Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release:

MFC r309142 (by emaste):

Add WITH_LLD_AS_LD build knob

If set it installs LLD as /usr/bin/ld.  LLD (as of version 3.9) is not
capable of linking the world and kernel, but can self-host and link many
substantial applications. GNU ld continues to be used for the world and
kernel build, regardless of how this knob is set.

It is on by default for arm64, and off for all other CPU architectures.

Sponsored by:	The FreeBSD Foundation

MFC r310840:

Reapply 310775, now it also builds correctly if lldb is disabled:

Move llvm-objdump from CLANG_EXTRAS to installed by default

We currently install three tools from binutils 2.17.50: as, ld, and
objdump. Work is underway to migrate to a permissively-licensed
tool-chain, with one goal being the retirement of binutils 2.17.50.

LLVM's llvm-objdump is intended to be compatible with GNU objdump
although it is currently missing some options and may have formatting
differences. Enable it by default for testing and further investigation.
It may later be changed to install as /usr/bin/objdump, it becomes a
fully viable replacement.

Reviewed by:	emaste
Differential Revision:	https://reviews.freebsd.org/D8879

MFC r312855 (by emaste):

Rename LLD_AS_LD to LLD_IS_LD, for consistency with CLANG_IS_CC

Reported by:	Dan McGregor <dan.mcgregor usask.ca>

MFC r313559 | glebius | 2017-02-10 18:34:48 +0100 (Fri, 10 Feb 2017) | 5 lines

Don't check struct rtentry on FreeBSD, it is an internal kernel structure.
On other systems it may be API structure for SIOCADDRT/SIOCDELRT.

Reviewed by:	emaste, dim

MFC r314152 (by jkim):

Remove an assembler flag, which is redundant since r309124.  The upstream
took care of it by introducing a macro NO_EXEC_STACK_DIRECTIVE.

http://llvm.org/viewvc/llvm-project?rev=273500&view=rev

Reviewed by:	dim

MFC r314564:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
4.0.0 (branches/release_40 296509).  The release will follow soon.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Also note that as of 4.0.0, lld should be able to link the base system
on amd64 and aarch64.  See the WITH_LLD_IS_LLD setting in src.conf(5).
Though please be aware that this is work in progress.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/4.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Jan Beich, Antoine Brodin and Eric Fiselier for
their help.

Relnotes:	yes
Exp-run:	antoine
PR:		215969, 216008

MFC r314708:

For now, revert r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

This commit is the cause of excessive compile times on skein_block.c
(and possibly other files) during kernel builds on amd64.

We never saw the problematic behavior described in this upstream commit,
so for now it is better to revert it.  An upstream bug has been filed
here: https://bugs.llvm.org/show_bug.cgi?id=32142

Reported by:	mjg

MFC r314795:

Reapply r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

Pull in r296992 from upstream llvm trunk (by Sanjoy Das):

  [SCEV] Decrease the recursion threshold for CompareValueComplexity

  Fixes PR32142.

  r287232 accidentally increased the recursion threshold for
  CompareValueComplexity from 2 to 32.  This change reverses that
  change by introducing a separate flag for CompareValueComplexity's
  threshold.

The latter revision fixes the excessive compile times for skein_block.c.

MFC r314907 | mmel | 2017-03-08 12:40:27 +0100 (Wed, 08 Mar 2017) | 7 lines

Unbreak ARMv6 world.

The new compiler_rt library imported with clang 4.0.0 have several fatal
issues (non-functional __udivsi3 for example) with ARM specific instrict
functions. As temporary workaround, until upstream solve these problems,
disable all thumb[1][2] related feature.

MFC r315016:

Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release.
We were already very close to the last release candidate, so this is a
pretty minor update.

Relnotes:	yes

MFC r316005:

Revert r314907, and pull in r298713 from upstream compiler-rt trunk (by
Weiming Zhao):

  builtins: Select correct code fragments when compiling for Thumb1/Thum2/ARM ISA.

  Summary:
  Value of __ARM_ARCH_ISA_THUMB isn't based on the actual compilation
  mode (-mthumb, -marm), it reflect's capability of given CPU.

