Merge clang, llvm, lld, lldb, compiler-rt and libc++ 5.0.0 release.

MFC r309126 (by emaste):

  Correct lld llvm-tblgen dependency file name

MFC r309169:

  Get rid of separate Subversion mergeinfo properties for llvm-dwarfdump
  and llvm-lto.  The mergeinfo confuses Subversion enormously, and these
  directories will just use the mergeinfo for llvm itself.

MFC r312765:

  Pull in r276136 from upstream llvm trunk (by Wei Mi):

    Use ValueOffsetPair to enhance value reuse during SCEV expansion.

    In D12090, the ExprValueMap was added to reuse existing value during
    SCEV expansion. However, const folding and sext/zext distribution can
    make the reuse still difficult.

    A simplified case is: suppose we know S1 expands to V1 in
    ExprValueMap, and
      S1 = S2 + C_a
      S3 = S2 + C_b
    where C_a and C_b are different SCEVConstants. Then we'd like to
    expand S3 as V1 - C_a + C_b instead of expanding S2 literally. It is
    helpful when S2 is a complex SCEV expr and S2 has no entry in
    ExprValueMap, which is usually caused by the fact that S3 is
    generated from S1 after const folding.

    In order to do that, we represent ExprValueMap as a mapping from SCEV
    to ValueOffsetPair. We will save both S1->{V1, 0} and S2->{V1, C_a}
    into the ExprValueMap when we create SCEV for V1. When S3 is
    expanded, it will first expand S2 to V1 - C_a because of S2->{V1,
    C_a} in the map, then expand S3 to V1 - C_a + C_b.

    Differential Revision: https://reviews.llvm.org/D21313

  This should fix assertion failures when building OpenCV >= 3.1.

  PR:		215649

MFC r312831:

  Revert r312765 for now, since it causes assertions when building
  lang/spidermonkey24.

  Reported by:	antoine
  PR:		215649

MFC r316511 (by jhb):

  Add an implementation of __ffssi2() derived from __ffsdi2().

  Newer versions of GCC include an __ffssi2() symbol in libgcc and the
  compiler can emit calls to it in generated code.  This is true for at
  least GCC 6.2 when compiling world for mips and mips64.

  Reviewed by:	jmallett, dim
  Sponsored by:	DARPA / AFRL
  Differential Revision:	https://reviews.freebsd.org/D10086

MFC r318601 (by adrian):

  [libcompiler-rt] add bswapdi2/bswapsi2

  This is required for mips gcc 6.3 userland to build/run.

  Reviewed by:	emaste, dim
  Approved by:	emaste
  Differential Revision:	https://reviews.freebsd.org/D10838

MFC r318884 (by emaste):

  lldb: map TRAP_CAP to a trace trap

  In the absense of a more specific handler for TRAP_CAP (generated by
  ENOTCAPABLE or ECAPMODE while in capability mode) treat it as a trace
  trap.

  Example usage (testing the bug in PR219173):

  % proccontrol -m trapcap lldb usr.bin/hexdump/obj/hexdump -- -Cv -s 1 /bin/ls
  ...
  (lldb) run
  Process 12980 launching
  Process 12980 launched: '.../usr.bin/hexdump/obj/hexdump' (x86_64)
  Process 12980 stopped
  * thread #1, stop reason = trace
      frame #0: 0x0000004b80c65f1a libc.so.7`__sys_lseek + 10
  ...

  In the future we should have LLDB control the trapcap procctl itself
  (as it does with ASLR), as well as report a specific stop reason.
  This change eliminates an assertion failure from LLDB for now.

MFC r319796:

  Remove a few unneeded files from libllvm, libclang and liblldb.

MFC r319885 (by emaste):

  lld: ELF: Fix ICF crash on absolute symbol relocations.

  If two sections contained relocations to absolute symbols with the same
  value we would crash when trying to access their sections. Add a check that
  both symbols point to sections before accessing their sections, and treat
  absolute symbols as equal if their values are equal.

  Obtained from:	LLD commit r292578

MFC r319918:

  Revert r319796 for now, it can cause undefined references when linking
  in some circumstances.

  Reported by:	Shawn Webb <shawn.webb@hardenedbsd.org>

MFC r319957 (by emaste):

  lld: Add armelf emulation mode

  Obtained from:	LLD r305375

MFC r321369:

  Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
  5.0.0 (trunk r308421).  Upstream has branched for the 5.0.0 release,
  which should be in about a month.  Please report bugs and regressions,
  so we can get them into the release.

