PR16726: extend rol/ror matching

[oota-llvm.git] / lib / CodeGen / SelectionDAG / DAGCombiner.cpp

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 0eecd39d247303e902d8c1cf973e535eb8a1c84f..a565da5299c853f86393e619aafee842608d4103 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -3341,6 +3341,7 @@ SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, SDLoc DL) {
   unsigned OpSizeInBits = VT.getSizeInBits();
   SDValue LHSShiftArg = LHSShift.getOperand(0);
   SDValue LHSShiftAmt = LHSShift.getOperand(1);
+  SDValue RHSShiftArg = RHSShift.getOperand(0);
   SDValue RHSShiftAmt = RHSShift.getOperand(1);
 
   // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1)
@@ -3420,10 +3421,27 @@ SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, SDLoc DL) {
       //   (rotr x, (sub 32, y))
       if (ConstantSDNode *SUBC =
             dyn_cast<ConstantSDNode>(RExtOp0.getOperand(0)))
-        if (SUBC->getAPIntValue() == OpSizeInBits)
+        if (SUBC->getAPIntValue() == OpSizeInBits) {
           return DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, DL, VT,
                              LHSShiftArg,
                              HasROTL ? LHSShiftAmt : RHSShiftAmt).getNode();
+        } else if (LHSShiftArg.getOpcode() == ISD::ZERO_EXTEND ||
+                 LHSShiftArg.getOpcode() == ISD::ANY_EXTEND) {
+          // fold (or (shl (*ext x), (*ext y)),
+          //          (srl (*ext x), (*ext (sub 32, y)))) ->
+          //   (*ext (rotl x, y))
+          // fold (or (shl (*ext x), (*ext y)),
+          //          (srl (*ext x), (*ext (sub 32, y)))) ->
+          //   (*ext (rotr x, (sub 32, y)))
+          SDValue LArgExtOp0 = LHSShiftArg.getOperand(0);
+          EVT LArgVT = LArgExtOp0.getValueType();
+          if (LArgVT.getSizeInBits() == SUBC->getAPIntValue()) {
+            SDValue V = DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, DL, LArgVT,
+                             LArgExtOp0,
+                             HasROTL ? LHSShiftAmt : RHSShiftAmt);
+            return DAG.getNode(LHSShiftArg.getOpcode(), DL, VT, V).getNode();
+          }
+        }
     } else if (LExtOp0.getOpcode() == ISD::SUB &&
                RExtOp0 == LExtOp0.getOperand(1)) {
       // fold (or (shl x, (*ext (sub 32, y))), (srl x, (*ext y))) ->
@@ -3432,10 +3450,27 @@ SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, SDLoc DL) {
       //   (rotl x, (sub 32, y))
       if (ConstantSDNode *SUBC =
             dyn_cast<ConstantSDNode>(LExtOp0.getOperand(0)))
-        if (SUBC->getAPIntValue() == OpSizeInBits)
+        if (SUBC->getAPIntValue() == OpSizeInBits) {
           return DAG.getNode(HasROTR ? ISD::ROTR : ISD::ROTL, DL, VT,
                              LHSShiftArg,
                              HasROTR ? RHSShiftAmt : LHSShiftAmt).getNode();
+        } else if (RHSShiftArg.getOpcode() == ISD::ZERO_EXTEND ||
+                 RHSShiftArg.getOpcode() == ISD::ANY_EXTEND) {
+          // fold (or (shl (*ext x), (*ext (sub 32, y))),
+          //          (srl (*ext x), (*ext y))) ->
+          //   (*ext (rotl x, y))
+          // fold (or (shl (*ext x), (*ext (sub 32, y))),
+          //          (srl (*ext x), (*ext y))) ->
+          //   (*ext (rotr x, (sub 32, y)))
+          SDValue RArgExtOp0 = RHSShiftArg.getOperand(0);
+          EVT RArgVT = RArgExtOp0.getValueType();
+          if (RArgVT.getSizeInBits() == SUBC->getAPIntValue()) {
+            SDValue V = DAG.getNode(HasROTR ? ISD::ROTR : ISD::ROTL, DL, RArgVT,
+                             RArgExtOp0,
+                             HasROTR ? RHSShiftAmt : LHSShiftAmt);
+            return DAG.getNode(RHSShiftArg.getOpcode(), DL, VT, V).getNode();
+          }
+        }
     }
   }