[llvm] r268590 - ARM: Use a Handle to track SDNodes in case they're CSE'd. NFC

[Justin Bogner via llvm-commits]

Author: bogner
Date: Wed May  4 20:43:49 2016
New Revision: 268590

URL: http://llvm.org/viewvc/llvm-project?rev=268590&view=rev
Log:
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.

Modified:
    llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp

Modified: llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp?rev=268590&r1=268589&r2=268590&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMISelDAGToDAG.cpp Wed May  4 20:43:49 2016
@@ -551,11 +551,9 @@ bool ARMDAGToDAGISel::SelectImmShifterOp
     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);