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

MFC r321420:

  Add a few more object files to liblldb, which should solve errors when
  linking the lldb executable in some cases.  In particular, when the
  -ffunction-sections -fdata-sections options are turned off, or
  ineffective.

  Reported by:	Shawn Webb, Mark Millard

MFC r321433:

  Cleanup stale Options.inc files from the previous libllvm build for
  clang 4.0.0.  Otherwise, these can get included before the two newly
  generated ones (which are different) for clang 5.0.0.

  Reported by:	Mark Millard

MFC r321439 (by bdrewery):

  Move llvm Options.inc hack from r321433 for NO_CLEAN to lib/clang/libllvm.

  The files are only ever generated to .OBJDIR, not to WORLDTMP (as a
  sysroot) and are only ever included from a compilation.  So using
  a beforebuild target here removes the file before the compilation
  tries to include it.

MFC r321664:

  Pull in r308891 from upstream llvm trunk (by Benjamin Kramer):

    [CodeGenPrepare] Cut off FindAllMemoryUses if there are too many uses.

    This avoids excessive compile time. The case I'm looking at is
    Function.cpp from an old version of LLVM that still had the giant
    memcmp string matcher in it. Before r308322 this compiled in about 2
    minutes, after it, clang takes infinite* time to compile it. With
    this patch we're at 5 min, which is still bad but this is a
    pathological case.

    The cut off at 20 uses was chosen by looking at other cut-offs in LLVM
    for user scanning. It's probably too high, but does the job and is
    very unlikely to regress anything.

    Fixes PR33900.

    * I'm impatient and aborted after 15 minutes, on the bug report it was
      killed after 2h.

  Pull in r308986 from upstream llvm trunk (by Simon Pilgrim):

    [X86][CGP] Reduce memcmp() expansion to 2 load pairs (PR33914)

    D35067/rL308322 attempted to support up to 4 load pairs for memcmp
    inlining which resulted in regressions for some optimized libc memcmp
    implementations (PR33914).

    Until we can match these more optimal cases, this patch reduces the
    memcmp expansion to a maximum of 2 load pairs (which matches what we
    do for -Os).

    This patch should be considered for the 5.0.0 release branch as well

    Differential Revision: https://reviews.llvm.org/D35830

  These fix a hang (or extremely long compile time) when building older
  LLVM ports.

  Reported by:    antoine
  PR:             219139

MFC r321719:

  Pull in r309503 from upstream clang trunk (by Richard Smith):

    PR33902: Invalidate line number cache when adding more text to
    existing buffer.

    This led to crashes as the line number cache would report a bogus
    line number for a line of code, and we'd try to find a nonexistent
    column within the line when printing diagnostics.

  This fixes an assertion when building the graphics/champlain port.

  Reported by:	antoine, kwm
  PR:		219139

MFC r321723:

  Upgrade our copies of clang, llvm, lld and lldb to r309439 from the
  upstream release_50 branch.  This is just after upstream's 5.0.0-rc1.

MFC r322320:

  Upgrade our copies of clang, llvm and libc++ to r310316 from the
  upstream release_50 branch.

MFC r322326 (by emaste):

  lldb: Make i386-*-freebsd expression work on JIT path

  * Enable i386 ABI creation for freebsd
  * Added an extra argument in ABISysV_i386::PrepareTrivialCall for mmap
    syscall
  * Unlike linux, the last argument of mmap is actually 64-bit(off_t).
    This requires us to push an additional word for the higher order bits.
  * Prior to this change, ktrace dump will show mmap failures due to
    invalid argument coming from the 6th mmap argument.

  Submitted by:	Karnajit Wangkhem
  Differential Revision:	https://reviews.llvm.org/D34776

MFC r322360 (by emaste):

  lldb: Report inferior signals as signals, not exceptions, on FreeBSD

  This is the FreeBSD equivalent of LLVM r238549.

  This serves 2 purposes:

  * LLDB should handle inferior process signals SIGSEGV/SIGILL/SIGBUS/
    SIGFPE the way it is suppose to be handled. Prior to this fix these
    signals will neither create a coredump, nor exit from the debugger
    or work for signal handling scenario.
  * eInvalidCrashReason need not report "unknown crash reason" if we have
    a valid si_signo

  llvm.org/pr23699

  Patch by Karnajit Wangkhem

  Differential Revision:  https://reviews.llvm.org/D35223

  Submitted by:	Karnajit Wangkhem
  Obtained from:	LLVM r310591

MFC r322474 (by emaste):

  lld: Add `-z muldefs` option.

