Move getDebugLocation to ScopDetectionDiagnostic

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@210752 91177308-0d34-0410-b5e6-96231b3b80d8
Check for an empty error log.

Fixes #19976.

The error log does not contain an error, in case we reject a candidate
without generating a diagnostic message by using invalid<>(...). This is
the case for the top-level region of a function.

The patch comes without a test-case because adding a useful one requires
additional code just for triggering it. Before the patch it would only trigger,
if we try to print the CFG with Scop error annotations.

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@210753 91177308-0d34-0410-b5e6-96231b3b80d8
Fix typo

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@210754 91177308-0d34-0410-b5e6-96231b3b80d8
Do not use namespace polly inside a header.

In general this fixes ambiguity that can arise from using
a different namespace that declares the same symbols as
we do.

One example inside llvm would be:
  createIndVarSimplifyPass(..);

Which can be found in:
  llvm/Transforms/Scalar.h
and
  polly/LinkAllPasses.h

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@210755 91177308-0d34-0410-b5e6-96231b3b80d8