[clang] [analyzer] Suppress out of bounds reports after weak loop assumptions (PR #109804)

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In-Reply-To: <llvm.org/llvm/llvm-project/pull/109804 at github.com>


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@@ -323,12 +342,13 @@ class ExprEngine {
 
   /// ProcessBranch - Called by CoreEngine.  Used to generate successor
   ///  nodes by processing the 'effects' of a branch condition.
-  void processBranch(const Stmt *Condition,
-                     NodeBuilderContext& BuilderCtx,
-                     ExplodedNode *Pred,
-                     ExplodedNodeSet &Dst,
-                     const CFGBlock *DstT,
-                     const CFGBlock *DstF);
+  /// If the branch condition is a loop condition, IterationsFinishedInLoop is
+  /// the number of already finished iterations (0, 1, 2...); otherwise it's
+  /// std::nullopt.
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isuckatcs wrote:

Isn't binding the iteration count to the loop terminator sufficient?

Let's say we pass the terminator to `processBranch()` instead of the iteration count.
If there is no trait set for the terminator, we set it on the true branch, when the loop is entered.
If the terminator is already set, we know that we finished one iteration already and increment it.
If the condition is false and the loop is not entered again the trait is removed.

I'm not sure how well this would work though, since I didn't test it.

https://github.com/llvm/llvm-project/pull/109804