[Flang] Add perfect-nest and rectangular-loop semantic tests #160276
                
     Closed
            
            
          
  Add this suggestion to a batch that can be applied as a single commit.
  This suggestion is invalid because no changes were made to the code.
  Suggestions cannot be applied while the pull request is closed.
  Suggestions cannot be applied while viewing a subset of changes.
  Only one suggestion per line can be applied in a batch.
  Add this suggestion to a batch that can be applied as a single commit.
  Applying suggestions on deleted lines is not supported.
  You must change the existing code in this line in order to create a valid suggestion.
  Outdated suggestions cannot be applied.
  This suggestion has been applied or marked resolved.
  Suggestions cannot be applied from pending reviews.
  Suggestions cannot be applied on multi-line comments.
  Suggestions cannot be applied while the pull request is queued to merge.
  Suggestion cannot be applied right now. Please check back later.
  
    
  
    
Add semantic tests of currently unsupported OpenMP canonical loops:
The message "Trip count must be computable and invariant" is the same that OpenACC emits for non-rectangular loops in
AccAttributeVisitor::CheckAssociatedLoop. I considered reusing the code, but calls OpenACC-only methods and has different behavior.