[clang] [clang][dataflow] Check for backedges directly (instead of loop statements). (PR #68923)

[Yitzhak Mandelbaum via cfe-commits]

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@@ -53,19 +52,8 @@ static int blockIndexInPredecessor(const CFGBlock &Pred,
   return BlockPos - Pred.succ_begin();
 }
 
-static bool isLoopHead(const CFGBlock &B) {
-  if (const auto *T = B.getTerminatorStmt())
-    switch (T->getStmtClass()) {
-      case Stmt::WhileStmtClass:
-      case Stmt::DoStmtClass:
-      case Stmt::ForStmtClass:
-      case Stmt::CXXForRangeStmtClass:
-        return true;
-      default:
-        return false;
-    }
-
-  return false;
+static bool isBackedgeNode(const CFGBlock &B) {
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ymand wrote:

https://github.com/llvm/llvm-project/blob/eb14f47bf1ccfda500ba3c3092d70e269f6f0b56/clang/include/clang/Analysis/CFG.h#L805

Fwiw, I think this comment is better than the one in the CFG, so I don't know that linking is worth much, especially since it can be found pretty easily just by looking at `getLoopTarget`.

https://github.com/llvm/llvm-project/pull/68923