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

[Donát Nagy via cfe-commits]

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@@ -441,10 +441,33 @@ void CoreEngine::HandleCallEnter(const CallEnter &CE, ExplodedNode *Pred) {
 void CoreEngine::HandleBranch(const Stmt *Cond, const Stmt *Term,
                                 const CFGBlock * B, ExplodedNode *Pred) {
   assert(B->succ_size() == 2);
+
+  const LocationContext *LC = Pred->getLocationContext();
+  BlockCounter Counter = WList->getBlockCounter();
+  unsigned BlockCount =
+      Counter.getNumVisited(LC->getStackFrame(), B->getBlockID());
+  std::optional<unsigned> IterationsFinishedInLoop = std::nullopt;
+  if (isa<ForStmt, WhileStmt, CXXForRangeStmt>(Term)) {
+    // FIXME: This code approximates the number of finished iteration based on
+    // the block count, i.e. the number of evaluations of the terminator block
+    // on the current execution path (which includes the current evaluation, so
+    // is always at least 1). This is probably acceptable for the
+    // checker-specific false positive suppression that currently uses this
+    // value, but it would be better to calcuate an accurate count of
+    // iterations.
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NagyDonat wrote:

It *was* wrapped to 79 columns (the default of the vim 'gw' command), but "checker-specific" and "iterations" are both very long words and they wouldn't fit even within 80 columns.

However I abbreviated "at least" to ">=" and rewrapped the text to make it visually nicer.

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