Update LLVM to r94309.

1 files changed, 23 insertions, 0 deletions

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 549527c..8883064 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1088,6 +1088,26 @@ SDValue DAGCombiner::visitADD(SDNode *N) {
     if (Result.getNode()) return Result;
   }
 
+  // fold (add x, shl(0 - y, n)) -> sub(x, shl(y, n))
+  if (N1.getOpcode() == ISD::SHL &&
+      N1.getOperand(0).getOpcode() == ISD::SUB)
+    if (ConstantSDNode *C =
+          dyn_cast<ConstantSDNode>(N1.getOperand(0).getOperand(0)))
+      if (C->getAPIntValue() == 0)
+        return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N0,
+                           DAG.getNode(ISD::SHL, N->getDebugLoc(), VT,
+                                       N1.getOperand(0).getOperand(1),
+                                       N1.getOperand(1)));
+  if (N0.getOpcode() == ISD::SHL &&
+      N0.getOperand(0).getOpcode() == ISD::SUB)
+    if (ConstantSDNode *C =
+          dyn_cast<ConstantSDNode>(N0.getOperand(0).getOperand(0)))
+      if (C->getAPIntValue() == 0)
+        return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT, N1,
+                           DAG.getNode(ISD::SHL, N->getDebugLoc(), VT,
+                                       N0.getOperand(0).getOperand(1),
+                                       N0.getOperand(1)));
+
   return SDValue();
 }
 
@@ -1176,6 +1196,9 @@ SDValue DAGCombiner::visitSUB(SDNode *N) {
   if (N1C)
     return DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0,
                        DAG.getConstant(-N1C->getAPIntValue(), VT));
+  // Canonicalize (sub -1, x) -> ~x, i.e. (xor x, -1)
+  if (N0C && N0C->isAllOnesValue())
+    return DAG.getNode(ISD::XOR, N->getDebugLoc(), VT, N1, N0);
   // fold (A+B)-A -> B
   if (N0.getOpcode() == ISD::ADD && N0.getOperand(0) == N1)
     return N0.getOperand(1);