Revert "[Sema] Add sizeof diagnostics for bzero"

This reverts commit r277787, which caused PR28870.

llvm-svn: 277830
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index c716394..12f3923 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -6179,15 +6179,13 @@
 
   // It is possible to have a non-standard definition of memset.  Validate
   // we have enough arguments, and if not, abort further checking.
-  unsigned ExpectedNumArgs =
-      (BId == Builtin::BIstrndup || Builtin::BIbzero ? 2 : 3);
+  unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3);
   if (Call->getNumArgs() < ExpectedNumArgs)
     return;
 
-  unsigned LastArg = (BId == Builtin::BImemset || BId == Builtin::BIbzero ||
+  unsigned LastArg = (BId == Builtin::BImemset ||
                       BId == Builtin::BIstrndup ? 1 : 2);
-  unsigned LenArg =
-      (BId == Builtin::BIbzero || BId == Builtin::BIstrndup ? 1 : 2);
+  unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2);
   const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts();
 
   if (CheckMemorySizeofForComparison(*this, LenExpr, FnName,