1 files changed, 17 insertions, 29 deletions

diff --git a/contrib/llvm-project/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp b/contrib/llvm-project/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
index 37389a695b45..c065e0269c64 100644
--- a/contrib/llvm-project/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
+++ b/contrib/llvm-project/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
@@ -76,6 +76,13 @@ private:
 };
 } // end anonymous namespace
 
+/// Insert (K, V) pair into the ValueToValueMap, and verify the key did not
+/// previously exist in the map, and the value was inserted.
+static void InsertNewValueIntoMap(ValueToValueMapTy &VM, Value *K, Value *V) {
+  bool Inserted = VM.insert({K, V}).second;
+  assert(Inserted);
+  (void)Inserted;
+}
 /// RewriteUsesOfClonedInstructions - We just cloned the instructions from the
 /// old header into the preheader.  If there were uses of the values produced by
 /// these instruction that were outside of the loop, we have to insert PHI nodes
@@ -300,7 +307,8 @@ bool LoopRotate::rotateLoop(Loop *L, bool SimplifiedLatch) {
   // For PHI nodes, the value available in OldPreHeader is just the
   // incoming value from OldPreHeader.
   for (; PHINode *PN = dyn_cast<PHINode>(I); ++I)
-    ValueMap[PN] = PN->getIncomingValueForBlock(OrigPreheader);
+    InsertNewValueIntoMap(ValueMap, PN,
+                          PN->getIncomingValueForBlock(OrigPreheader));
 
   // For the rest of the instructions, either hoist to the OrigPreheader if
   // possible or create a clone in the OldPreHeader if not.
@@ -358,13 +366,13 @@ bool LoopRotate::rotateLoop(Loop *L, bool SimplifiedLatch) {
     if (V && LI->replacementPreservesLCSSAForm(C, V)) {
       // If so, then delete the temporary instruction and stick the folded value
       // in the map.
-      ValueMap[Inst] = V;
+      InsertNewValueIntoMap(ValueMap, Inst, V);
       if (!C->mayHaveSideEffects()) {
         C->deleteValue();
         C = nullptr;
       }
     } else {
-      ValueMap[Inst] = C;
+      InsertNewValueIntoMap(ValueMap, Inst, C);
     }
     if (C) {
       // Otherwise, stick the new instruction into the new block!
@@ -376,7 +384,8 @@ bool LoopRotate::rotateLoop(Loop *L, bool SimplifiedLatch) {
           AC->registerAssumption(II);
       // MemorySSA cares whether the cloned instruction was inserted or not, and
       // not whether it can be remapped to a simplified value.
-      ValueMapMSSA[Inst] = C;
+      if (MSSAU)
+        InsertNewValueIntoMap(ValueMapMSSA, Inst, C);
     }
   }
 
@@ -396,7 +405,7 @@ bool LoopRotate::rotateLoop(Loop *L, bool SimplifiedLatch) {
   // Update MemorySSA before the rewrite call below changes the 1:1
   // instruction:cloned_instruction_or_value mapping.
   if (MSSAU) {
-    ValueMapMSSA[OrigHeader] = OrigPreheader;
+    InsertNewValueIntoMap(ValueMapMSSA, OrigHeader, OrigPreheader);
     MSSAU->updateForClonedBlockIntoPred(OrigHeader, OrigPreheader,
                                         ValueMapMSSA);
   }
@@ -615,30 +624,9 @@ bool LoopRotate::simplifyLoopLatch(Loop *L) {
   LLVM_DEBUG(dbgs() << "Folding loop latch " << Latch->getName() << " into "
                     << LastExit->getName() << "\n");
 
-  // Hoist the instructions from Latch into LastExit.
-  Instruction *FirstLatchInst = &*(Latch->begin());
-  LastExit->getInstList().splice(BI->getIterator(), Latch->getInstList(),
-                                 Latch->begin(), Jmp->getIterator());
-
-  // Update MemorySSA
-  if (MSSAU)
-    MSSAU->moveAllAfterMergeBlocks(Latch, LastExit, FirstLatchInst);
-
-  unsigned FallThruPath = BI->getSuccessor(0) == Latch ? 0 : 1;
-  BasicBlock *Header = Jmp->getSuccessor(0);
-  assert(Header == L->getHeader() && "expected a backward branch");
-
-  // Remove Latch from the CFG so that LastExit becomes the new Latch.
-  BI->setSuccessor(FallThruPath, Header);
-  Latch->replaceSuccessorsPhiUsesWith(LastExit);
-  Jmp->eraseFromParent();
-
-  // Nuke the Latch block.
-  assert(Latch->empty() && "unable to evacuate Latch");
-  LI->removeBlock(Latch);
-  if (DT)
-    DT->eraseNode(Latch);
-  Latch->eraseFromParent();
+  DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Eager);
+  MergeBlockIntoPredecessor(Latch, &DTU, LI, MSSAU, nullptr,
+                            /*PredecessorWithTwoSuccessors=*/true);
 
   if (MSSAU && VerifyMemorySSA)
     MSSAU->getMemorySSA()->verifyMemorySSA();