  Due to this:
   - use  __tbumb__ and __thumb2__ insteand of __ARM_ARCH_ISA_THUMB
   - use '.thumb' directive consistently  in all affected files
   - decorate all thumb functions using
     DEFINE_COMPILERRT_THUMB_FUNCTION()

  ---------
  Note: This patch doesn't fix broken Thumb1 variant of __udivsi3 !

  Reviewers: weimingz, rengolin, compnerd

  Subscribers: aemerson, dim

  Differential Revision: https://reviews.llvm.org/D30938

Discussed with:	mmel

1 files changed, 111 insertions, 157 deletions

diff --git a/contrib/llvm/lib/CodeGen/BranchFolding.cpp b/contrib/llvm/lib/CodeGen/BranchFolding.cpp
index 5dacbf9..6fba161 100644
--- a/contrib/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/contrib/llvm/lib/CodeGen/BranchFolding.cpp
@@ -110,9 +110,12 @@ bool BranchFolderPass::runOnMachineFunction(MachineFunction &MF) {
 
 BranchFolder::BranchFolder(bool defaultEnableTailMerge, bool CommonHoist,
                            MBFIWrapper &FreqInfo,
-                           const MachineBranchProbabilityInfo &ProbInfo)
-    : EnableHoistCommonCode(CommonHoist), MBBFreqInfo(FreqInfo),
-      MBPI(ProbInfo) {
+                           const MachineBranchProbabilityInfo &ProbInfo,
+                           unsigned MinTailLength)
+    : EnableHoistCommonCode(CommonHoist), MinCommonTailLength(MinTailLength),
+      MBBFreqInfo(FreqInfo), MBPI(ProbInfo) {
+  if (MinCommonTailLength == 0)
+    MinCommonTailLength = TailMergeSize;
   switch (FlagEnableTailMerge) {
   case cl::BOU_UNSET: EnableTailMerge = defaultEnableTailMerge; break;
   case cl::BOU_TRUE: EnableTailMerge = true; break;
@@ -141,59 +144,6 @@ void BranchFolder::RemoveDeadBlock(MachineBasicBlock *MBB) {
     MLI->removeBlock(MBB);
 }
 
-/// OptimizeImpDefsBlock - If a basic block is just a bunch of implicit_def
-/// followed by terminators, and if the implicitly defined registers are not
-/// used by the terminators, remove those implicit_def's. e.g.
-/// BB1:
-///   r0 = implicit_def
-///   r1 = implicit_def
-///   br
-/// This block can be optimized away later if the implicit instructions are
-/// removed.
-bool BranchFolder::OptimizeImpDefsBlock(MachineBasicBlock *MBB) {
-  SmallSet<unsigned, 4> ImpDefRegs;
-  MachineBasicBlock::iterator I = MBB->begin();
-  while (I != MBB->end()) {
-    if (!I->isImplicitDef())
-      break;
-    unsigned Reg = I->getOperand(0).getReg();
-    if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
-      for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
-           SubRegs.isValid(); ++SubRegs)
-        ImpDefRegs.insert(*SubRegs);
-    } else {
-      ImpDefRegs.insert(Reg);
-    }
-    ++I;
-  }
-  if (ImpDefRegs.empty())
-    return false;
-
-  MachineBasicBlock::iterator FirstTerm = I;
-  while (I != MBB->end()) {
-    if (!TII->isUnpredicatedTerminator(*I))
-      return false;
-    // See if it uses any of the implicitly defined registers.
-    for (const MachineOperand &MO : I->operands()) {
-      if (!MO.isReg() || !MO.isUse())
-        continue;
-      unsigned Reg = MO.getReg();
-      if (ImpDefRegs.count(Reg))
-        return false;
-    }
-    ++I;
-  }
-
-  I = MBB->begin();
-  while (I != FirstTerm) {
-    MachineInstr *ImpDefMI = &*I;
-    ++I;
-    MBB->erase(ImpDefMI);
-  }
-
-  return true;
-}
-
 /// OptimizeFunction - Perhaps branch folding, tail merging and other
 /// CFG optimizations on the given function.  Block placement changes the layout
 /// and may create new tail merging opportunities.
@@ -224,7 +174,6 @@ bool BranchFolder::OptimizeFunction(MachineFunction &MF,
     SmallVector<MachineOperand, 4> Cond;
     if (!TII->analyzeBranch(MBB, TBB, FBB, Cond, true))
       MadeChange |= MBB.CorrectExtraCFGEdges(TBB, FBB, !Cond.empty());
-    MadeChange |= OptimizeImpDefsBlock(&MBB);
   }
 