  Obtained from:	LLVM r310757

MFC r322740:

  Upgrade our copies of clang, llvm, lld and libc++ to r311219 from the
  upstream release_50 branch.

MFC r322855:

  Upgrade our copies of clang, llvm, lldb and compiler-rt to r311606 from
  the upstream release_50 branch.

  As of this version, lib/msun's trig test should also work correctly
  again (see bug 220989 for more information).

  PR:		220989

MFC r323112:

  Upgrade our copies of clang, llvm, lldb and compiler-rt to r312293 from
  the upstream release_50 branch.  This corresponds to 5.0.0 rc4.

  As of this version, the cad/stepcode port should now compile in a more
  reasonable time on i386 (see bug 221836 for more information).

  PR:		221836

MFC r323245:

  Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
  5.0.0 release (upstream r312559).

  Release notes for llvm, clang and lld will be available here soon:
  <http://releases.llvm.org/5.0.0/docs/ReleaseNotes.html>
  <http://releases.llvm.org/5.0.0/tools/clang/docs/ReleaseNotes.html>
  <http://releases.llvm.org/5.0.0/tools/lld/docs/ReleaseNotes.html>

  Relnotes:	yes

1 files changed, 495 insertions, 0 deletions

diff --git a/contrib/llvm/lib/Transforms/Utils/VNCoercion.cpp b/contrib/llvm/lib/Transforms/Utils/VNCoercion.cpp
new file mode 100644
index 0000000..c3feea6
--- /dev/null
+++ b/contrib/llvm/lib/Transforms/Utils/VNCoercion.cpp
@@ -0,0 +1,495 @@
+#include "llvm/Transforms/Utils/VNCoercion.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/ConstantFolding.h"
+#include "llvm/Analysis/MemoryDependenceAnalysis.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/Support/Debug.h"
+
+#define DEBUG_TYPE "vncoerce"
+namespace llvm {
+namespace VNCoercion {
+
+/// Return true if coerceAvailableValueToLoadType will succeed.
+bool canCoerceMustAliasedValueToLoad(Value *StoredVal, Type *LoadTy,
+                                     const DataLayout &DL) {
+  // If the loaded or stored value is an first class array or struct, don't try
+  // to transform them.  We need to be able to bitcast to integer.
+  if (LoadTy->isStructTy() || LoadTy->isArrayTy() ||
+      StoredVal->getType()->isStructTy() || StoredVal->getType()->isArrayTy())
+    return false;
+
+  // The store has to be at least as big as the load.
+  if (DL.getTypeSizeInBits(StoredVal->getType()) < DL.getTypeSizeInBits(LoadTy))
+    return false;
+
+  // Don't coerce non-integral pointers to integers or vice versa.
+  if (DL.isNonIntegralPointerType(StoredVal->getType()) !=
+      DL.isNonIntegralPointerType(LoadTy))
+    return false;
+
+  return true;
+}
+
+template <class T, class HelperClass>
+static T *coerceAvailableValueToLoadTypeHelper(T *StoredVal, Type *LoadedTy,
+                                               HelperClass &Helper,
+                                               const DataLayout &DL) {
+  assert(canCoerceMustAliasedValueToLoad(StoredVal, LoadedTy, DL) &&
+         "precondition violation - materialization can't fail");
+  if (auto *C = dyn_cast<Constant>(StoredVal))
+    if (auto *FoldedStoredVal = ConstantFoldConstant(C, DL))
+      StoredVal = FoldedStoredVal;
+
+  // If this is already the right type, just return it.
+  Type *StoredValTy = StoredVal->getType();
+
+  uint64_t StoredValSize = DL.getTypeSizeInBits(StoredValTy);
+  uint64_t LoadedValSize = DL.getTypeSizeInBits(LoadedTy);
+
+  // If the store and reload are the same size, we can always reuse it.
+  if (StoredValSize == LoadedValSize) {
+    // Pointer to Pointer -> use bitcast.
+    if (StoredValTy->isPtrOrPtrVectorTy() && LoadedTy->isPtrOrPtrVectorTy()) {
+      StoredVal = Helper.CreateBitCast(StoredVal, LoadedTy);
+    } else {
+      // Convert source pointers to integers, which can be bitcast.
+      if (StoredValTy->isPtrOrPtrVectorTy()) {
+        StoredValTy = DL.getIntPtrType(StoredValTy);
