[Polly] Avoid use of `getStmtFor(BB)` in PolyhedralInfo. NFC

[nandini12396]

Summary

Since there will be no more a 1-1 correspondence between statements and basic block, we would like to get rid of the method getStmtFor(BB) and its uses. Here we remove one of its uses in PolyhedralInfo, as suggested by Michael Sir.

[bollu]

include/polly/ScopInfo.h

2562 ↗

(On Diff #106180)

If we are eliminating getStmtFor, can this be removed?

lib/Analysis/PolyhedralInfo.cpp

135 ↗

(On Diff #106180)

Undesired change?

lib/Analysis/ScopInfo.cpp

4916 ↗

(On Diff #106180)

Please add an assert message along with the assert.

assert(StmtMapIt->second.size() == 1 && "We currently only have one Stmt per BB");

[nandini12396]

include/polly/ScopInfo.h

2562 ↗

(On Diff #106180)

yes, I am planning to remove it once I delete all its uses.

lib/Analysis/PolyhedralInfo.cpp

135 ↗

(On Diff #106180)

oh, this happened after polly-update-format. Thanks for pointing out.

lib/Analysis/ScopInfo.cpp

4916 ↗

(On Diff #106180)

oh, yes. Thanks I will add it.

[Meinersbur]

include/polly/ScopInfo.h

2565 ↗

(On Diff #106180)

Please do not return a copy of the entire vector. You can return:

1. A const std::vector<ScopStmt *>&
2. An ArrayRef<ScopStmt*>
3. An llvm::iterator_range<std::vector<ScopStmt *>::const_iterator>

lib/Analysis/PolyhedralInfo.cpp

129–130 ↗

(On Diff #106180)

These two loops only iterate once over all statements in a loop. It is simpler to do with

for (auto &SS : *S)
  if (L->contains(SS.getSurroundingLoop()))

which also protects from iterating region statements multiple times.

However, I am also fine with using getStmtListFor if we need it for other purposes as well.

[grosser]

I like Michael's idea! It does not even nee the getStmtList function.

[grosser]

Marking this as requesting changes to make sure I get notified when you update the commit.

[grosser]

This looks good to me

Let's wait for Michael's feedback!

polly/trunk/lib/Analysis/PolyhedralInfo.cpp

 //    Stmt[i0, i1] -> [i0, i1]
 __isl_give isl_union_map *PolyhedralInfo::getScheduleForLoop(const Scop *S,
                                                              Loop *L) const {
   isl_union_map *Schedule = isl_union_map_empty(S->getParamSpace());
   int CurrDim = S->getRelativeLoopDepth(L);
   DEBUG(dbgs() << "Relative loop depth:\t" << CurrDim << "\n");
   assert(CurrDim >= 0 && "Loop in region should have at least depth one");
 
-  for (auto *BB : L->blocks()) {
-    auto *SS = S->getStmtFor(BB);
-    if (!SS)
-      continue;
+  for (auto &SS : *S) {
+    if (L->contains(SS.getSurroundingLoop())) {
 
-    unsigned int MaxDim = SS->getNumIterators();
+      unsigned int MaxDim = SS.getNumIterators();
       DEBUG(dbgs() << "Maximum depth of Stmt:\t" << MaxDim << "\n");
-    auto *ScheduleMap = SS->getSchedule();
-    assert(ScheduleMap &&
-           "Schedules that contain extension nodes require special handling.");
+      auto *ScheduleMap = SS.getSchedule();
+      assert(
+          ScheduleMap &&
 
       ScheduleMap = isl_map_project_out(ScheduleMap, isl_dim_out, CurrDim + 1,
                                         MaxDim - CurrDim - 1);
       ScheduleMap =
-        isl_map_set_tuple_id(ScheduleMap, isl_dim_in, SS->getDomainId());
+          isl_map_set_tuple_id(ScheduleMap, isl_dim_in, SS.getDomainId());
       Schedule =
           isl_union_map_union(Schedule, isl_union_map_from_map(ScheduleMap));
     }
-
+  }
   Schedule = isl_union_map_coalesce(Schedule);
   return Schedule;
 }
 
 char PolyhedralInfo::ID = 0;
 
 Pass *polly::createPolyhedralInfoPass() { return new PolyhedralInfo(); }