[FunctionAttrs] Add comment and clarify assertion message; NFC
llvm-svn: 252389
diff --git a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
index b63ffb4..907cede 100644
--- a/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -457,7 +457,12 @@
unsigned UseIndex = std::distance(CS.arg_begin(), U);
- assert(UseIndex < CS.data_operands_size() && "Non-argument use?");
+ // U cannot be the callee operand use: since we're exploring the
+ // transitive uses of an Argument, having such a use be a callee would
+ // imply the CallSite is an indirect call or invoke; and we'd take the
+ // early exit above.
+ assert(UseIndex < CS.data_operands_size() &&
+ "Data operand use expected!");
bool IsOperandBundleUse = UseIndex >= CS.getNumArgOperands();