llvm-project

7fb36ba3 - [flang] Detect loops whose branching is confined to their body (#225757)

[flang] Detect loops whose branching is confined to their body (#225757) A DO loop is classified as either structured or unstructured, and a single raw branch anywhere in its body forces the loop -- and every construct enclosing it -- onto the unstructured path. That is stronger than necessary. A loop keeps its structured control flow as long as its branching neither leaves its body nor enters it from outside. Classify such a loop separately from a fully unstructured one. This only classifies: lowering is unchanged. PFT dumps mark the new classification with '~', which is what the tests key on.