ARM: Use a Handle to track SDNodes in case they're CSE'd. NFC

The code here is recursively Select-ing a new Node to avoid issues
where N is CSE'd during replaceDAGValue and stops being valid. We can
accomplish the same goal in a more principled way by using a
HandleSDNode.

This is essentially a less dodgy fix for PR25733 than the original
attempt back in r255120.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268590 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index ac1b7d474cb607a75619b5b55031b9641786a546..41cd6eaf74c86e1c834f6d63a9eb5bd63bc43c90 100644 (file)
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -551,11 +551,9 @@ bool ARMDAGToDAGISel::SelectImmShifterOperand(SDValue N,
     unsigned PowerOfTwo = 0;
     SDValue NewMulConst;
     if (canExtractShiftFromMul(N, 31, PowerOfTwo, NewMulConst)) {
-      BaseReg = SDValue(Select(CurDAG->getNode(ISD::MUL, SDLoc(N), MVT::i32,
-                                               N.getOperand(0), NewMulConst)
-                                   .getNode()),
-                        0);
+      HandleSDNode Handle(N);
       replaceDAGValue(N.getOperand(1), NewMulConst);
+      BaseReg = Handle.getValue();
       Opc = CurDAG->getTargetConstant(ARM_AM::getSORegOpc(ARM_AM::lsl,
                                                           PowerOfTwo),
                                       SDLoc(N), MVT::i32);