[ScopBuilder] Set domain to empty instead of NULL.

The domain generation used nullptr to mark the domain of an error block
as never-executed. Later, nullptr domains are recreated with a
zero-tuple domain that then mismatches with the expected domain the
error block within the loop.

Instead of using nullptr, assign an empty domain which preserves the
expected space. Remove empty domains during SCoP simplification.

Fixes llvm.org/PR38218.

llvm-svn: 338646

1 files changed, 1 insertions, 1 deletions

diff --git a/polly/include/polly/ScopInfo.h b/polly/include/polly/ScopInfo.h
index 1f56c94bebc..c6bf0e5e52e 100644
--- a/polly/include/polly/ScopInfo.h
+++ b/polly/include/polly/ScopInfo.h
@@ -2295,7 +2295,7 @@ private:
   void removeFromStmtMap(ScopStmt &Stmt);
 
   /// Removes all statements where the entry block of the statement does not
-  /// have a corresponding domain in the domain map.
+  /// have a corresponding domain in the domain map (or it is empty).
   void removeStmtNotInDomainMap();
 
   /// Mark arrays that have memory accesses with FortranArrayDescriptor.