[llvm] r324095 - [ThinLTO] - Add comment. NFC.

[George Rimar via llvm-commits]

Author: grimar
Date: Fri Feb  2 07:06:09 2018
New Revision: 324095

URL: http://llvm.org/viewvc/llvm-project?rev=324095&view=rev
Log:
[ThinLTO] - Add comment. NFC.

Was requested during review of D42798.

Modified:
    llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp

Modified: llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp?rev=324095&r1=324094&r2=324095&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp Fri Feb  2 07:06:09 2018
@@ -629,6 +629,8 @@ void llvm::convertToDeclaration(GlobalVa
     // need to add support here for creating either a function or
     // variable declaration, and return the new GlobalValue* for
     // the caller to use.
+    // Support of dropping aliases is required for correct dead code
+    // elimination performed in thin LTO backends (see 'dropDeadSymbols').
     llvm_unreachable("Expected function or variable");
 }