MFC r309124:

Upgrade our copies of clang, llvm, lldb, compiler-rt and libc++ to 3.9.0
release, and add lld 3.9.0.  Also completely revamp the build system for
clang, llvm, lldb and their related tools.

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

Release notes for llvm, clang and lld are available here:
<http://llvm.org/releases/3.9.0/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/clang/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Bryan Drewery, Andrew Turner, Antoine Brodin and Jan
Beich for their help.

Relnotes:	yes

MFC r309147:

Pull in r282174 from upstream llvm trunk (by Krzysztof Parzyszek):

  [PPC] Set SP after loading data from stack frame, if no red zone is
  present

  Follow-up to r280705: Make sure that the SP is only restored after
  all data is loaded from the stack frame, if there is no red zone.

  This completes the fix for
  https://llvm.org/bugs/show_bug.cgi?id=26519.

  Differential Revision: https://reviews.llvm.org/D24466

Reported by:    Mark Millard
PR:             214433

MFC r309149:

Pull in r283060 from upstream llvm trunk (by Hal Finkel):

  [PowerPC] Refactor soft-float support, and enable PPC64 soft float

  This change enables soft-float for PowerPC64, and also makes
  soft-float disable all vector instruction sets for both 32-bit and
  64-bit modes. This latter part is necessary because the PPC backend
  canonicalizes many Altivec vector types to floating-point types, and
  so soft-float breaks scalarization support for many operations. Both
  for embedded targets and for operating-system kernels desiring
  soft-float support, it seems reasonable that disabling hardware
  floating-point also disables vector instructions (embedded targets
  without hardware floating point support are unlikely to have Altivec,
  etc. and operating system kernels desiring not to use floating-point
  registers to lower syscall cost are unlikely to want to use vector
  registers either). If someone needs this to work, we'll need to
  change the fact that we promote many Altivec operations to act on
  v4f32. To make it possible to disable Altivec when soft-float is
  enabled, hardware floating-point support needs to be expressed as a
  positive feature, like the others, and not a negative feature,
  because target features cannot have dependencies on the disabling of
  some other feature. So +soft-float has now become -hard-float.

  Fixes PR26970.

Pull in r283061 from upstream clang trunk (by Hal Finkel):

  [PowerPC] Enable soft-float for PPC64, and +soft-float -> -hard-float

  Enable soft-float support on PPC64, as the backend now supports it.
  Also, the backend now uses -hard-float instead of +soft-float, so set
  the target features accordingly.

  Fixes PR26970.

Reported by:	Mark Millard
PR:		214433

MFC r309212:

Add a few missed clang 3.9.0 files to OptionalObsoleteFiles.

MFC r309262:

Fix packaging for clang, lldb and lld 3.9.0

During the upgrade of clang/llvm etc to 3.9.0 in r309124, the PACKAGE
directive in the usr.bin/clang/*.mk files got dropped accidentally.

Restore it, with a few minor changes and additions:
* Correct license in clang.ucl to NCSA
* Add PACKAGE=clang for clang and most of the "ll" tools
* Put lldb in its own package
* Put lld in its own package

Reviewed by:	gjb, jmallett
Differential Revision: https://reviews.freebsd.org/D8666

MFC r309656:

During the bootstrap phase, when building the minimal llvm library on
PowerPC, add lib/Support/Atomic.cpp.  This is needed because upstream
llvm revision r271821 disabled the use of std::call_once, which causes
some fallback functions from Atomic.cpp to be used instead.

Reported by:	Mark Millard
PR:		214902

MFC r309835:

Tentatively apply https://reviews.llvm.org/D18730 to work around gcc PR
70528 (bogus error: constructor required before non-static data member).
This should fix buildworld with the external gcc package.

Reported by:	https://jenkins.freebsd.org/job/FreeBSD_HEAD_amd64_gcc/

MFC r310194:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
3.9.1 release.