+        StoredVal = Helper.CreatePtrToInt(StoredVal, StoredValTy);
+      }
+
+      Type *TypeToCastTo = LoadedTy;
+      if (TypeToCastTo->isPtrOrPtrVectorTy())
+        TypeToCastTo = DL.getIntPtrType(TypeToCastTo);
+
+      if (StoredValTy != TypeToCastTo)
+        StoredVal = Helper.CreateBitCast(StoredVal, TypeToCastTo);
+
+      // Cast to pointer if the load needs a pointer type.
+      if (LoadedTy->isPtrOrPtrVectorTy())
+        StoredVal = Helper.CreateIntToPtr(StoredVal, LoadedTy);
+    }
+
+    if (auto *C = dyn_cast<ConstantExpr>(StoredVal))
+      if (auto *FoldedStoredVal = ConstantFoldConstant(C, DL))
+        StoredVal = FoldedStoredVal;
+
+    return StoredVal;
+  }
+  // If the loaded value is smaller than the available value, then we can
+  // extract out a piece from it.  If the available value is too small, then we
+  // can't do anything.
+  assert(StoredValSize >= LoadedValSize &&
+         "canCoerceMustAliasedValueToLoad fail");
+
+  // Convert source pointers to integers, which can be manipulated.
+  if (StoredValTy->isPtrOrPtrVectorTy()) {
+    StoredValTy = DL.getIntPtrType(StoredValTy);
+    StoredVal = Helper.CreatePtrToInt(StoredVal, StoredValTy);
+  }
+
+  // Convert vectors and fp to integer, which can be manipulated.
+  if (!StoredValTy->isIntegerTy()) {
+    StoredValTy = IntegerType::get(StoredValTy->getContext(), StoredValSize);
+    StoredVal = Helper.CreateBitCast(StoredVal, StoredValTy);
+  }
+
+  // If this is a big-endian system, we need to shift the value down to the low
+  // bits so that a truncate will work.
+  if (DL.isBigEndian()) {
+    uint64_t ShiftAmt = DL.getTypeStoreSizeInBits(StoredValTy) -
+                        DL.getTypeStoreSizeInBits(LoadedTy);
+    StoredVal = Helper.CreateLShr(
+        StoredVal, ConstantInt::get(StoredVal->getType(), ShiftAmt));
+  }
+
+  // Truncate the integer to the right size now.
+  Type *NewIntTy = IntegerType::get(StoredValTy->getContext(), LoadedValSize);
+  StoredVal = Helper.CreateTruncOrBitCast(StoredVal, NewIntTy);
+
+  if (LoadedTy != NewIntTy) {
+    // If the result is a pointer, inttoptr.
+    if (LoadedTy->isPtrOrPtrVectorTy())
+      StoredVal = Helper.CreateIntToPtr(StoredVal, LoadedTy);
+    else
+      // Otherwise, bitcast.
+      StoredVal = Helper.CreateBitCast(StoredVal, LoadedTy);
+  }
+
+  if (auto *C = dyn_cast<Constant>(StoredVal))
+    if (auto *FoldedStoredVal = ConstantFoldConstant(C, DL))
+      StoredVal = FoldedStoredVal;
+
+  return StoredVal;
+}
+
+/// If we saw a store of a value to memory, and
+/// then a load from a must-aliased pointer of a different type, try to coerce
+/// the stored value.  LoadedTy is the type of the load we want to replace.
+/// IRB is IRBuilder used to insert new instructions.
+///
+/// If we can't do it, return null.
+Value *coerceAvailableValueToLoadType(Value *StoredVal, Type *LoadedTy,
+                                      IRBuilder<> &IRB, const DataLayout &DL) {
+  return coerceAvailableValueToLoadTypeHelper(StoredVal, LoadedTy, IRB, DL);
+}
+
+/// This function is called when we have a memdep query of a load that ends up
+/// being a clobbering memory write (store, memset, memcpy, memmove).  This
+/// means that the write *may* provide bits used by the load but we can't be
+/// sure because the pointers don't must-alias.
+///
+/// Check this case to see if there is anything more we can do before we give
+/// up.  This returns -1 if we have to give up, or a byte number in the stored
+/// value of the piece that feeds the load.
+static int analyzeLoadFromClobberingWrite(Type *LoadTy, Value *LoadPtr,
+                                          Value *WritePtr,
+                                          uint64_t WriteSizeInBits,
+                                          const DataLayout &DL) {
+  // If the loaded or stored value is a first class array or struct, don't try
