[Polly] Do not check JSON alignment of scalar accesses

[Meinersbur]

Summary

When importing a schedule, do not verify the load/store alignment of scalar accesses. Scalar loads/store are always created newly in code generation with no alignment restrictions. Previously, scalar alignment was checked if the access instruction happened to be a LoadInst or StoreInst, but only its array (MK_Array) access is relevant.

This will be implicitly unit-tested when the access instruction of a value read can be nullptr.

[grosser]

LGTM.

[jdoerfert]

Small comment

• signature.asc219 BDownload

lib/Exchange/JSONExporter.cpp

for (MemoryAccess *MA : Stmt) {
         isl_map_free(currentAccessMap);
         isl_map_free(newAccessMap);
         return false;
       }
 
       isl_id *OutId = isl_map_get_tuple_id(currentAccessMap, isl_dim_out);
       newAccessMap = isl_map_set_tuple_id(newAccessMap, isl_dim_out, OutId);
 
+      if (MA->isArrayKind()) {
         // We keep the old alignment, thus we cannot allow accesses to memory
-      // locations that were not accessed before if the alignment of the access
+        // locations that were not accessed before if the alignment of the
+        // access
         // is not the default alignment.
         bool SpecialAlignment = true;
         if (LoadInst *LoadI = dyn_cast<LoadInst>(MA->getAccessInstruction())) {
           SpecialAlignment =
               DL.getABITypeAlignment(LoadI->getType()) != LoadI->getAlignment();
         } else if (StoreInst *StoreI =
                        dyn_cast<StoreInst>(MA->getAccessInstruction())) {
           SpecialAlignment =
               DL.getABITypeAlignment(StoreI->getValueOperand()->getType()) !=
               StoreI->getAlignment();
         }
 
         if (SpecialAlignment) {
           isl_set *newAccessSet = isl_map_range(isl_map_copy(newAccessMap));
           isl_set *currentAccessSet =
               isl_map_range(isl_map_copy(currentAccessMap));
           bool isSubset = isl_set_is_subset(newAccessSet, currentAccessSet);
           isl_set_free(newAccessSet);
           isl_set_free(currentAccessSet);
 
           if (!isSubset) {
             errs() << "JScop file changes the accessed memory\n";
             isl_map_free(currentAccessMap);
             isl_map_free(newAccessMap);
             return false;
           }
         }
+      }
 
       // We need to copy the isl_ids for the parameter dimensions to the new
       // map. Without doing this the current map would have different
       // ids then the new one, even though both are named identically.
       for (unsigned i = 0; i < isl_map_dim(currentAccessMap, isl_dim_param);
            i++) {
         isl_id *id = isl_map_get_dim_id(currentAccessMap, isl_dim_param, i);
         newAccessMap = isl_map_set_dim_id(newAccessMap, isl_dim_param, i, id);