diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index bfea8fc..e49f285 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -4336,6 +4336,8 @@
 }
 
 bool llvm::propagatesFullPoison(const Instruction *I) {
+  // TODO: This should include all instructions apart from phis, selects and
+  // call-like instructions.
   switch (I->getOpcode()) {
   case Instruction::Add:
   case Instruction::Sub: