[DAGCombiner] Refactor code in visitShiftByConstant slightly to make it more readable. NFC

This changes the isShift variable to include the constant operand
check that was previously in the if statement.

While there fix an 80 column violation and an unnecessary use of
getNode. Also fix variable name capitalization.

llvm-svn: 361168

1 files changed, 12 insertions, 11 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index f88f084dd5e..799f95274b2 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -6618,19 +6618,20 @@ SDValue DAGCombiner::visitShiftByConstant(SDNode *N, ConstantSDNode *Amt) {
     return SDValue();
 
   // FIXME: disable this unless the input to the binop is a shift by a constant
-  // or is copy/select.Enable this in other cases when figure out it's exactly profitable.
-  SDNode *BinOpLHSVal = LHS->getOperand(0).getNode();
-  bool isShift = BinOpLHSVal->getOpcode() == ISD::SHL ||
-                 BinOpLHSVal->getOpcode() == ISD::SRA ||
-                 BinOpLHSVal->getOpcode() == ISD::SRL;
-  bool isCopyOrSelect = BinOpLHSVal->getOpcode() == ISD::CopyFromReg ||
-                        BinOpLHSVal->getOpcode() == ISD::SELECT;
-
-  if ((!isShift || !isa<ConstantSDNode>(BinOpLHSVal->getOperand(1))) &&
-      !isCopyOrSelect)
+  // or is copy/select. Enable this in other cases when figure out it's exactly
+  // profitable.
+  SDValue BinOpLHSVal = LHS->getOperand(0);
+  bool IsShiftByConstant = (BinOpLHSVal.getOpcode() == ISD::SHL ||
+                            BinOpLHSVal.getOpcode() == ISD::SRA ||
+                            BinOpLHSVal.getOpcode() == ISD::SRL) &&
+                           isa<ConstantSDNode>(BinOpLHSVal.getOperand(1));
+  bool IsCopyOrSelect = BinOpLHSVal.getOpcode() == ISD::CopyFromReg ||
+                        BinOpLHSVal.getOpcode() == ISD::SELECT;
+
+  if (!IsShiftByConstant && !IsCopyOrSelect)
     return SDValue();
 
-  if (isCopyOrSelect && N->hasOneUse())
+  if (IsCopyOrSelect && N->hasOneUse())
     return SDValue();
 
   EVT VT = N->getValueType(0);