we are only interested in the defs when discovering interferences.

This is a 28% speedup running StrongPHIElimination on 403.gcc.

llvm-svn: 122596

llvm-svn: 122586

when running without the verifier, and I have not yet checked them to see if
the new results are still correct. There are more verifier failures, but they
all seem to be additional occurrences of verifier failures that occur with the
existing PHIElimination pass. There are a few obvious issues with the code:

1) It doesn't properly update the register equivalence classes during copy
insertion, and instead recomputes them before merging live intervals and
renaming registers. I wanted to keep this first patch simple for debugging
purposes, but it shouldn't be very hard to do this.

2) It doesn't mix the renaming and live interval merging with the copy insertion
process, which leads to a lot of virtual register churn. Virtual registers and
live intervals are created, only to later be merged into others. The code should
be smarter and only create a new virtual register if there is no existing
register in the same congruence class.

3) In one place the code uses a DenseMap per basic block, which is unnecessary
heap allocation. There should be an inline storage version of DenseMap.

I did a quick compile-time test of running llc on 403.gcc with and without
StrongPHIElimination. It is slightly slower with StrongPHIElimination, because
the small decrease in the coalescer runtime can't beat the increase in phi
elimination runtime. Perhaps fixing the above performance issues will narrow
the gap.

I also haven't yet run any tests of the quality of the generated code.

llvm-svn: 122582

llvm-svn: 122537

of the problems with my last attempt were in the updating of LiveIntervals
rather than the coalescing itself. Therefore, I decided to get that right first
by essentially reimplementing the existing PHIElimination using LiveIntervals.

It works correctly, with only a few tests failing (which may not be legitimate
failures) and no new verifier failures (at least as far as I can tell, I didn't
count the number per file).

llvm-svn: 122321

StrongPHIElimination.

llvm-svn: 120961

The StrongPHIElimination pass did not work, and nobody has worked on it for two
years.

A rewrite is underway, so I am leaving this shell pass instead of deleting it
completely.

llvm-svn: 120830

Get rid of static constructors for pass registration.  Instead, every pass exposes an initializeMyPassFunction(), which
must be called in the pass's constructor.  This function uses static dependency declarations to recursively initialize
the pass's dependencies.

Clients that only create passes through the createFooPass() APIs will require no changes.  Clients that want to use the
CommandLine options for passes will need to manually call the appropriate initialization functions in PassInitialization.h
before parsing commandline arguments.

I have tested this with all standard configurations of clang and llvm-gcc on Darwin.  It is possible that there are problems
with the static dependencies that will only be visible with non-standard options.  If you encounter any crash in pass
registration/creation, please send the testcase to me directly.

llvm-svn: 116820

perform initialization without static constructors AND without explicit initialization
by the client.  For the moment, passes are required to initialize both their
(potential) dependencies and any passes they preserve.  I hope to be able to relax
the latter requirement in the future.

llvm-svn: 116334

llvm-svn: 115996

Now that PassInfo and Pass::ID have been separated, move the rest of the passes over to the new registration API.

llvm-svn: 111815

llvm-svn: 110460

llvm-svn: 110410

ID member as the sole unique type identifier.  Clean up APIs related to this change.

llvm-svn: 110396

llvm-svn: 108062

The VNInfo.kills vector was almost unused except for all the code keeping it
updated. The few places using it were easily rewritten to check for interval
ends instead.

The two new methods LiveInterval::killedAt and killedInRange are replacements.

This brings us down to 3 independent data structures tracking kills.

llvm-svn: 106905

doesn't have to guess.

llvm-svn: 103194

llvm-svn: 95781

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

llvm-svn: 92596

llvm-svn: 91635

non-landing pad basic block as the successor to a block that ends in an
unconditional jump will cause block folding to remove the added block as a
successor. Thus eventually removing it AND the landing pad entirely. Critical
edge splitting is an optimization, so we can safely turn it off when dealing
with landing pads.

llvm-svn: 91634

This introduces a new pass, SlotIndexes, which is responsible for numbering
instructions for register allocation (and other clients). SlotIndexes numbering
is designed to match the existing scheme, so this patch should not cause any
changes in the generated code.

For consistency, and to avoid naming confusion, LiveIndex has been renamed
SlotIndex.

The processImplicitDefs method of the LiveIntervals analysis has been moved
into its own pass so that it can be run prior to SlotIndexes. This was
necessary to match the existing numbering scheme.

llvm-svn: 85979

VISIBILITY_HIDDEN removal.

llvm-svn: 85043

Chris claims we should never have visibility_hidden inside any .cpp file but
that's still not true even after this commit.

llvm-svn: 85042

llvm-svn: 83255

llvm-svn: 83254

Removed static qualifier from a few index related methods. These methods may require a LiveIntervals instance in future.

llvm-svn: 81374

a new class, MachineInstrIndex, which hides arithmetic details from
most clients. This is a step towards allowing the register allocator
to update/insert code during allocation.

llvm-svn: 81040

llvm-svn: 79832

Modified VNInfo. The "copy" member is now a union which holds the copy for a register interval, or the defining register for a stack interval. Access is via getCopy/setCopy and getReg/setReg.

llvm-svn: 78620

llvm-svn: 77754

as an (index,bool) pair. The bool flag records whether the kill is a
PHI kill or not. This code will be used to enable splitting of live
intervals containing PHI-kills.

A slight change to live interval weights introduced an extra spill
into lsr-code-insertion (outside the critical sections). The test 
condition has been updated to reflect this.

llvm-svn: 75097

llvm-svn: 73634

llvm-svn: 72729

llvm-svn: 57424

llvm-svn: 57046

isReg, etc., from isRegister, etc.

llvm-svn: 57006

Use a multimap rather than a map for holding the list of copies to insert, so we don't lose copies when two of them have
the same source.  I don't know what I was thinking when I wrote this originally.
Note: There's probably a more efficient way to do this, but I need to think about it some more, and about what determinism
guarantees need to be present.

llvm-svn: 56964

llvm-svn: 56893