Update comment, add assert for loads-into-fake-uses

Author: SLTozer

clang/lib/CodeGen/CGCall.cpp

@@ -3612,6 +3612,8 @@ static llvm::StoreInst *findDominatingStoreToReturnValue(CodeGenFunction &CGF) {
 
         if (II->getIntrinsicID() == llvm::Intrinsic::fake_use) {
           LoadIntoFakeUse = dyn_cast<llvm::Instruction>(II->getArgOperand(0));
+          assert(isa<llvm::LoadInst>(LoadIntoFakeUse) &&
+                 "Expected fake use operand to be a load instruction.");
           continue;
         }
       }

clang/lib/CodeGen/CGCleanup.h

@@ -87,7 +87,7 @@ class EHScope {
     LLVM_PREFERRED_TYPE(bool)
     unsigned IsLifetimeMarker : 1;
 
-    /// Whether this cleanup is a fake use
+    /// Whether this cleanup is a fake use.
     LLVM_PREFERRED_TYPE(bool)
     unsigned IsFakeUse : 1;