+  // to transform them.  We need to be able to bitcast to integer.
+  if (LoadTy->isStructTy() || LoadTy->isArrayTy())
+    return -1;
+
+  int64_t StoreOffset = 0, LoadOffset = 0;
+  Value *StoreBase =
+      GetPointerBaseWithConstantOffset(WritePtr, StoreOffset, DL);
+  Value *LoadBase = GetPointerBaseWithConstantOffset(LoadPtr, LoadOffset, DL);
+  if (StoreBase != LoadBase)
+    return -1;
+
+  // If the load and store are to the exact same address, they should have been
+  // a must alias.  AA must have gotten confused.
+  // FIXME: Study to see if/when this happens.  One case is forwarding a memset
+  // to a load from the base of the memset.
+
+  // If the load and store don't overlap at all, the store doesn't provide
+  // anything to the load.  In this case, they really don't alias at all, AA
+  // must have gotten confused.
+  uint64_t LoadSize = DL.getTypeSizeInBits(LoadTy);
+
+  if ((WriteSizeInBits & 7) | (LoadSize & 7))
+    return -1;
+  uint64_t StoreSize = WriteSizeInBits / 8; // Convert to bytes.
+  LoadSize /= 8;
+
+  bool isAAFailure = false;
+  if (StoreOffset < LoadOffset)
+    isAAFailure = StoreOffset + int64_t(StoreSize) <= LoadOffset;
+  else
+    isAAFailure = LoadOffset + int64_t(LoadSize) <= StoreOffset;
+
+  if (isAAFailure)
+    return -1;
+
+  // If the Load isn't completely contained within the stored bits, we don't
+  // have all the bits to feed it.  We could do something crazy in the future
+  // (issue a smaller load then merge the bits in) but this seems unlikely to be
+  // valuable.
+  if (StoreOffset > LoadOffset ||
+      StoreOffset + StoreSize < LoadOffset + LoadSize)
+    return -1;
+
+  // Okay, we can do this transformation.  Return the number of bytes into the
+  // store that the load is.
+  return LoadOffset - StoreOffset;
+}
+
+/// This function is called when we have a
+/// memdep query of a load that ends up being a clobbering store.
+int analyzeLoadFromClobberingStore(Type *LoadTy, Value *LoadPtr,
+                                   StoreInst *DepSI, const DataLayout &DL) {
+  // Cannot handle reading from store of first-class aggregate yet.
+  if (DepSI->getValueOperand()->getType()->isStructTy() ||
+      DepSI->getValueOperand()->getType()->isArrayTy())
+    return -1;
+
+  Value *StorePtr = DepSI->getPointerOperand();
+  uint64_t StoreSize =
+      DL.getTypeSizeInBits(DepSI->getValueOperand()->getType());
+  return analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, StorePtr, StoreSize,
+                                        DL);
+}
+
+/// This function is called when we have a
+/// memdep query of a load that ends up being clobbered by another load.  See if
+/// the other load can feed into the second load.
+int analyzeLoadFromClobberingLoad(Type *LoadTy, Value *LoadPtr, LoadInst *DepLI,
+                                  const DataLayout &DL) {
+  // Cannot handle reading from store of first-class aggregate yet.
+  if (DepLI->getType()->isStructTy() || DepLI->getType()->isArrayTy())
+    return -1;
+
+  Value *DepPtr = DepLI->getPointerOperand();
+  uint64_t DepSize = DL.getTypeSizeInBits(DepLI->getType());
+  int R = analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, DepPtr, DepSize, DL);
+  if (R != -1)
+    return R;
+
+  // If we have a load/load clobber an DepLI can be widened to cover this load,
+  // then we should widen it!
+  int64_t LoadOffs = 0;
+  const Value *LoadBase =
+      GetPointerBaseWithConstantOffset(LoadPtr, LoadOffs, DL);
+  unsigned LoadSize = DL.getTypeStoreSize(LoadTy);
+
+  unsigned Size = MemoryDependenceResults::getLoadLoadClobberFullWidthSize(
+      LoadBase, LoadOffs, LoadSize, DepLI);
+  if (Size == 0)
+    return -1;
+
+  // Check non-obvious conditions enforced by MDA which we rely on for being
+  // able to materialize this potentially available value
