1 files changed, 11 insertions, 8 deletions

diff --git a/contrib/llvm-project/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/contrib/llvm-project/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index a91bf7b7af13..b0c622b98d5e 100644
--- a/contrib/llvm-project/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/contrib/llvm-project/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -224,13 +224,12 @@ void llvm::simplifyLoopAfterUnroll(Loop *L, bool SimplifyIVs, LoopInfo *LI,
   const DataLayout &DL = L->getHeader()->getModule()->getDataLayout();
   SmallVector<WeakTrackingVH, 16> DeadInsts;
   for (BasicBlock *BB : L->getBlocks()) {
-    for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E;) {
-      Instruction *Inst = &*I++;
-      if (Value *V = SimplifyInstruction(Inst, {DL, nullptr, DT, AC}))
-        if (LI->replacementPreservesLCSSAForm(Inst, V))
-          Inst->replaceAllUsesWith(V);
-      if (isInstructionTriviallyDead(Inst))
-        DeadInsts.emplace_back(Inst);
+    for (Instruction &Inst : llvm::make_early_inc_range(*BB)) {
+      if (Value *V = SimplifyInstruction(&Inst, {DL, nullptr, DT, AC}))
+        if (LI->replacementPreservesLCSSAForm(&Inst, V))
+          Inst.replaceAllUsesWith(V);
+      if (isInstructionTriviallyDead(&Inst))
+        DeadInsts.emplace_back(&Inst);
     }
     // We can't do recursive deletion until we're done iterating, as we might
     // have a phi which (potentially indirectly) uses instructions later in
@@ -515,6 +514,10 @@ LoopUnrollResult llvm::UnrollLoop(Loop *L, UnrollLoopOptions ULO, LoopInfo *LI,
   SmallVector<MDNode *, 6> LoopLocalNoAliasDeclScopes;
   identifyNoAliasScopesToClone(L->getBlocks(), LoopLocalNoAliasDeclScopes);
 
+  // We place the unrolled iterations immediately after the original loop
+  // latch.  This is a reasonable default placement if we don't have block
+  // frequencies, and if we do, well the layout will be adjusted later.
+  auto BlockInsertPt = std::next(LatchBlock->getIterator());
   for (unsigned It = 1; It != ULO.Count; ++It) {
     SmallVector<BasicBlock *, 8> NewBlocks;
     SmallDenseMap<const Loop *, Loop *, 4> NewLoops;
@@ -523,7 +526,7 @@ LoopUnrollResult llvm::UnrollLoop(Loop *L, UnrollLoopOptions ULO, LoopInfo *LI,
     for (LoopBlocksDFS::RPOIterator BB = BlockBegin; BB != BlockEnd; ++BB) {
       ValueToValueMapTy VMap;
       BasicBlock *New = CloneBasicBlock(*BB, VMap, "." + Twine(It));
-      Header->getParent()->getBasicBlockList().push_back(New);
+      Header->getParent()->getBasicBlockList().insert(BlockInsertPt, New);
 
       assert((*BB != Header || LI->getLoopFor(*BB) == L) &&
              "Header should not be in a sub-loop");