[polly] r246443 - Build the domains with correct number of dimensions

[Johannes Doerfert via llvm-commits]

Author: jdoerfert
Date: Mon Aug 31 08:56:32 2015
New Revision: 246443

URL: http://llvm.org/viewvc/llvm-project?rev=246443&view=rev
Log:
Build the domains with correct number of dimensions

  Instead of building domains with MaxLoopDepth dimensions, we now build
  the domains such that they have the right amount of dimensions all the
  time.


Modified:
    polly/trunk/lib/Analysis/ScopInfo.cpp

Modified: polly/trunk/lib/Analysis/ScopInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopInfo.cpp?rev=246443&r1=246442&r2=246443&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopInfo.cpp (original)
+++ polly/trunk/lib/Analysis/ScopInfo.cpp Mon Aug 31 08:56:32 2015
@@ -1488,19 +1488,16 @@ static inline Loop *getRegionNodeLoop(Re
 isl_set *Scop::getDomainConditions(ScopStmt *Stmt) {
   BasicBlock *BB = Stmt->isBlockStmt() ? Stmt->getBasicBlock()
                                        : Stmt->getRegion()->getEntry();
-  isl_set *Domain = isl_set_copy(DomainMap[BB]);
-
-  unsigned NumDims = Stmt->getNumIterators();
-  Domain = isl_set_remove_dims(Domain, isl_dim_set, NumDims,
-                               getMaxLoopDepth() - NumDims);
-  return Domain;
+  return isl_set_copy(DomainMap[BB]);
 }
 
 void Scop::buildDomains(Region *R, LoopInfo &LI, ScopDetection &SD,
                         DominatorTree &DT) {
 
-  auto *S = isl_set_universe(isl_space_set_alloc(getIslCtx(), 0, MaxLoopDepth));
-  DomainMap[R->getEntry()] = S;
+  auto *EntryBB = R->getEntry();
+  int LD = getRelativeLoopDepth(LI.getLoopFor(EntryBB));
+  auto *S = isl_set_universe(isl_space_set_alloc(getIslCtx(), 0, LD + 1));
+  DomainMap[EntryBB] = S;
 
   buildDomainsWithBranchConstraints(R, LI, SD, DT);
 }
@@ -1508,6 +1505,7 @@ void Scop::buildDomains(Region *R, LoopI
 void Scop::buildDomainsWithBranchConstraints(Region *R, LoopInfo &LI,
                                              ScopDetection &SD,
                                              DominatorTree &DT) {
+  RegionInfo &RI = *R->getRegionInfo();
 
   // To create the domain for each block in R we iterate over all blocks and
   // subregions in R and propagate the conditions under which the current region
@@ -1569,15 +1567,26 @@ void Scop::buildDomainsWithBranchConstra
         continue;
       }
 
-      // Check if the edge to SuccBB is a loop exit edge. If so drop the
-      // constrains on the loop/dimension we leave.
+      // Do not adjust the number of dimensions if we enter a boxed loop or are
+      // in a non-affine subregion or if the surrounding loop stays the same.
       Loop *SuccBBLoop = LI.getLoopFor(SuccBB);
-      if (SuccBBLoop != BBLoop &&
-          BBLoopDepth > getRelativeLoopDepth(SuccBBLoop)) {
-        assert(BBLoopDepth >= 0 &&
-               "Can only remove a dimension if we exit a loop");
-        CondSet = isl_set_drop_constraints_involving_dims(CondSet, isl_dim_set,
-                                                          BBLoopDepth, 1);
+      Region *SuccRegion = RI.getRegionFor(SuccBB);
+      if (BBLoop != SuccBBLoop && !RN->isSubRegion() &&
+          !(SD.isNonAffineSubRegion(SuccRegion, &getRegion()) &&
+            SuccRegion->contains(SuccBBLoop))) {
+
+        // Check if the edge to SuccBB is a loop entry or exit edge. If so
+        // adjust the dimensionality accordingly. Lastly, if we leave a loop
+        // and enter a new one we need to drop the old constraints.
+        int SuccBBLoopDepth = getRelativeLoopDepth(SuccBBLoop);
+        assert(std::abs(BBLoopDepth - SuccBBLoopDepth) <= 1);
+        if (BBLoopDepth > SuccBBLoopDepth)
+          CondSet = isl_set_remove_dims(CondSet, isl_dim_set, BBLoopDepth, 1);
+        else if (SuccBBLoopDepth > BBLoopDepth)
+          CondSet = isl_set_add_dims(CondSet, isl_dim_set, 1);
+        else if (BBLoopDepth >= 0)
+          CondSet = isl_set_drop_constraints_involving_dims(
+              CondSet, isl_dim_set, BBLoopDepth, 1);
       }
 
       // Set the domain for the successor or merge it with an existing domain in