Fix sext(setcc) -> select_cc using wrong type for setcc.

Also update the comment, since it actually produces a
select (setcc) instead of select_cc.

It was checking and using the setcc result type for the
type of the sext, instead of the type of the compared items.

In my problem case, the sext was to i32 and was used as the setcc type,
but the expected type was i64.

No test since I haven't been able to hit the problem with
this on any in-tree targets.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200249 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 9a64b71d947aa24b2b06c874b8a988bb0a1f8a90..1b0b2ef8979572d884a9ba0f9c04e6fa0a530628 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4901,7 +4901,7 @@ SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
       }
     }
 
-    // sext(setcc x, y, cc) -> (select_cc x, y, -1, 0, cc)
+    // sext(setcc x, y, cc) -> (select (setcc x, y, cc), -1, 0)
     unsigned ElementWidth = VT.getScalarType().getSizeInBits();
     SDValue NegOne =
       DAG.getConstant(APInt::getAllOnesValue(ElementWidth), VT);
@@ -4910,15 +4910,21 @@ SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
                        NegOne, DAG.getConstant(0, VT),
                        cast<CondCodeSDNode>(N0.getOperand(2))->get(), true);
     if (SCC.getNode()) return SCC;
-    if (!VT.isVector() &&
-        (!LegalOperations ||
-         TLI.isOperationLegal(ISD::SETCC, getSetCCResultType(VT)))) {
-      return DAG.getSelect(SDLoc(N), VT,
-                           DAG.getSetCC(SDLoc(N),
-                           getSetCCResultType(VT),
-                           N0.getOperand(0), N0.getOperand(1),
-                           cast<CondCodeSDNode>(N0.getOperand(2))->get()),
-                           NegOne, DAG.getConstant(0, VT));
+
+    if (!VT.isVector()) {
+      EVT SetCCVT = getSetCCResultType(N0.getOperand(0).getValueType());
+      if (!LegalOperations || TLI.isOperationLegal(ISD::SETCC, SetCCVT)) {
+        SDLoc DL(N);
+        ISD::CondCode CC = cast<CondCodeSDNode>(N0.getOperand(2))->get();
+        SDValue SetCC = DAG.getSetCC(DL,
+                                     SetCCVT,
+                                     N0.getOperand(0), N0.getOperand(1), CC);
+        EVT SelectVT = getSetCCResultType(VT);
+        return DAG.getSelect(DL, VT,
+                             DAG.getSExtOrTrunc(SetCC, DL, SelectVT),
+                             NegOne, DAG.getConstant(0, VT));
+
+      }
     }
   }