fold (aext (and (trunc x), cst)) -> (and x, cst).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30561 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 64014dcb05499732f1b12e5e9c6117aac4d10557..f093bf46f68037455798fe5cdbd0b1db77e08d5a 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1897,6 +1897,21 @@ SDOperand DAGCombiner::visitANY_EXTEND(SDNode *N) {
       return DAG.getNode(ISD::TRUNCATE, VT, TruncOp);
     return DAG.getNode(ISD::ANY_EXTEND, VT, TruncOp);
   }
+  
+  // fold (aext (and (trunc x), cst)) -> (and x, cst).
+  if (N0.getOpcode() == ISD::AND &&
+      N0.getOperand(0).getOpcode() == ISD::TRUNCATE &&
+      N0.getOperand(1).getOpcode() == ISD::Constant) {
+    SDOperand X = N0.getOperand(0).getOperand(0);
+    if (X.getValueType() < VT) {
+      X = DAG.getNode(ISD::ANY_EXTEND, VT, X);
+    } else if (X.getValueType() > VT) {
+      X = DAG.getNode(ISD::TRUNCATE, VT, X);
+    }
+    uint64_t Mask = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
+    return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT));
+  }
+  
   // fold (aext (load x)) -> (aext (truncate (extload x)))
   if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() &&
       (!AfterLegalize||TLI.isOperationLegal(ISD::EXTLOAD, N0.getValueType()))) {