[Polly][docs][Release Notes] Adding Information about Remarks to Release Notes and Documentation

[tarunr]

Summary

Based off of D35399

[grosser]

Great! Thanks for working on this!

[tarunr]

Thanks! I will need somebody to commit this for me.

[tarunr]

Fixed an typo in displaying the url, and asterisk.

[Meinersbur]

This was already committed. You can open a new Phabricator review or commit such small and obvious changes directly.

If you like, I can commit the two additional characters myself directly.

[tarunr]

Thank you, I will someone else to commit this for me.

[tarunr]

This is typo is fixed in rL308505

docs/ReleaseNotes.rst

void isDiffEmptyOrUnionTheUniverse(__isl_take isl_set S1,
       if (IsUniverse == isl_bool_error)
         llvm_unreachable();
 
       if (IsUniverse)
         return true;
 
       return false;
     }
+
+--------------------------
+Improved Polly Diagnostics
+--------------------------
+
+Polly now uses the LLVM OptimizationDiagnosticInfo API for emitting diagnostic remarks.
+This allows Polly remarks to appear in the yaml optimization record when compiling
+with the flag -fsave-optimization-record. This also allow Polly remarks to appear in the opt-viewer
+tool, allowing for remarks to be viewed next to the source code, and sorted by hotness.

docs/UsingPollyWithClang.rst

 
 Import / Export
 ---------------
 
 The flags -polly-import and -polly-export allow the export and reimport of the
 polyhedral representation. By exporting, modifying and reimporting the
 polyhedral representation externally calculated transformations can be
 applied. This enables external optimizers or the manual optimization of
-specific SCoPs. 
+specific SCoPs.
+
+Viewing Polly Diagnostics with opt-viewer
+-----------------------------------------
+
+The flag -fsave-optimization-record will generate .opt.yaml files when compiling
+your program. These yaml files contain information about each emitted remark.
+Ensure that you have Python 2.7 with PyYaml and Pygments Python Packages.
+To run opt-viewer:
+
+.. code-block:: console
+
+   llvm/tools/opt-viewer/opt-viewer.py -source-dir /path/to/program/src/ \
+      /path/to/program/src/foo.opt.yaml \
+      /path/to/program/src/bar.opt.yaml \
+      -o ./output
+
+Include all yaml files (use \*.opt.yaml when specifying which yaml files to view)
+to view all diagnostics from your program in opt-viewer. Compile with `PGO
+<https://clang.llvm.org/docs/UsersManual.html#profiling-with-instrumentation>`_ to view
+Hotness information in opt-viewer. Resulting html files can be viewed in an internet browser.