   // Recalculate funclet membership.
@@ -399,37 +348,16 @@ static unsigned ComputeCommonTailLength(MachineBasicBlock *MBB1,
   return TailLen;
 }
 
-void BranchFolder::computeLiveIns(MachineBasicBlock &MBB) {
-  if (!UpdateLiveIns)
-    return;
-
-  LiveRegs.init(TRI);
-  LiveRegs.addLiveOutsNoPristines(MBB);
-  for (MachineInstr &MI : make_range(MBB.rbegin(), MBB.rend()))
-    LiveRegs.stepBackward(MI);
-
-  for (unsigned Reg : LiveRegs) {
-    // Skip the register if we are about to add one of its super registers.
-    bool ContainsSuperReg = false;
-    for (MCSuperRegIterator SReg(Reg, TRI); SReg.isValid(); ++SReg) {
-      if (LiveRegs.contains(*SReg)) {
-        ContainsSuperReg = true;
-        break;
-      }
-    }
-    if (ContainsSuperReg)
-      continue;
-    MBB.addLiveIn(Reg);
-  }
-}
-
 /// ReplaceTailWithBranchTo - Delete the instruction OldInst and everything
 /// after it, replacing it with an unconditional branch to NewDest.
 void BranchFolder::ReplaceTailWithBranchTo(MachineBasicBlock::iterator OldInst,
                                            MachineBasicBlock *NewDest) {
   TII->ReplaceTailWithBranchTo(OldInst, NewDest);
 
-  computeLiveIns(*NewDest);
+  if (UpdateLiveIns) {
+    NewDest->clearLiveIns();
+    computeLiveIns(LiveRegs, *TRI, *NewDest);
+  }
 
   ++NumTailMerge;
 }
@@ -467,7 +395,8 @@ MachineBasicBlock *BranchFolder::SplitMBBAt(MachineBasicBlock &CurMBB,
   // NewMBB inherits CurMBB's block frequency.
   MBBFreqInfo.setBlockFreq(NewMBB, MBBFreqInfo.getBlockFreq(&CurMBB));
 
-  computeLiveIns(*NewMBB);
+  if (UpdateLiveIns)
+    computeLiveIns(LiveRegs, *TRI, *NewMBB);
 
   // Add the new block to the funclet.
   const auto &FuncletI = FuncletMembership.find(&CurMBB);
@@ -511,14 +440,14 @@ static void FixTail(MachineBasicBlock *CurMBB, MachineBasicBlock *SuccBB,
   if (I != MF->end() && !TII->analyzeBranch(*CurMBB, TBB, FBB, Cond, true)) {
     MachineBasicBlock *NextBB = &*I;
     if (TBB == NextBB && !Cond.empty() && !FBB) {
-      if (!TII->ReverseBranchCondition(Cond)) {
-        TII->RemoveBranch(*CurMBB);
-        TII->InsertBranch(*CurMBB, SuccBB, nullptr, Cond, dl);
+      if (!TII->reverseBranchCondition(Cond)) {
+        TII->removeBranch(*CurMBB);
+        TII->insertBranch(*CurMBB, SuccBB, nullptr, Cond, dl);
         return;
       }
     }
   }
-  TII->InsertBranch(*CurMBB, SuccBB, nullptr,
+  TII->insertBranch(*CurMBB, SuccBB, nullptr,
                     SmallVector<MachineOperand, 0>(), dl);
 }
 
