[clang] [KeyInstr][Clang] For stmt atom (PR #134646)

[Jeremy Morse via cfe-commits]

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@@ -1418,6 +1427,12 @@ void CodeGenFunction::EmitForStmt(const ForStmt &S,
 
   if (CGM.shouldEmitConvergenceTokens())
     ConvergenceTokenStack.pop_back();
+
+  if (FinalBodyBB) {
+    // Key Instructions: We want the for closing brace to be step-able on to
+    // match existing behaviour.
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jmorse wrote:

IMO the comment should indicate the intention of what `FinalBodyBB` -- presumably the last block of the body where the scope ends. Does this mean that for brace-less for loops, we could theoretically step on the same last-line twice if there's a simple assignment and then a branch?

https://github.com/llvm/llvm-project/pull/134646