add the popcount instruction and support this in the isel

the primary user of this will probably end up being find-first-set-bit/find-
last-set-bit, which i'll get around to...


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21860 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/IA64/IA64ISelPattern.cpp b/lib/Target/IA64/IA64ISelPattern.cpp
index 06be6ab..2d00c3b 100644
--- a/lib/Target/IA64/IA64ISelPattern.cpp
+++ b/lib/Target/IA64/IA64ISelPattern.cpp
@@ -90,7 +90,6 @@
       setOperationAction(ISD::FSQRT, MVT::f32, Expand);
 
       //IA64 has these, but they are not implemented
-      setOperationAction(ISD::CTPOP, MVT::i64  , Expand);
       setOperationAction(ISD::CTTZ , MVT::i64  , Expand);
       setOperationAction(ISD::CTLZ , MVT::i64  , Expand);
 
@@ -1600,6 +1599,12 @@
     return Result;
   }
 
+  case ISD::CTPOP: {
+    Tmp1 = SelectExpr(N.getOperand(0));
+    BuildMI(BB, IA64::POPCNT, 1, Result).addReg(Tmp1);
+    return Result;
+  }
+
   case ISD::SHL: {
     Tmp1 = SelectExpr(N.getOperand(0));
     if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.getOperand(1))) {