This helper method is too simplistic for RAGreedy.

llvm-svn: 147976

No functional change.

llvm-svn: 147972

The register allocators don't currently support adding reserved
registers while they are running.  Extend the MRI API to keep track of
the set of reserved registers when register allocation started.

Target hooks like hasFP() and needsStackRealignment() can look at this
set to avoid reserving more registers during register allocation.

llvm-svn: 147577

No clients are iterating over interference overlaps.

llvm-svn: 137350

A public interface is no longer needed since RegisterCoalescer is not an
analysis any more.

llvm-svn: 137082

llvm-svn: 136178

asm.c:2:7: error: ran out of registers during register allocation
  asm(""::"r"(0), "r"(1), "r"(2), "r"(3), "r"(4), "r"(5), "r"(6), "r"(7), "r"(8), "r"(9));
        ^

llvm-svn: 134310

remove the analysis group.

llvm-svn: 133899

llvm-svn: 133895

of reserved registers.

Use RegisterClassInfo in RABasic as well. This slightly changes som
allocation orders because RegisterClassInfo puts CSR aliases last.

llvm-svn: 132581

The previous invalidation missed the alias interference caches.

Also add a stats counter for the number of repaired ranges.

llvm-svn: 131133

This can't be just an assertion, users can always write impossible inline
assembly. Such an assembly statement should be included in the error message.

llvm-svn: 131024

On the x86-64 and thumb2 targets, some registers are more expensive to encode
than others in the same register class.

Add a CostPerUse field to the TableGen register description, and make it
available from TRI->getCostPerUse. This represents the cost of a REX prefix or a
32-bit instruction encoding required by choosing a high register.

Teach the greedy register allocator to prefer cheap registers for busy live
ranges (as indicated by spill weight).

llvm-svn: 129864

llvm-svn: 129373

when compiling many small functions.

llvm-svn: 129321

LiveIntervals::findLiveInMBBs has to do a full binary search for each segment.

llvm-svn: 129292

llvm-svn: 129276

llvm-svn: 128935

It is using a trivial rewriter that doesn't know how to insert spill code
requested by the standard spiller.

llvm-svn: 128688

Empty ranges may represent undef values.

llvm-svn: 128144

The live range of a virtual register may change which invalidates the cached
interference information.

llvm-svn: 127772

Live range splitting can create a number of small live ranges containing only a
single real use. Spill these small live ranges along with the large range they
are connected to with copies. This enables memory operand folding and maximizes
the spill to fill distance.

Work in progress with known bugs.

llvm-svn: 127529

This makes it possible to register delegates and get callbacks when the spiller
edits live ranges.

llvm-svn: 127389

llvm-svn: 127388

This is based on the observation that long live ranges are more difficult to
allocate, so there is a better chance of solving the puzzle by handling the big
pieces first. The allocator will evict and split long alive ranges when they get
in the way.

RABasic is still using spill weights for its priority queue, so the interface to
the queue has been virtualized.

llvm-svn: 126259

The rewriter works almost identically to -rewriter=trivial, except it also
eliminates any identity copies.

This makes the new register allocators independent of VirtRegRewriter.cpp which
will be going away at the same time as RegAllocLinearScan.

llvm-svn: 125967

llvm-svn: 125802

llvm-svn: 125789

Registers are not allocated strictly in spill weight order when live range
splitting and spilling has created new shorter intervals with higher spill
weights.

When one of the new heavy intervals conflicts with a single lighter interval,
simply evict the old interval instead of trying to split the heavy one.

The lighter interval is a better candidate for splitting, it has a smaller use
density.

llvm-svn: 125151

createMachineVerifierPass and MachineFunction::verify.

The banner is printed before the machine code dump, just like the printer pass.

llvm-svn: 122113

RegAllocBase::VerifyEnabled.

Run the machine code verifier in a few interesting places during RegAllocGreedy.

llvm-svn: 122107

llvm-svn: 121801

LiveIntervalUnions.

llvm-svn: 121781

llvm-svn: 121604

llvm-svn: 121599

heuristic to reshuffle register assignments when we can't find an
available reg.

llvm-svn: 121388

abstract priority queue interface in subclasses that want to override the
priority calculations.

Subclasses must provide a getPriority() implementation instead.

This approach requires less code as long as priorities are expressable as simple
floats, and it avoids the dangers of defining potentially expensive priority
comparison functions.

It also should speed up priority_queue operations since they no longer have to
chase pointers when comparing registers. This is not measurable, though.

Preferably, we shouldn't use floats to guide code generation. The use of floats
here is derived from the use of floats for spill weights. Spill weights have a
dynamic range that doesn't lend itself easily to a fixpoint implementation.

When someone invents a stable spill weight representation, it can be reused for
allocation priorities.

llvm-svn: 121294

Minor optimization to the use of IntervalMap iterators. They are fairly
heavyweight, so prefer SI.valid() over SI != end().

llvm-svn: 121217

This speeds up RegAllocBasic by 20%, not counting releaseMemory which becomes
way faster.

llvm-svn: 121201

llvm-svn: 121162