+  assert(DepLI->isSimple() && "Cannot widen volatile/atomic load!");
+  assert(DepLI->getType()->isIntegerTy() && "Can't widen non-integer load");
+
+  return analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, DepPtr, Size * 8, DL);
+}
+
+int analyzeLoadFromClobberingMemInst(Type *LoadTy, Value *LoadPtr,
+                                     MemIntrinsic *MI, const DataLayout &DL) {
+  // If the mem operation is a non-constant size, we can't handle it.
+  ConstantInt *SizeCst = dyn_cast<ConstantInt>(MI->getLength());
+  if (!SizeCst)
+    return -1;
+  uint64_t MemSizeInBits = SizeCst->getZExtValue() * 8;
+
+  // If this is memset, we just need to see if the offset is valid in the size
+  // of the memset..
+  if (MI->getIntrinsicID() == Intrinsic::memset)
+    return analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, MI->getDest(),
+                                          MemSizeInBits, DL);
+
+  // If we have a memcpy/memmove, the only case we can handle is if this is a
+  // copy from constant memory.  In that case, we can read directly from the
+  // constant memory.
+  MemTransferInst *MTI = cast<MemTransferInst>(MI);
+
+  Constant *Src = dyn_cast<Constant>(MTI->getSource());
+  if (!Src)
+    return -1;
+
+  GlobalVariable *GV = dyn_cast<GlobalVariable>(GetUnderlyingObject(Src, DL));
+  if (!GV || !GV->isConstant())
+    return -1;
+
+  // See if the access is within the bounds of the transfer.
+  int Offset = analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, MI->getDest(),
+                                              MemSizeInBits, DL);
+  if (Offset == -1)
+    return Offset;
+
+  unsigned AS = Src->getType()->getPointerAddressSpace();
+  // Otherwise, see if we can constant fold a load from the constant with the
+  // offset applied as appropriate.
+  Src =
+      ConstantExpr::getBitCast(Src, Type::getInt8PtrTy(Src->getContext(), AS));
+  Constant *OffsetCst =
+      ConstantInt::get(Type::getInt64Ty(Src->getContext()), (unsigned)Offset);
+  Src = ConstantExpr::getGetElementPtr(Type::getInt8Ty(Src->getContext()), Src,
+                                       OffsetCst);
+  Src = ConstantExpr::getBitCast(Src, PointerType::get(LoadTy, AS));
+  if (ConstantFoldLoadFromConstPtr(Src, LoadTy, DL))
+    return Offset;
+  return -1;
+}
+
+template <class T, class HelperClass>
+static T *getStoreValueForLoadHelper(T *SrcVal, unsigned Offset, Type *LoadTy,
+                                     HelperClass &Helper,
+                                     const DataLayout &DL) {
+  LLVMContext &Ctx = SrcVal->getType()->getContext();
+
+  // If two pointers are in the same address space, they have the same size,
+  // so we don't need to do any truncation, etc. This avoids introducing
+  // ptrtoint instructions for pointers that may be non-integral.
+  if (SrcVal->getType()->isPointerTy() && LoadTy->isPointerTy() &&
+      cast<PointerType>(SrcVal->getType())->getAddressSpace() ==
+          cast<PointerType>(LoadTy)->getAddressSpace()) {
+    return SrcVal;
+  }
+
+  uint64_t StoreSize = (DL.getTypeSizeInBits(SrcVal->getType()) + 7) / 8;
+  uint64_t LoadSize = (DL.getTypeSizeInBits(LoadTy) + 7) / 8;
+  // Compute which bits of the stored value are being used by the load.  Convert
+  // to an integer type to start with.
+  if (SrcVal->getType()->isPtrOrPtrVectorTy())
+    SrcVal = Helper.CreatePtrToInt(SrcVal, DL.getIntPtrType(SrcVal->getType()));
+  if (!SrcVal->getType()->isIntegerTy())
+    SrcVal = Helper.CreateBitCast(SrcVal, IntegerType::get(Ctx, StoreSize * 8));
+
+  // Shift the bits to the least significant depending on endianness.
+  unsigned ShiftAmt;
+  if (DL.isLittleEndian())
+    ShiftAmt = Offset * 8;
+  else
+    ShiftAmt = (StoreSize - LoadSize - Offset) * 8;
+  if (ShiftAmt)
+    SrcVal = Helper.CreateLShr(SrcVal,
