The second fix of "determination of statements that contain matrix multiplication"

[gareevroman]

Summary

Fix potential issue related to subtraction from an unsigned 0 in circularShiftOutputDims and check that a parameter of ScheduleTreeOptimizer::isMatrMultPattern contains a correct partial schedule.

[Meinersbur]

Thanks for the patch.

You could credit Mehdi Amini for finding the issue in the commit message.

Instead of "The second fix of" in the title try to summarize what it does independently of other commits. Avoids searching for the other commit in the commit list.

If the summary already has the format "<do stuff> and <do stuff>", can you commit those independently? It makes bisecting for finding a corrupting change more precise. In this case it would be
"Fix potential issue related to subtraction from an unsigned 0 in circularShiftOutputDims."
and
"Check that a parameter of ScheduleTreeOptimizer::isMatrMultPattern contains a correct partial schedule. NFC."

You can commit such obvious bugfixes right away.

[grosser]

Thanks for your quick reviews. They are perfect.

[gareevroman]

Thank you for the comment!

In D20969#448438, @Meinersbur wrote:

Thanks for the patch.

You could credit Mehdi Amini for finding the issue in the commit message.

Yes, I’ve planned to do it.

Instead of "The second fix of" in the title try to summarize what it does independently of other commits. Avoids searching for the other commit in the commit list.

If the summary already has the format "<do stuff> and <do stuff>", can you commit those independently? It makes bisecting for finding a corrupting change more precise. In this case it would be
"Fix potential issue related to subtraction from an unsigned 0 in circularShiftOutputDims."
and
"Check that a parameter of ScheduleTreeOptimizer::isMatrMultPattern contains a correct partial schedule. NFC."

You can commit such obvious bugfixes right away.

OK. I thought that it's already simple.

polly/trunk/lib/Transform/ScheduleOptimizer.cpp

static bool containsMatrMult(__isl_keep isl_map *PartialSchedule) {
   auto DimNum = isl_map_dim(PartialSchedule, isl_dim_in);
   return !isInputDimUsed((*MemA)->getAccessRelation(), DimNum - 1);
 }
 
 /// @brief Circular shift of output dimensions of the integer map.
 ///
 /// @param IslMap The isl map to be modified.
 static __isl_give isl_map *circularShiftOutputDims(__isl_take isl_map *IslMap) {
-  auto InputDimsId = isl_map_get_tuple_id(IslMap, isl_dim_in);
   auto DimNum = isl_map_dim(IslMap, isl_dim_out);
+  if (DimNum == 0)
+    return IslMap;
+  auto InputDimsId = isl_map_get_tuple_id(IslMap, isl_dim_in);
   IslMap = isl_map_move_dims(IslMap, isl_dim_in, 0, isl_dim_out, DimNum - 1, 1);
   IslMap = isl_map_move_dims(IslMap, isl_dim_out, 0, isl_dim_in, 0, 1);
   return isl_map_set_tuple_id(IslMap, isl_dim_in, InputDimsId);
 }
 
 bool ScheduleTreeOptimizer::isMatrMultPattern(
     __isl_keep isl_schedule_node *Node) {
   auto *PartialSchedule =