The main advantages here are way better heuristics, taking into account not
just loop depth but also __builtin_expect and other static heuristics and will
eventually learn how to use profile info. Most of the work in this patch is
pushing the MachineBlockFrequencyInfo analysis into the right places.

This is good for a 5% speedup on zlib's deflate (x86_64), there were some very
unfortunate spilling decisions in its hottest loop in longest_match(). Other
benchmarks I tried were mostly neutral.

This changes register allocation in subtle ways, update the tests for it.
2012-02-20-MachineCPBug.ll was deleted as it's very fragile and the instruction
it looked for was gone already (but the FileCheck pattern picked up unrelated
stuff).

llvm-svn: 184105

llvm-svn: 182527

To find the last use of a register unit, start from the bottom and scan
upwards until a user is found.

<rdar://problem/13353090>

llvm-svn: 176706

MachineInstrs don't have a slot index.

llvm-svn: 175961

automatically.

llvm-svn: 175673

related failures when running 'make check' without LiveVariables with the
verifier enabled. Some of the remaining failures elsewhere may still be fallout
from incorrect updating of LiveIntervals or the few missing cases left in the
two-address pass.

llvm-svn: 175672

common transformations. This includes updating repairIntervalsInRange() to
handle more cases.

llvm-svn: 175604

and removing instructions. The implementation seems more complicated than it
needs to be, but I couldn't find something simpler that dealt with all of the
corner cases.

Also add a call to repairIndexesInRange() from repairIntervalsInRange().

llvm-svn: 175601

arguably better than forward iterators for this use case, they are confusing and
there are some implementation problems with reverse iterators and MI bundles.

llvm-svn: 175393

llvm-svn: 175385

terminators that actually have register uses when splitting critical edges.

This commit also introduces a method repairIntervalsInRange() on LiveIntervals,
which allows for repairing LiveIntervals in a small range after an arbitrary
target hook modifies, inserts, and removes instructions. It's pretty limited
right now, but I hope to extend it to support all of the things that are done
by the convertToThreeAddress() target hooks.

llvm-svn: 175382

This is part of the plan to delete LiveVariables.

llvm-svn: 174783

This uses a liveness algorithm that does not depend on data from the
LiveVariables analysis, it is the first step towards removing
LiveVariables completely.

llvm-svn: 174774

into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.

There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.

The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.

I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).

I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.

llvm-svn: 171366

Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

llvm-svn: 169131

Assertion failed: (itr != mi2iMap.end() && "Instruction not found in maps.")
rdar://12777252.

llvm-svn: 169070

No functional change, just moved header files.

Targets can inject custom passes between register allocation and
rewriting. This makes it possible to tweak the register allocation
before rewriting, using the full global interference checking available
from LiveRegMatrix.

llvm-svn: 168806

The RegMaskSlots contains 'r' slots while NewIdx and OldIdx are 'B'
slots. This broke the checks in the assertions.

This fixes PR14302.

llvm-svn: 167625

This is a medium term workaround until we have a more robust solution
in the form of a register liveness utility for postRA passes.

llvm-svn: 166001

All callers can simply use the corresponding MRI functions.

llvm-svn: 165985

It is possible that the live range of the value being pruned loops back
into the kill MBB where the search started. When that happens, make sure
that the beginning of KillMBB is also pruned.

Instead of starting a DFS at KillMBB and skipping the root of the
search, start a DFS at each KillMBB successor, and allow the search to
loop back to KillMBB.

This fixes PR14078.

llvm-svn: 165872

Completely update one interval at a time instead of collecting live
range fragments to be updated. This avoids building data structures,
except for a single SmallPtrSet of updated intervals.

Also share code between handleMove() and handleMoveIntoBundle().

Add support for moving dead defs across other live values in the
interval. The MI scheduler can do that.

llvm-svn: 165824

Reserved register live ranges look like a set of dead defs - any uses of
reserved registers are ignored.

Instead of skipping the updating of reserved register operands entirely,
just ignore the use operands and treat the def operands normally.

No test case, handleMove() is not commonly used yet.

llvm-svn: 165060

The old-fashioned many-to-one value mapping doesn't always work when
merging vector lanes. A value can map to multiple different values, and
it can even be necessary to insert new PHIs.

When a value number is defined by a copy from a value number that
required SSa update, include the live range of the copied value number
in the SSA update as well. It is not necessarily a copy of the original
value number any longer.

llvm-svn: 164329

Add LIS::pruneValue() and extendToIndices(). These two functions are
used by the register coalescer when merging two live ranges requires
more than a trivial value mapping as supported by LiveInterval::join().

The pruneValue() function can remove the part of a value number that is
going to conflict in join(). Afterwards, extendToIndices can restore the
live range, using any new dominating value numbers and updating the SSA
form.

Use this complex value mapping to support merging a register into a
vector lane that has a conflicting value, but the clobbered lane is
undef.

llvm-svn: 164074

findLastUseBefore was previous considering virtreg liveness only, leading to
incorrect live intervals for reg units when instrs with physreg operands were
moved up.
 

llvm-svn: 163685

"#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)"

No functional change. Update r163339.

llvm-svn: 163653

llvm-svn: 163547

No functional change.

llvm-svn: 163339

We will soon allow virtual register live ranges to overlap regunit live
ranges when the physreg is defined as a copy of the virtreg:

  %EAX = COPY %vreg5
  FOO %vreg5
  BAR %EAX<kill>

There is no real interference since %vreg5 and %EAX have the same value
where they overlap.

This patch prevents addKillFlags from adding virtreg kill flags to FOO
where the assigned physreg is overlapping the virtual register live
range.

llvm-svn: 163335

Fixs PR13719.

llvm-svn: 163107

Based on CR feedback from r162301 and Craig Topper's refactoring in r162347
here are a few other places that could use the same API (& in one instance drop
a Function.h dependency).

llvm-svn: 162367

This option runs LiveIntervals before TwoAddressInstructionPass which
will eventually learn to exploit and update the analysis.

Eventually, LiveIntervals will run before PHIElimination, and we can get
rid of LiveVariables.

llvm-svn: 161270

The 'unused' state of a value number can be represented as an invalid
def SlotIndex. This also exposed code that shouldn't have been looking
at unused value VNInfos.

llvm-svn: 161258

The only real user of the flag was removeCopyByCommutingDef(), and it
has been switched to LiveIntervals::hasPHIKill().

All the code changed by this patch was only concerned with computing and
propagating the flag.

llvm-svn: 161255

The VNInfo::HAS_PHI_KILL is only half supported. We precompute it in
LiveIntervalAnalysis, but it isn't properly updated by live range
splitting and functions like shrinkToUses().

It is only used in one place: RegisterCoalescer::removeCopyByCommutingDef().

This patch changes that function to use a new LiveIntervals::hasPHIKill()
function that computes the flag for a given value number.

llvm-svn: 161254

llvm-svn: 160898

A value number is a PHI def if and only if it begins at a block
boundary. This can be derived from the def slot, a separate flag is not
necessary.

llvm-svn: 160893

This option replaces the existing live interval computation with one
based on LiveRangeCalc.cpp. The new algorithm does not depend on
LiveVariables, and it can be run at any time, before or after leaving
SSA form.

llvm-svn: 160892

llvm-svn: 159030