Revert r275883 and r275891. They seem to cause PR28608.

Revert "[LoopSimplify] Update LCSSA after separating nested loops."

This reverts commit r275891.

Revert "[LCSSA] Post-process PHI-nodes created by SSAUpdate when constructing LCSSA form."

This reverts commit r275883.

llvm-svn: 276064

1 files changed, 1 insertions, 10 deletions

diff --git a/llvm/lib/Transforms/Utils/LCSSA.cpp b/llvm/lib/Transforms/Utils/LCSSA.cpp
index bee6e24d25a..9658966779b 100644
--- a/llvm/lib/Transforms/Utils/LCSSA.cpp
+++ b/llvm/lib/Transforms/Utils/LCSSA.cpp
@@ -115,8 +115,7 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
     SmallVector<PHINode *, 16> AddedPHIs;
     SmallVector<PHINode *, 8> PostProcessPHIs;
 
-    SmallVector<PHINode *, 4> InsertedPHIs;
-    SSAUpdater SSAUpdate(&InsertedPHIs);
+    SSAUpdater SSAUpdate;
     SSAUpdate.Initialize(I->getType(), I->getName());
 
     // Insert the LCSSA phi's into all of the exit blocks dominated by the
@@ -185,14 +184,6 @@ bool llvm::formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
 
       // Otherwise, do full PHI insertion.
       SSAUpdate.RewriteUse(*UseToRewrite);
-
-      // SSAUpdater might have inserted phi-nodes inside other loops. We'll need
-      // to post-process them to keep LCSSA form.
-      for (PHINode *InsertedPN : InsertedPHIs) {
-        if (auto *OtherLoop = LI.getLoopFor(InsertedPN->getParent()))
-          if (!L->contains(OtherLoop))
-            PostProcessPHIs.push_back(InsertedPN);
-      }
     }
 
     // Post process PHI instructions that were inserted into another disjoint