disabled for several months (since svn r88806) and no one noticed.  My fix
for pr6543 yesterday reenabled it, but broke the ARM port's code for using
TBB/TBH.  Rather than adding a target hook to disable merging for Thumb2 only,
I'm just taking this out.  It is not common to have identical jump tables,
the code we used to merge them was O(N^2), and it only helps code size, not
performance.

llvm-svn: 98977

llvm-svn: 98694

them with a counter.

llvm-svn: 98462

llvm-svn: 98181

llvm-svn: 98137

llvm-svn: 98108

llvm-svn: 98104

llvm-svn: 97938

llvm-svn: 97765

into TargetOpcodes.h.  #include the new TargetOpcodes.h
into MachineInstr.  Add new inline accessors (like isPHI())
to MachineInstr, and start using them throughout the 
codebase.

llvm-svn: 95687

1. MachineJumpTableInfo is now created lazily for a function the first time
   it actually makes a jump table instead of for every function.
2. The encoding of jump table entries is now described by the
   MachineJumpTableInfo::JTEntryKind enum.  This enum is determined by the
   TLI::getJumpTableEncoding() hook, instead of by lots of code scattered
   throughout the compiler that "knows" that jump table entries are always
   32-bits in pic mode (for example).
3. The size and alignment of jump table entries is now calculated based on
   their kind, instead of at machinefunction creation time.

Future work includes using the EntryKind in more places in the compiler,
eliminating other logic that "knows" the layout of jump tables in various
situations.

llvm-svn: 94470

Change errs() to dbgs().

llvm-svn: 92097

llvm-svn: 91477

llvm-svn: 91475

$ svn merge -c -91161 https://llvm.org/svn/llvm-project/llvm/trunk
--- Reverse-merging r91161 into '.':
U    lib/CodeGen/BranchFolding.cpp
U    lib/CodeGen/MachineBasicBlock.cpp
$ svn merge -c -91113 https://llvm.org/svn/llvm-project/llvm/trunk
--- Reverse-merging r91113 into '.':
G    lib/CodeGen/MachineBasicBlock.cpp
$ svn merge -c -91101 https://llvm.org/svn/llvm-project/llvm/trunk
--- Reverse-merging r91101 into '.':
U    include/llvm/CodeGen/MachineBasicBlock.h
G    lib/CodeGen/MachineBasicBlock.cpp
$ svn merge -c -91092 https://llvm.org/svn/llvm-project/llvm/trunk
--- Reverse-merging r91092 into '.':
G    include/llvm/CodeGen/MachineBasicBlock.h
G    lib/CodeGen/MachineBasicBlock.cpp

llvm-svn: 91376

branches only to a landing pad. Without this check, the compiler would go into
an infinite loop because the branch to a landing pad is an "abnormal" edge which
wasn't being taken into account.

This is the meat of that fix:

  if (!PrevBB.canFallThrough() && !MBB->BranchesToLandingPad(MBB)) {

The other stuff is simplification of the "branches to a landing pad" code.

llvm-svn: 91161

MachineBasicBlock::canFallThrough(), which is target-independent and more
thorough.

llvm-svn: 90634

Patch by Howard Hinnant!

llvm-svn: 90365

running tail duplication when doing branch folding for if-conversion, and
we also want to be able to run tail duplication earlier to fix some
reg alloc problems.  Move the CanFallThrough function from BranchFolding
to MachineBasicBlock so that it can be shared by TailDuplication.

llvm-svn: 89904

Make tail duplication of indirect branches much more aggressive (for targets
that indicate that it is profitable), based on further experience with
this transformation.  I compiled 3 large applications with and without
this more aggressive tail duplication and measured minimal changes in code
size.  ("size" on Darwin seems to round the text size up to the nearest
page boundary, so I can only say that any code size increase was less than
one 4k page.) Radar 7421267.

llvm-svn: 89814

llvm-svn: 89275

the tail of a block may make that block a new candidate for duplication.

llvm-svn: 89264

llvm-svn: 89254

llvm-svn: 89225

contents of the block to be duplicated.  Use this for ARM Cortex A8/9 to
be more aggressive tail duplicating indirect branches, since it makes it
much more likely that they will be predicted in the branch target buffer.
Testcase coming soon.

llvm-svn: 89187

unnecessary.  It is broken because the "isIdenticalTo" check should be
negated.  If that is fixed, this code causes the CodeGen/X86/tail-opts.ll
test to fail, in the dont_merge_oddly function.  And, I confirmed that the
regression is real -- the generated code is worse.  As far as I can tell,
that tail-opts.ll test is checking for what this code is supposed to handle
and we're doing the right thing anyway.

llvm-svn: 89121

llvm-svn: 89114

folding optimizations.

llvm-svn: 89109

It was too difficult to keep the heuristics for merging and duplication
consistent.

llvm-svn: 89105

llvm-svn: 88940

llvm-svn: 88932

llvm-svn: 88929

llvm-svn: 88927

code-size win, and not when it's only likely to be code-size neutral,
such as when only a single instruction would be eliminated and a new
branch would be required.

This fixes rdar://7392894.

llvm-svn: 88692

llvm-svn: 86928

llvm-svn: 86926

can be made to fall through into the other.

llvm-svn: 86909

instead of typedefs for std::pair. This simplifies the type of
SameTails, which previously was std::vector<std::pair<std::vector<std::pair<unsigned, MachineBasicBlock *> >::iterator, MachineBasicBlock::iterator>

llvm-svn: 86885

llvm-svn: 86875

tail merging support to handle more cases.
 - Recognize several cases where tail merging is beneficial even when
   the tail size is smaller than the generic threshold.
 - Make use of MachineInstrDesc::isBarrier to help detect
   non-fallthrough blocks.
 - Check for and avoid disrupting fall-through edges in more cases.

llvm-svn: 86871