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

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/3.9.1/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/lld/docs/ReleaseNotes.html>

Relnotes:	yes

1 files changed, 216 insertions, 0 deletions

diff --git a/contrib/llvm/lib/Analysis/LoopUnrollAnalyzer.cpp b/contrib/llvm/lib/Analysis/LoopUnrollAnalyzer.cpp
new file mode 100644
index 0000000..7bdf340
--- /dev/null
+++ b/contrib/llvm/lib/Analysis/LoopUnrollAnalyzer.cpp
@@ -0,0 +1,216 @@
+//===- LoopUnrollAnalyzer.cpp - Unrolling Effect Estimation -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements UnrolledInstAnalyzer class. It's used for predicting
+// potential effects that loop unrolling might have, such as enabling constant
+// propagation and other optimizations.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/LoopUnrollAnalyzer.h"
+#include "llvm/IR/Dominators.h"
+
+using namespace llvm;
+
+/// \brief Try to simplify instruction \param I using its SCEV expression.
+///
+/// The idea is that some AddRec expressions become constants, which then
+/// could trigger folding of other instructions. However, that only happens
+/// for expressions whose start value is also constant, which isn't always the
+/// case. In another common and important case the start value is just some
+/// address (i.e. SCEVUnknown) - in this case we compute the offset and save
+/// it along with the base address instead.
+bool UnrolledInstAnalyzer::simplifyInstWithSCEV(Instruction *I) {
+  if (!SE.isSCEVable(I->getType()))
+    return false;
+
+  const SCEV *S = SE.getSCEV(I);
+  if (auto *SC = dyn_cast<SCEVConstant>(S)) {
+    SimplifiedValues[I] = SC->getValue();
+    return true;
+  }
+
+  auto *AR = dyn_cast<SCEVAddRecExpr>(S);
+  if (!AR || AR->getLoop() != L)
+    return false;
+
+  const SCEV *ValueAtIteration = AR->evaluateAtIteration(IterationNumber, SE);
+  // Check if the AddRec expression becomes a constant.
+  if (auto *SC = dyn_cast<SCEVConstant>(ValueAtIteration)) {
+    SimplifiedValues[I] = SC->getValue();
+    return true;
+  }
+
+  // Check if the offset from the base address becomes a constant.
+  auto *Base = dyn_cast<SCEVUnknown>(SE.getPointerBase(S));
+  if (!Base)
+    return false;
+  auto *Offset =
+      dyn_cast<SCEVConstant>(SE.getMinusSCEV(ValueAtIteration, Base));
+  if (!Offset)
+    return false;
+  SimplifiedAddress Address;
+  Address.Base = Base->getValue();
+  Address.Offset = Offset->getValue();
+  SimplifiedAddresses[I] = Address;
+  return false;
+}
+
+/// Try to simplify binary operator I.
+///
+/// TODO: Probably it's worth to hoist the code for estimating the
+/// simplifications effects to a separate class, since we have a very similar
+/// code in InlineCost already.
+bool UnrolledInstAnalyzer::visitBinaryOperator(BinaryOperator &I) {
+  Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
+  if (!isa<Constant>(LHS))
+    if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS))
+      LHS = SimpleLHS;
+  if (!isa<Constant>(RHS))
+    if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
+      RHS = SimpleRHS;
+
+  Value *SimpleV = nullptr;
+  const DataLayout &DL = I.getModule()->getDataLayout();
+  if (auto FI = dyn_cast<FPMathOperator>(&I))
+    SimpleV =
+        SimplifyFPBinOp(I.getOpcode(), LHS, RHS, FI->getFastMathFlags(), DL);
+  else
+    SimpleV = SimplifyBinOp(I.getOpcode(), LHS, RHS, DL);
+
+  if (Constant *C = dyn_cast_or_null<Constant>(SimpleV))
+    SimplifiedValues[&I] = C;
+
+  if (SimpleV)
+    return true;
+  return Base::visitBinaryOperator(I);
+}
+
+/// Try to fold load I.
+bool UnrolledInstAnalyzer::visitLoad(LoadInst &I) {
+  Value *AddrOp = I.getPointerOperand();
+
+  auto AddressIt = SimplifiedAddresses.find(AddrOp);
+  if (AddressIt == SimplifiedAddresses.end())
+    return false;
+  ConstantInt *SimplifiedAddrOp = AddressIt->second.Offset;
+
