More replacing of  target-dependent intrinsics with target-indepdent 
intrinsics.  The second instruction(s) to be handled are the vector versions 
of count set bits (ctpop).

The changes here are to clang so that it generates a target independent 
vector ctpop when it sees an ARM dependent vector bits set count.  The changes 
in llvm are to match the target independent vector ctpop and in 
VMCore/AutoUpgrade.cpp to update any existing bc files containing ARM 
dependent vector pop counts with target-independent ctpops.  There are also 
changes to an existing test case in llvm for ARM vector count instructions and 
to a test for the bitcode upgrade.

<rdar://problem/11892519>

There is deliberately no test for the change to clang, as so far as I know, no
consensus has been reached regarding how to test neon instructions in clang;
q.v. <rdar://problem/8762292>

llvm-svn: 160410
diff --git a/llvm/lib/VMCore/AutoUpgrade.cpp b/llvm/lib/VMCore/AutoUpgrade.cpp
index 8febce1..f0de5c2 100644
--- a/llvm/lib/VMCore/AutoUpgrade.cpp
+++ b/llvm/lib/VMCore/AutoUpgrade.cpp
@@ -66,6 +66,11 @@
                                "llvm.ctlz." + Name.substr(14), F->getParent());
       return true;
     }
+    if (Name.startswith("arm.neon.vcnt")) {
+      NewFn = Intrinsic::getDeclaration(F->getParent(), Intrinsic::ctpop,
+                                        F->arg_begin()->getType());
+      return true;
+    }
     break;
   }
   case 'c': {
@@ -314,11 +319,16 @@
   case Intrinsic::arm_neon_vclz: {
     // Change name from llvm.arm.neon.vclz.* to llvm.ctlz.*
     CI->replaceAllUsesWith(Builder.CreateCall2(NewFn, CI->getArgOperand(0),
-                                               Builder.getFalse(), 
+                                               Builder.getFalse(),
                                                "llvm.ctlz." + Name.substr(14)));
     CI->eraseFromParent();
     return;
   }
+  case Intrinsic::ctpop: {
+    CI->replaceAllUsesWith(Builder.CreateCall(NewFn, CI->getArgOperand(0)));
+    CI->eraseFromParent();
+    return;
+  }
 
   case Intrinsic::x86_xop_vfrcz_ss:
   case Intrinsic::x86_xop_vfrcz_sd: