[clang] [KeyInstr][Clang] For range stmt atoms (PR #134647)

[Stephen Tozer via cfe-commits]

================
@@ -0,0 +1,87 @@
+// RUN: %clang_cc1 -triple x86_64-linux-gnu  -gkey-instructions %s -debug-info-kind=line-tables-only -emit-llvm -o - \
+// RUN: | FileCheck %s
+
+// Perennial question: should the inc be its own source atom or not
+// (currently it is).
+
+// FIXME: See do.c and while.c regarding cmp and cond br groups.
+
+// The stores in the setup (stores to __RANGE1, __BEGIN1, __END1) are all
+// marked as Key. Unclear whether that's desirable. Keep for now as that's
+// least risky (at worst it introduces an unecessary step while debugging,
----------------
SLTozer wrote:

```suggestion
// least risky (at worst it introduces an unnecessary step while debugging,
```

https://github.com/llvm/llvm-project/pull/134647