn(Op);
@@ -1499,6 +1499,11 @@
MF.getInfo<X86MachineFunctionInfo>()->setTCReturnAddrDelta(FPDiff);
}
+ // If the address is a load, i.e. indirect function call, move callseq_start
+ // above the load. This makes it possible for the load to fold into the call.
+ if (Callee.Val == Chain.Val && ISD::isNormalLoad(Callee.Val) &&
+ Chain.hasOneUse() && Callee.hasOneUse())
+ Chain = Chain.getOperand(0);
Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(NumBytes));
SDValue RetAddrFrIdx;