@@ -591,13 +520,26 @@ static unsigned CountTerminators(MachineBasicBlock *MBB,
 /// and decide if it would be profitable to merge those tails.  Return the
 /// length of the common tail and iterators to the first common instruction
 /// in each block.
+/// MBB1, MBB2      The blocks to check
+/// MinCommonTailLength  Minimum size of tail block to be merged.
+/// CommonTailLen   Out parameter to record the size of the shared tail between
+///                 MBB1 and MBB2
+/// I1, I2          Iterator references that will be changed to point to the first
+///                 instruction in the common tail shared by MBB1,MBB2
+/// SuccBB          A common successor of MBB1, MBB2 which are in a canonical form
+///                 relative to SuccBB
+/// PredBB          The layout predecessor of SuccBB, if any.
+/// FuncletMembership  map from block to funclet #.
+/// AfterPlacement  True if we are merging blocks after layout. Stricter
+///                 thresholds apply to prevent undoing tail-duplication.
 static bool
 ProfitableToMerge(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2,
-                  unsigned minCommonTailLength, unsigned &CommonTailLen,
+                  unsigned MinCommonTailLength, unsigned &CommonTailLen,
                   MachineBasicBlock::iterator &I1,
                   MachineBasicBlock::iterator &I2, MachineBasicBlock *SuccBB,
                   MachineBasicBlock *PredBB,
-                  DenseMap<const MachineBasicBlock *, int> &FuncletMembership) {
+                  DenseMap<const MachineBasicBlock *, int> &FuncletMembership,
+                  bool AfterPlacement) {
   // It is never profitable to tail-merge blocks from two different funclets.
   if (!FuncletMembership.empty()) {
     auto Funclet1 = FuncletMembership.find(MBB1);
@@ -617,7 +559,11 @@ ProfitableToMerge(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2,
 
   // It's almost always profitable to merge any number of non-terminator
   // instructions with the block that falls through into the common successor.
-  if (MBB1 == PredBB || MBB2 == PredBB) {
+  // This is true only for a single successor. For multiple successors, we are
+  // trading a conditional branch for an unconditional one.
+  // TODO: Re-visit successor size for non-layout tail merging.
+  if ((MBB1 == PredBB || MBB2 == PredBB) &&
+      (!AfterPlacement || MBB1->succ_size() == 1)) {
     MachineBasicBlock::iterator I;
     unsigned NumTerms = CountTerminators(MBB1 == PredBB ? MBB2 : MBB1, I);
     if (CommonTailLen > NumTerms)
@@ -635,15 +581,18 @@ ProfitableToMerge(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2,
 
   // If both blocks have an unconditional branch temporarily stripped out,
   // count that as an additional common instruction for the following
-  // heuristics.
+  // heuristics. This heuristic is only accurate for single-succ blocks, so to
+  // make sure that during layout merging and duplicating don't crash, we check
+  // for that when merging during layout.
   unsigned EffectiveTailLen = CommonTailLen;
   if (SuccBB && MBB1 != PredBB && MBB2 != PredBB &&
+      (MBB1->succ_size() == 1 || !AfterPlacement) &&
       !MBB1->back().isBarrier() &&
       !MBB2->back().isBarrier())
     ++EffectiveTailLen;
 
   // Check if the common tail is long enough to be worthwhile.
-  if (EffectiveTailLen >= minCommonTailLength)
+  if (EffectiveTailLen >= MinCommonTailLength)
     return true;
 
   // If we are optimizing for code size, 2 instructions in common is enough if
@@ -666,7 +615,7 @@ ProfitableToMerge(MachineBasicBlock *MBB1, MachineBasicBlock *MBB2,
 /// those blocks appear in MergePotentials (where they are not necessarily
 /// consecutive).
 unsigned BranchFolder::ComputeSameTails(unsigned CurHash,
-                                        unsigned minCommonTailLength,
+                                        unsigned MinCommonTailLength,
                                         MachineBasicBlock *SuccBB,
                                         MachineBasicBlock *PredBB) {
   unsigned maxCommonTailLength = 0U;
@@ -679,10 +628,11 @@ unsigned BranchFolder::ComputeSameTails(unsigned CurHash,
     for (MPIterator I = std::prev(CurMPIter); I->getHash() == CurHash; --I) {
       unsigned CommonTailLen;
       if (ProfitableToMerge(CurMPIter->getBlock(), I->getBlock(),
-                            minCommonTailLength,
+                            MinCommonTailLength,
                             CommonTailLen, TrialBBI1, TrialBBI2,
                             SuccBB, PredBB,
-                            FuncletMembership)) {
+                            FuncletMembership,
+                            AfterBlockPlacement)) {
         if (CommonTailLen > maxCommonTailLength) {
           SameTails.clear();
           maxCommonTailLength = CommonTailLen;
@@ -749,8 +699,6 @@ bool BranchFolder::CreateCommonTailOnlyBlock(MachineBasicBlock *&PredBB,
     SameTails[commonTailIndex].getTailStartPos();
   MachineBasicBlock *MBB = SameTails[commonTailIndex].getBlock();
 
