[ValueLattice] Clarify that constant state can reached from undef.

As suggested as post-commit comment in D75845.
llvm · Mar 17, 2020 · 873ab73 · 873ab73
1 parent 73b1da1
commit 873ab73
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/llvm/include/llvm/Analysis/ValueLattice.h b/llvm/include/llvm/Analysis/ValueLattice.h
@@ -43,7 +43,8 @@ class ValueLatticeElement {
 
     /// This Value has a specific constant value.  The constant cannot be undef.
     /// (For constant integers, constantrange is used instead. Integer typed
-    /// constantexprs can appear as constant.)
+    /// constantexprs can appear as constant.) Note that the constant state
+    /// can be reached by merging undef & constant states.
     /// Transition allowed to the following states:
     ///  overdefined
     constant,