ARM: don't use a deleted node as the BaseReg in complex pattern.

We mutated the DAG, which invalidated the node we were trying to use
as a base register. Sometimes we got away with it, but other times the
node really did get deleted before it was finished with.

Should fix PR25733

llvm-svn: 255120

1 files changed, 4 insertions, 1 deletions

diff --git a/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp b/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
index cd73021dfc6..024244092a3 100644
--- a/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -548,8 +548,11 @@ 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);
       replaceDAGValue(N.getOperand(1), NewMulConst);
-      BaseReg = N;
       Opc = CurDAG->getTargetConstant(ARM_AM::getSORegOpc(ARM_AM::lsl,
                                                           PowerOfTwo),
                                       SDLoc(N), MVT::i32);