-  // If the common tail includes any debug info we will take it pretty
-  // randomly from one of the inputs.  Might be better to remove it?
   DEBUG(dbgs() << "\nSplitting BB#" << MBB->getNumber() << ", size "
                << maxCommonTailLength);
 
@@ -832,14 +780,13 @@ mergeOperations(MachineBasicBlock::iterator MBBIStartPos,
 // branch to Succ added (but the predecessor/successor lists need no
 // adjustment). The lone predecessor of Succ that falls through into Succ,
 // if any, is given in PredBB.
+// MinCommonTailLength - Except for the special cases below, tail-merge if
+// there are at least this many instructions in common.
 bool BranchFolder::TryTailMergeBlocks(MachineBasicBlock *SuccBB,
-                                      MachineBasicBlock *PredBB) {
+                                      MachineBasicBlock *PredBB,
+                                      unsigned MinCommonTailLength) {
   bool MadeChange = false;
 
-  // Except for the special cases below, tail-merge if there are at least
-  // this many instructions in common.
-  unsigned minCommonTailLength = TailMergeSize;
-
   DEBUG(dbgs() << "\nTryTailMergeBlocks: ";
         for (unsigned i = 0, e = MergePotentials.size(); i != e; ++i)
           dbgs() << "BB#" << MergePotentials[i].getBlock()->getNumber()
@@ -852,8 +799,8 @@ bool BranchFolder::TryTailMergeBlocks(MachineBasicBlock *SuccBB,
                    << PredBB->getNumber() << "\n";
         }
         dbgs() << "Looking for common tails of at least "
-               << minCommonTailLength << " instruction"
-               << (minCommonTailLength == 1 ? "" : "s") << '\n';
+               << MinCommonTailLength << " instruction"
+               << (MinCommonTailLength == 1 ? "" : "s") << '\n';
        );
 
   // Sort by hash value so that blocks with identical end sequences sort
@@ -867,10 +814,10 @@ bool BranchFolder::TryTailMergeBlocks(MachineBasicBlock *SuccBB,
     // Build SameTails, identifying the set of blocks with this hash code
     // and with the maximum number of instructions in common.
     unsigned maxCommonTailLength = ComputeSameTails(CurHash,
-                                                    minCommonTailLength,
+                                                    MinCommonTailLength,
                                                     SuccBB, PredBB);
 
-    // If we didn't find any pair that has at least minCommonTailLength
+    // If we didn't find any pair that has at least MinCommonTailLength
     // instructions in common, remove all blocks with this hash code and retry.
     if (SameTails.empty()) {
       RemoveBlocksWithHash(CurHash, SuccBB, PredBB);
@@ -928,6 +875,11 @@ bool BranchFolder::TryTailMergeBlocks(MachineBasicBlock *SuccBB,
     // Recompute common tail MBB's edge weights and block frequency.
     setCommonTailEdgeWeights(*MBB);
 
+    // Remove the original debug location from the common tail.
+    for (auto &MI : *MBB)
+      if (!MI.isDebugValue())
+        MI.setDebugLoc(DebugLoc());
+
     // MBB is common tail.  Adjust all other BB's to jump to this one.
     // Traversal must be forwards so erases work.
     DEBUG(dbgs() << "\nUsing common tail in BB#" << MBB->getNumber()
@@ -976,7 +928,7 @@ bool BranchFolder::TailMergeBlocks(MachineFunction &MF) {
 
     // See if we can do any tail merging on those.
     if (MergePotentials.size() >= 2)
-      MadeChange |= TryTailMergeBlocks(nullptr, nullptr);
+      MadeChange |= TryTailMergeBlocks(nullptr, nullptr, MinCommonTailLength);
   }
 
