[PATCH] D13036: [LoopUnswitch] Require DominatorTree info.

[Michael Zolotukhin via llvm-commits]

mzolotukhin created this revision.
mzolotukhin added reviewers: chandlerc, hfinkel.
mzolotukhin added a subscriber: llvm-commits.

We should either require the DT info to be available, or check if it's
available in every place we use DT (and we already miss such check in
one place, which causes failures in some cases). As other loop passes
preserve DT and it's usually available, it makes sense to just require
it here.

http://reviews.llvm.org/D13036

Files:
  lib/Transforms/Scalar/LoopUnswitch.cpp

Index: lib/Transforms/Scalar/LoopUnswitch.cpp
===================================================================
--- lib/Transforms/Scalar/LoopUnswitch.cpp
+++ lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -193,6 +193,7 @@
       AU.addPreserved<LoopInfoWrapperPass>();
       AU.addRequiredID(LCSSAID);
       AU.addPreservedID(LCSSAID);
+      AU.addRequired<DominatorTreeWrapperPass>();
       AU.addPreserved<DominatorTreeWrapperPass>();
       AU.addPreserved<ScalarEvolutionWrapperPass>();
       AU.addRequired<TargetTransformInfoWrapperPass>();
@@ -412,23 +413,19 @@
       *L->getHeader()->getParent());
   LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
   LPM = &LPM_Ref;
-  DominatorTreeWrapperPass *DTWP =
-      getAnalysisIfAvailable<DominatorTreeWrapperPass>();
-  DT = DTWP ? &DTWP->getDomTree() : nullptr;
+  DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
   currentLoop = L;
   Function *F = currentLoop->getHeader()->getParent();
   bool Changed = false;
   do {
-    assert(!DT || currentLoop->isLCSSAForm(*DT));
+    assert(currentLoop->isLCSSAForm(*DT));
     redoLoop = false;
     Changed |= processCurrentLoop();
   } while(redoLoop);
 
-  if (Changed) {
-    // FIXME: Reconstruct dom info, because it is not preserved properly.
-    if (DT)
-      DT->recalculate(*F);
-  }
+  // FIXME: Reconstruct dom info, because it is not preserved properly.
+  if (Changed)
+    DT->recalculate(*F);
   return Changed;
 }
 
@@ -1196,8 +1193,7 @@
     // domtree here -- instead we force it to do a full recomputation
     // after the pass is complete -- but we do need to inform it of
     // new blocks.
-    if (DT)
-      DT->addNewBlock(Abort, NewSISucc);
+    DT->addNewBlock(Abort, NewSISucc);
   }
 
   SimplifyCode(Worklist, L);


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