[PATCH] D103096: [analyzer] Implement cast for ranges of symbolic integers.

[Valeriy Savchenko via Phabricator via cfe-commits]

vsavchenko added inline comments.


================
Comment at: clang/lib/StaticAnalyzer/Core/RangeConstraintManager.cpp:2506-2520
+  for (auto It = NTL.findByWidth(C.getIntWidth(T)) - 1; It >= NTL.begin();
+       --It) {
+    SymbolRef S = State->getSymbolManager().getCastSymbol(
+        RootSym, RootSym->getType(), *It);
+    if (const RangeSet *RS = getConstraint(State, S)) {
+      RangeSet TruncR = F.castTo(R, *It);
+      TruncR = F.intersect(*RS, TruncR);
----------------
What's the point of this when you do reverse operation in `Inferrer`?

As far as I understood, in `VisitSymbolCast`, you iterate over larger types and see if the same symbol was casted to any of those, and if yes you truncate the result and use that range.
Here, when we are about to set the constraint for a casted symbol, you iterate over smaller types, truncate this range for a smaller type, construct a cast to that smaller type, and add constraint for that symbol as well.

So, if this is correct, these two pieces of code DO THE SAME WORK and ONLY ONE should remain.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D103096/new/

https://reviews.llvm.org/D103096