   // Look at blocks (IBB) with multiple predecessors (PBB).
@@ -1056,7 +1008,7 @@ bool BranchFolder::TailMergeBlocks(MachineFunction &MF) {
         // branch.
         SmallVector<MachineOperand, 4> NewCond(Cond);
         if (!Cond.empty() && TBB == IBB) {
-          if (TII->ReverseBranchCondition(NewCond))
+          if (TII->reverseBranchCondition(NewCond))
             continue;
           // This is the QBB case described above
           if (!FBB) {
@@ -1092,10 +1044,10 @@ bool BranchFolder::TailMergeBlocks(MachineFunction &MF) {
         // Remove the unconditional branch at the end, if any.
         if (TBB && (Cond.empty() || FBB)) {
           DebugLoc dl;  // FIXME: this is nowhere
-          TII->RemoveBranch(*PBB);
+          TII->removeBranch(*PBB);
           if (!Cond.empty())
             // reinsert conditional branch only, for now
-            TII->InsertBranch(*PBB, (TBB == IBB) ? FBB : TBB, nullptr,
+            TII->insertBranch(*PBB, (TBB == IBB) ? FBB : TBB, nullptr,
                               NewCond, dl);
         }
 
@@ -1110,7 +1062,7 @@ bool BranchFolder::TailMergeBlocks(MachineFunction &MF) {
         TriedMerging.insert(MergePotentials[i].getBlock());
 
     if (MergePotentials.size() >= 2)
-      MadeChange |= TryTailMergeBlocks(IBB, PredBB);
+      MadeChange |= TryTailMergeBlocks(IBB, PredBB, MinCommonTailLength);
 
     // Reinsert an unconditional branch if needed. The 1 below can occur as a
     // result of removing blocks in TryTailMergeBlocks.
@@ -1311,10 +1263,10 @@ ReoptimizeBlock:
     // a fall-through.
     if (PriorTBB && PriorTBB == PriorFBB) {
       DebugLoc dl = getBranchDebugLoc(PrevBB);
-      TII->RemoveBranch(PrevBB);
+      TII->removeBranch(PrevBB);
       PriorCond.clear();
       if (PriorTBB != MBB)
-        TII->InsertBranch(PrevBB, PriorTBB, nullptr, PriorCond, dl);
+        TII->insertBranch(PrevBB, PriorTBB, nullptr, PriorCond, dl);
       MadeChange = true;
       ++NumBranchOpts;
       goto ReoptimizeBlock;
@@ -1359,7 +1311,7 @@ ReoptimizeBlock:
     // If the previous branch *only* branches to *this* block (conditional or
     // not) remove the branch.
     if (PriorTBB == MBB && !PriorFBB) {
-      TII->RemoveBranch(PrevBB);
+      TII->removeBranch(PrevBB);
       MadeChange = true;
       ++NumBranchOpts;
       goto ReoptimizeBlock;
@@ -1369,8 +1321,8 @@ ReoptimizeBlock:
     // the condition is false, remove the uncond second branch.
     if (PriorFBB == MBB) {
       DebugLoc dl = getBranchDebugLoc(PrevBB);
-      TII->RemoveBranch(PrevBB);
-      TII->InsertBranch(PrevBB, PriorTBB, nullptr, PriorCond, dl);
+      TII->removeBranch(PrevBB);
+      TII->insertBranch(PrevBB, PriorTBB, nullptr, PriorCond, dl);
       MadeChange = true;
       ++NumBranchOpts;
       goto ReoptimizeBlock;
@@ -1381,10 +1333,10 @@ ReoptimizeBlock:
     // fall-through.
     if (PriorTBB == MBB) {
       SmallVector<MachineOperand, 4> NewPriorCond(PriorCond);
-      if (!TII->ReverseBranchCondition(NewPriorCond)) {
+      if (!TII->reverseBranchCondition(NewPriorCond)) {
         DebugLoc dl = getBranchDebugLoc(PrevBB);
-        TII->RemoveBranch(PrevBB);
-        TII->InsertBranch(PrevBB, PriorFBB, nullptr, NewPriorCond, dl);
+        TII->removeBranch(PrevBB);
+        TII->insertBranch(PrevBB, PriorFBB, nullptr, NewPriorCond, dl);
         MadeChange = true;
         ++NumBranchOpts;
         goto ReoptimizeBlock;
@@ -1416,13 +1368,13 @@ ReoptimizeBlock:
       if (DoTransform) {
         // Reverse the branch so we will fall through on the previous true cond.
         SmallVector<MachineOperand, 4> NewPriorCond(PriorCond);
-        if (!TII->ReverseBranchCondition(NewPriorCond)) {
+        if (!TII->reverseBranchCondition(NewPriorCond)) {
           DEBUG(dbgs() << "\nMoving MBB: " << *MBB
                        << "To make fallthrough to: " << *PriorTBB << "\n");
 