+                               ConstantInt::get(SrcVal->getType(), ShiftAmt));
+
+  if (LoadSize != StoreSize)
+    SrcVal = Helper.CreateTruncOrBitCast(SrcVal,
+                                         IntegerType::get(Ctx, LoadSize * 8));
+  return SrcVal;
+}
+
+/// This function is called when we have a memdep query of a load that ends up
+/// being a clobbering store.  This means that the store provides bits used by
+/// the load but the pointers don't must-alias.  Check this case to see if
+/// there is anything more we can do before we give up.
+Value *getStoreValueForLoad(Value *SrcVal, unsigned Offset, Type *LoadTy,
+                            Instruction *InsertPt, const DataLayout &DL) {
+
+  IRBuilder<> Builder(InsertPt);
+  SrcVal = getStoreValueForLoadHelper(SrcVal, Offset, LoadTy, Builder, DL);
+  return coerceAvailableValueToLoadTypeHelper(SrcVal, LoadTy, Builder, DL);
+}
+
+Constant *getConstantStoreValueForLoad(Constant *SrcVal, unsigned Offset,
+                                       Type *LoadTy, const DataLayout &DL) {
+  ConstantFolder F;
+  SrcVal = getStoreValueForLoadHelper(SrcVal, Offset, LoadTy, F, DL);
+  return coerceAvailableValueToLoadTypeHelper(SrcVal, LoadTy, F, DL);
+}
+
+/// This function is called when we have a memdep query of a load that ends up
+/// being a clobbering load.  This means that the load *may* provide bits used
+/// by the load but we can't be sure because the pointers don't must-alias.
+/// Check this case to see if there is anything more we can do before we give
+/// up.
+Value *getLoadValueForLoad(LoadInst *SrcVal, unsigned Offset, Type *LoadTy,
+                           Instruction *InsertPt, const DataLayout &DL) {
+  // If Offset+LoadTy exceeds the size of SrcVal, then we must be wanting to
+  // widen SrcVal out to a larger load.
+  unsigned SrcValStoreSize = DL.getTypeStoreSize(SrcVal->getType());
+  unsigned LoadSize = DL.getTypeStoreSize(LoadTy);
+  if (Offset + LoadSize > SrcValStoreSize) {
+    assert(SrcVal->isSimple() && "Cannot widen volatile/atomic load!");
+    assert(SrcVal->getType()->isIntegerTy() && "Can't widen non-integer load");
+    // If we have a load/load clobber an DepLI can be widened to cover this
+    // load, then we should widen it to the next power of 2 size big enough!
+    unsigned NewLoadSize = Offset + LoadSize;
+    if (!isPowerOf2_32(NewLoadSize))
+      NewLoadSize = NextPowerOf2(NewLoadSize);
+
+    Value *PtrVal = SrcVal->getPointerOperand();
+    // Insert the new load after the old load.  This ensures that subsequent
+    // memdep queries will find the new load.  We can't easily remove the old
+    // load completely because it is already in the value numbering table.
+    IRBuilder<> Builder(SrcVal->getParent(), ++BasicBlock::iterator(SrcVal));
+    Type *DestPTy = IntegerType::get(LoadTy->getContext(), NewLoadSize * 8);
+    DestPTy =
+        PointerType::get(DestPTy, PtrVal->getType()->getPointerAddressSpace());
+    Builder.SetCurrentDebugLocation(SrcVal->getDebugLoc());
+    PtrVal = Builder.CreateBitCast(PtrVal, DestPTy);
+    LoadInst *NewLoad = Builder.CreateLoad(PtrVal);
+    NewLoad->takeName(SrcVal);
+    NewLoad->setAlignment(SrcVal->getAlignment());
+
+    DEBUG(dbgs() << "GVN WIDENED LOAD: " << *SrcVal << "\n");
+    DEBUG(dbgs() << "TO: " << *NewLoad << "\n");
+
+    // Replace uses of the original load with the wider load.  On a big endian
+    // system, we need to shift down to get the relevant bits.
+    Value *RV = NewLoad;
+    if (DL.isBigEndian())
+      RV = Builder.CreateLShr(RV, (NewLoadSize - SrcValStoreSize) * 8);
+    RV = Builder.CreateTrunc(RV, SrcVal->getType());
+    SrcVal->replaceAllUsesWith(RV);
+
+    SrcVal = NewLoad;
+  }
+
+  return getStoreValueForLoad(SrcVal, Offset, LoadTy, InsertPt, DL);
+}
+
+Constant *getConstantLoadValueForLoad(Constant *SrcVal, unsigned Offset,
