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

[Matt Arsenault]

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.


http://llvm-reviews.chandlerc.com/D2558

Files:
  lib/CodeGen/SelectionDAG/DAGCombiner.cpp

Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4826,7 +4826,7 @@
       }
     }
 
-    // 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);
@@ -4835,15 +4835,21 @@
                        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));
+
+      }
     }
   }
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D2558.1.patch
Type: text/x-patch
Size: 1881 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20140115/b38e2b87/attachment.bin>