           DebugLoc dl = getBranchDebugLoc(PrevBB);
-          TII->RemoveBranch(PrevBB);
-          TII->InsertBranch(PrevBB, MBB, nullptr, NewPriorCond, dl);
+          TII->removeBranch(PrevBB);
+          TII->insertBranch(PrevBB, MBB, nullptr, NewPriorCond, dl);
 
           // Move this block to the end of the function.
           MBB->moveAfter(&MF.back());
@@ -1450,10 +1402,10 @@ ReoptimizeBlock:
     //    Loop: xxx; jncc Loop; jmp Out
     if (CurTBB && CurFBB && CurFBB == MBB && CurTBB != MBB) {
       SmallVector<MachineOperand, 4> NewCond(CurCond);
-      if (!TII->ReverseBranchCondition(NewCond)) {
+      if (!TII->reverseBranchCondition(NewCond)) {
         DebugLoc dl = getBranchDebugLoc(*MBB);
-        TII->RemoveBranch(*MBB);
-        TII->InsertBranch(*MBB, CurFBB, CurTBB, NewCond, dl);
+        TII->removeBranch(*MBB);
+        TII->insertBranch(*MBB, CurFBB, CurTBB, NewCond, dl);
         MadeChange = true;
         ++NumBranchOpts;
         goto ReoptimizeBlock;
@@ -1469,7 +1421,7 @@ ReoptimizeBlock:
       // This block may contain just an unconditional branch.  Because there can
       // be 'non-branch terminators' in the block, try removing the branch and
       // then seeing if the block is empty.
-      TII->RemoveBranch(*MBB);
+      TII->removeBranch(*MBB);
       // If the only things remaining in the block are debug info, remove these
       // as well, so this will behave the same as an empty block in non-debug
       // mode.
@@ -1500,8 +1452,8 @@ ReoptimizeBlock:
               PriorFBB = MBB;
             }
             DebugLoc pdl = getBranchDebugLoc(PrevBB);
-            TII->RemoveBranch(PrevBB);
-            TII->InsertBranch(PrevBB, PriorTBB, PriorFBB, PriorCond, pdl);
+            TII->removeBranch(PrevBB);
+            TII->insertBranch(PrevBB, PriorTBB, PriorFBB, PriorCond, pdl);
           }
 
           // Iterate through all the predecessors, revectoring each in-turn.
@@ -1526,9 +1478,9 @@ ReoptimizeBlock:
                   *PMBB, NewCurTBB, NewCurFBB, NewCurCond, true);
               if (!NewCurUnAnalyzable && NewCurTBB && NewCurTBB == NewCurFBB) {
                 DebugLoc pdl = getBranchDebugLoc(*PMBB);
-                TII->RemoveBranch(*PMBB);
+                TII->removeBranch(*PMBB);
                 NewCurCond.clear();
-                TII->InsertBranch(*PMBB, NewCurTBB, nullptr, NewCurCond, pdl);
+                TII->insertBranch(*PMBB, NewCurTBB, nullptr, NewCurCond, pdl);
                 MadeChange = true;
                 ++NumBranchOpts;
                 PMBB->CorrectExtraCFGEdges(NewCurTBB, nullptr, false);
@@ -1548,7 +1500,7 @@ ReoptimizeBlock:
       }
 
       // Add the branch back if the block is more than just an uncond branch.
-      TII->InsertBranch(*MBB, CurTBB, nullptr, CurCond, dl);
+      TII->insertBranch(*MBB, CurTBB, nullptr, CurCond, dl);
     }
   }
 
