Drop @llvm.annotation and @llvm.ptr.annotation intrinsics during codegen.

The intrinsic calls are dropped, but the annotated value is propagated.

Fixes PR 15253

Original patch by Zeng Bin!

llvm-svn: 182387

llvm/lib/CodeGen/IntrinsicLowering.cpp

@@ -453,6 +453,12 @@ void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
     CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1));
     break;
 
+  case Intrinsic::annotation:
+  case Intrinsic::ptr_annotation:
+    // Just drop the annotation, but forward the value
+    CI->replaceAllUsesWith(CI->getOperand(0));
+    break;
+
   case Intrinsic::var_annotation:
     break;   // Strip out annotate intrinsic