ASDenysPetrov added a comment. Returning to the discussion raised in D102696 <https://reviews.llvm.org/D102696>, I'd like to share my vision. I think we can use much easier approach to use valid constraints at any point of time. The main idea is lazy-reasoning of the ranges. This approach:
- **doesn't** need to use **canonicalization**; - **doesn't** need to **update all** the constraints on **each** `setConstraint` call (using brute-force or any other structure traversals); - **add** an additional bindings for **every** simple operand on **each** //assignment// or //initialization//. - **remove** an invalid bindings for **every** simple operand on **each** //assignment// or //initialization//. - **recursively** get the **range** when and only when needed (lazy-reasoning). Example: a = b + 1; c = a - 5; if (b != 42) return 0; if(c == 38) return 1; return 0; `a = b + 1;` 1. LHS `a` lookup. LHS not found. 2. Add binding `$a = $b + 1` 3. Traverse through RHS `b + 1`. 4. `b` lookup. `b` not found. 5. Built a new expression `a - 1` for `b`. 6. Add binding for `b`: `$b = $a - 1` 7. `1` is a constant. Skip. `c = a - 1;` 1. LHS `c` lookup. LHS not found. 2. Add binding `$c = $a - 1` 3. Traverse through RHS `a - 1`. 4. `a` lookup. `a` found. 5. If LHS not found and `a` found, then skip. 6. `1` is a constant. Skip. `if (b != 42) return;` 1. Get the range of `$b`. Direct range not found. Add `$b` to the list of visited symbols. 2. Substitute bindings. From `$b != 42` to `$a - 1 == 42`. 3. Traverse through `$a - 1`. 4. Get the range of `$a`. Direct range not found. Add `$a` to the list of visited symbols. 5. `1` is a constant. Skip. 6. Substitute bindings. From `$a - 1 == 42` to `$b + 1 - 1 == 42`. 7. Traverse through `$b + 1 - 1`. 8. `$b` is in the list of already visited symbols. No way to find a range. 9. Create a range from the type [MIN, MAX]. 10. Perform comparison and produce a constraint for `b` [42, 42]. `if(c == 38) return;` 1. Get the range of `$c`. Direct range not found. Add `$c` to the list of visited symbols. 2. Substitute bindings. From `$c == 38` to `$a - 1 == 38`. 3. Traverse through `$a - 1`. 4. Get the range of `$a`. Direct range not found. Add `$a` to the list of visited symbols. 5. `1` is a constant. Skip. 6. Substitute bindings. From `$a - 1 == 38` to `$b + 1 - 5 == 38`. 7. Traverse through `$b + 1 - 5`. 8. Get the range of `$b`. Direct range **found** [42, 42]. 9. `1` is a constant. Skip. 10. `5` is a constant. Skip. 11. Calculate a new range for `$c` [38, 38]. 12. Condition is //true//. `return 1` P.S. I've just started thinking of the way to solve this problem. For now it's just a sketch of where I'm going. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D103317/new/ https://reviews.llvm.org/D103317 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