+  auto *GV = dyn_cast<GlobalVariable>(AddressIt->second.Base);
+  // We're only interested in loads that can be completely folded to a
+  // constant.
+  if (!GV || !GV->hasDefinitiveInitializer() || !GV->isConstant())
+    return false;
+
+  ConstantDataSequential *CDS =
+      dyn_cast<ConstantDataSequential>(GV->getInitializer());
+  if (!CDS)
+    return false;
+
+  // We might have a vector load from an array. FIXME: for now we just bail
+  // out in this case, but we should be able to resolve and simplify such
+  // loads.
+  if (CDS->getElementType() != I.getType())
+    return false;
+
+  unsigned ElemSize = CDS->getElementType()->getPrimitiveSizeInBits() / 8U;
+  if (SimplifiedAddrOp->getValue().getActiveBits() > 64)
+    return false;
+  int64_t SimplifiedAddrOpV = SimplifiedAddrOp->getSExtValue();
+  if (SimplifiedAddrOpV < 0) {
+    // FIXME: For now we conservatively ignore out of bound accesses, but
+    // we're allowed to perform the optimization in this case.
+    return false;
+  }
+  uint64_t Index = static_cast<uint64_t>(SimplifiedAddrOpV) / ElemSize;
+  if (Index >= CDS->getNumElements()) {
+    // FIXME: For now we conservatively ignore out of bound accesses, but
+    // we're allowed to perform the optimization in this case.
+    return false;
+  }
+
+  Constant *CV = CDS->getElementAsConstant(Index);
+  assert(CV && "Constant expected.");
+  SimplifiedValues[&I] = CV;
+
+  return true;
+}
+
+/// Try to simplify cast instruction.
+bool UnrolledInstAnalyzer::visitCastInst(CastInst &I) {
+  // Propagate constants through casts.
+  Constant *COp = dyn_cast<Constant>(I.getOperand(0));
+  if (!COp)
+    COp = SimplifiedValues.lookup(I.getOperand(0));
+
+  // If we know a simplified value for this operand and cast is valid, save the
+  // result to SimplifiedValues.
+  // The cast can be invalid, because SimplifiedValues contains results of SCEV
+  // analysis, which operates on integers (and, e.g., might convert i8* null to
+  // i32 0).
+  if (COp && CastInst::castIsValid(I.getOpcode(), COp, I.getType())) {
+    if (Constant *C =
+            ConstantExpr::getCast(I.getOpcode(), COp, I.getType())) {
+      SimplifiedValues[&I] = C;
+      return true;
+    }
+  }
+
+  return Base::visitCastInst(I);
+}
+
+/// Try to simplify cmp instruction.
+bool UnrolledInstAnalyzer::visitCmpInst(CmpInst &I) {
+  Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
+
+  // First try to handle simplified comparisons.
+  if (!isa<Constant>(LHS))
+    if (Constant *SimpleLHS = SimplifiedValues.lookup(LHS))
+      LHS = SimpleLHS;
+  if (!isa<Constant>(RHS))
+    if (Constant *SimpleRHS = SimplifiedValues.lookup(RHS))
+      RHS = SimpleRHS;
+
+  if (!isa<Constant>(LHS) && !isa<Constant>(RHS)) {
+    auto SimplifiedLHS = SimplifiedAddresses.find(LHS);
+    if (SimplifiedLHS != SimplifiedAddresses.end()) {
+      auto SimplifiedRHS = SimplifiedAddresses.find(RHS);
+      if (SimplifiedRHS != SimplifiedAddresses.end()) {
+        SimplifiedAddress &LHSAddr = SimplifiedLHS->second;
+        SimplifiedAddress &RHSAddr = SimplifiedRHS->second;
+        if (LHSAddr.Base == RHSAddr.Base) {
+          LHS = LHSAddr.Offset;
+          RHS = RHSAddr.Offset;
+        }
+      }
+    }
+  }
+
+  if (Constant *CLHS = dyn_cast<Constant>(LHS)) {
+    if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
+      if (CLHS->getType() == CRHS->getType()) {
+        if (Constant *C = ConstantExpr::getCompare(I.getPredicate(), CLHS, CRHS)) {
+          SimplifiedValues[&I] = C;
+          return true;
+        }
+      }
+    }
+  }
+
+  return Base::visitCmpInst(I);
+}
+
+bool UnrolledInstAnalyzer::visitPHINode(PHINode &PN) {
+  // Run base visitor first. This way we can gather some useful for later
+  // analysis information.
+  if (Base::visitPHINode(PN))
+    return true;
+
+  // The loop induction PHI nodes are definitionally free.
+  return PN.getParent() == L->getHeader();
+}