+                                      Type *LoadTy, const DataLayout &DL) {
+  unsigned SrcValStoreSize = DL.getTypeStoreSize(SrcVal->getType());
+  unsigned LoadSize = DL.getTypeStoreSize(LoadTy);
+  if (Offset + LoadSize > SrcValStoreSize)
+    return nullptr;
+  return getConstantStoreValueForLoad(SrcVal, Offset, LoadTy, DL);
+}
+
+template <class T, class HelperClass>
+T *getMemInstValueForLoadHelper(MemIntrinsic *SrcInst, unsigned Offset,
+                                Type *LoadTy, HelperClass &Helper,
+                                const DataLayout &DL) {
+  LLVMContext &Ctx = LoadTy->getContext();
+  uint64_t LoadSize = DL.getTypeSizeInBits(LoadTy) / 8;
+
+  // We know that this method is only called when the mem transfer fully
+  // provides the bits for the load.
+  if (MemSetInst *MSI = dyn_cast<MemSetInst>(SrcInst)) {
+    // memset(P, 'x', 1234) -> splat('x'), even if x is a variable, and
+    // independently of what the offset is.
+    T *Val = cast<T>(MSI->getValue());
+    if (LoadSize != 1)
+      Val =
+          Helper.CreateZExtOrBitCast(Val, IntegerType::get(Ctx, LoadSize * 8));
+    T *OneElt = Val;
+
+    // Splat the value out to the right number of bits.
+    for (unsigned NumBytesSet = 1; NumBytesSet != LoadSize;) {
+      // If we can double the number of bytes set, do it.
+      if (NumBytesSet * 2 <= LoadSize) {
+        T *ShVal = Helper.CreateShl(
+            Val, ConstantInt::get(Val->getType(), NumBytesSet * 8));
+        Val = Helper.CreateOr(Val, ShVal);
+        NumBytesSet <<= 1;
+        continue;
+      }
+
+      // Otherwise insert one byte at a time.
+      T *ShVal = Helper.CreateShl(Val, ConstantInt::get(Val->getType(), 1 * 8));
+      Val = Helper.CreateOr(OneElt, ShVal);
+      ++NumBytesSet;
+    }
+
+    return coerceAvailableValueToLoadTypeHelper(Val, LoadTy, Helper, DL);
+  }
+
+  // Otherwise, this is a memcpy/memmove from a constant global.
+  MemTransferInst *MTI = cast<MemTransferInst>(SrcInst);
+  Constant *Src = cast<Constant>(MTI->getSource());
+  unsigned AS = Src->getType()->getPointerAddressSpace();
+
+  // Otherwise, see if we can constant fold a load from the constant with the
+  // offset applied as appropriate.
+  Src =
+      ConstantExpr::getBitCast(Src, Type::getInt8PtrTy(Src->getContext(), AS));
+  Constant *OffsetCst =
+      ConstantInt::get(Type::getInt64Ty(Src->getContext()), (unsigned)Offset);
+  Src = ConstantExpr::getGetElementPtr(Type::getInt8Ty(Src->getContext()), Src,
+                                       OffsetCst);
+  Src = ConstantExpr::getBitCast(Src, PointerType::get(LoadTy, AS));
+  return ConstantFoldLoadFromConstPtr(Src, LoadTy, DL);
+}
+
+/// This function is called when we have a
+/// memdep query of a load that ends up being a clobbering mem intrinsic.
+Value *getMemInstValueForLoad(MemIntrinsic *SrcInst, unsigned Offset,
+                              Type *LoadTy, Instruction *InsertPt,
+                              const DataLayout &DL) {
+  IRBuilder<> Builder(InsertPt);
+  return getMemInstValueForLoadHelper<Value, IRBuilder<>>(SrcInst, Offset,
+                                                          LoadTy, Builder, DL);
+}
+
+Constant *getConstantMemInstValueForLoad(MemIntrinsic *SrcInst, unsigned Offset,
+                                         Type *LoadTy, const DataLayout &DL) {
+  // The only case analyzeLoadFromClobberingMemInst cannot be converted to a
+  // constant is when it's a memset of a non-constant.
+  if (auto *MSI = dyn_cast<MemSetInst>(SrcInst))
+    if (!isa<Constant>(MSI->getValue()))
+      return nullptr;
+  ConstantFolder F;
+  return getMemInstValueForLoadHelper<Constant, ConstantFolder>(SrcInst, Offset,
+                                                                LoadTy, F, DL);
+}
+} // namespace VNCoercion
+} // namespace llvm