[ScopBuilder] Remove superfluous while loop in buildDomains. NFC.

The while loop iterating parent loop in ScopBuilder::buildDomains is
unnecessary because either L or LD are later unused, this is a simple
patch removing it.

Patch by bin.narwal <bin.narwal@gmail.com>

Differential Revision: https://reviews.llvm.org/D66698

llvm-svn: 370368

polly/lib/Analysis/ScopBuilder.cpp

@@ -831,10 +831,6 @@ bool ScopBuilder::buildDomains(
   auto *S =
       isl_set_universe(isl_space_set_alloc(scop->getIslCtx().get(), 0, LD + 1));
 
-  while (LD-- >= 0) {
-    L = L->getParentLoop();
-  }
-
   InvalidDomainMap[EntryBB] = isl::manage(isl_set_empty(isl_set_get_space(S)));
   isl::noexceptions::set Domain = isl::manage(S);
   scop->setDomain(EntryBB, Domain);