@@ -1585,7 +1537,7 @@ ReoptimizeBlock:
           if (CurFallsThru) {
             MachineBasicBlock *NextBB = &*std::next(MBB->getIterator());
             CurCond.clear();
-            TII->InsertBranch(*MBB, NextBB, nullptr, CurCond, DebugLoc());
+            TII->insertBranch(*MBB, NextBB, nullptr, CurCond, DebugLoc());
           }
           MBB->moveAfter(PredBB);
           MadeChange = true;
@@ -1615,18 +1567,22 @@ ReoptimizeBlock:
 
       // Okay, there is no really great place to put this block.  If, however,
       // the block before this one would be a fall-through if this block were
-      // removed, move this block to the end of the function.
+      // removed, move this block to the end of the function. There is no real
+      // advantage in "falling through" to an EH block, so we don't want to
+      // perform this transformation for that case.
+      //
+      // Also, Windows EH introduced the possibility of an arbitrary number of
+      // successors to a given block.  The analyzeBranch call does not consider
+      // exception handling and so we can get in a state where a block
+      // containing a call is followed by multiple EH blocks that would be
+      // rotated infinitely at the end of the function if the transformation
+      // below were performed for EH "FallThrough" blocks.  Therefore, even if
+      // that appears not to be happening anymore, we should assume that it is
+      // possible and not remove the "!FallThrough()->isEHPad" condition below.
       MachineBasicBlock *PrevTBB = nullptr, *PrevFBB = nullptr;
       SmallVector<MachineOperand, 4> PrevCond;
-      // We're looking for cases where PrevBB could possibly fall through to
-      // FallThrough, but if FallThrough is an EH pad that wouldn't be useful
-      // so here we skip over any EH pads so we might have a chance to find
-      // a branch target from PrevBB.
-      while (FallThrough != MF.end() && FallThrough->isEHPad())
-        ++FallThrough;
-      // Now check to see if the current block is sitting between PrevBB and
-      // a block to which it could fall through.
       if (FallThrough != MF.end() &&
+          !FallThrough->isEHPad() &&
           !TII->analyzeBranch(PrevBB, PrevTBB, PrevFBB, PrevCond, true) &&
           PrevBB.isSuccessor(&*FallThrough)) {
         MBB->moveAfter(&MF.back());
@@ -1720,10 +1676,8 @@ MachineBasicBlock::iterator findHoistingInsertPosAndDeps(MachineBasicBlock *MBB,
 
   // The terminator is probably a conditional branch, try not to separate the
   // branch from condition setting instruction.
-  MachineBasicBlock::iterator PI = Loc;
-  --PI;
-  while (PI != MBB->begin() && PI->isDebugValue())
-    --PI;
+  MachineBasicBlock::iterator PI =
+    skipDebugInstructionsBackward(std::prev(Loc), MBB->begin());
 
   bool IsDef = false;
   for (const MachineOperand &MO : PI->operands()) {
@@ -1817,18 +1771,11 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
   MachineBasicBlock::iterator FIE = FBB->end();
   while (TIB != TIE && FIB != FIE) {
     // Skip dbg_value instructions. These do not count.
-    if (TIB->isDebugValue()) {
-      while (TIB != TIE && TIB->isDebugValue())
-        ++TIB;
-      if (TIB == TIE)
-        break;
-    }
-    if (FIB->isDebugValue()) {
-      while (FIB != FIE && FIB->isDebugValue())
-        ++FIB;
-      if (FIB == FIE)
-        break;
-    }
+    TIB = skipDebugInstructionsForward(TIB, TIE);
+    FIB = skipDebugInstructionsForward(FIB, FIE);
+    if (TIB == TIE || FIB == FIE)
+      break;
+
     if (!TIB->isIdenticalTo(*FIB, MachineInstr::CheckKillDead))
       break;
 
@@ -1929,14 +1876,21 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
   FBB->erase(FBB->begin(), FIB);
 
   // Update livein's.
+  bool AddedLiveIns = false;
   for (unsigned i = 0, e = LocalDefs.size(); i != e; ++i) {
     unsigned Def = LocalDefs[i];
     if (LocalDefsSet.count(Def)) {
       TBB->addLiveIn(Def);
       FBB->addLiveIn(Def);
+      AddedLiveIns = true;
     }
   }
 
+  if (AddedLiveIns) {
+    TBB->sortUniqueLiveIns();
+    FBB->sortUniqueLiveIns();
+  }
+
   ++NumHoist;
   return true;
 }