will soon be renamed) into their own file.  The new file should not emit
DEBUG output or have other side effects.  The LiveInterval class also now
doesn't know whether its working on registers or some other thing.

In the future we will want to use the LiveInterval class and friends to do
stack packing.  In addition to a code simplification, this will allow us to
do it more easily.

llvm-svn: 15134

Use an explicit LiveRange class to represent ranges instead of an std::pair.
This is a minor cleanup, but is really intended to make a future patch simpler
and less invasive.

Alkis, could you please take a look at LiveInterval::liveAt?  I suspect that
you can add an operator<(unsigned) to LiveRange, allowing us to speed up the
upper_bound call by quite a bit (this would also apply to other callers of
upper/lower_bound).  I would do it myself, but I still don't understand that
crazy liveAt function, despite the comment. :)

Basically I would like to see this:
    LiveRange dummy(index, index+1);
    Ranges::const_iterator r = std::upper_bound(ranges.begin(),
                                                ranges.end(),
                                                dummy);

Turn into:
    Ranges::const_iterator r = std::upper_bound(ranges.begin(),
                                                ranges.end(),
                                                index);

llvm-svn: 15130

the live intervals for some registers.

llvm-svn: 15125

interfere.  Because these intervals have a single definition, and one of them
is a copy instruction, they are always safe to merge even if their lifetimes
interfere.  This slightly reduces the amount of spill code, for example on
252.eon, from:

 12837 spiller               - Number of loads added
  7604 spiller               - Number of stores added
  5842 spiller               - Number of register spills
 18155 liveintervals         - Number of identity moves eliminated after coalescing

to:

  12754 spiller               - Number of loads added
   7585 spiller               - Number of stores added
   5803 spiller               - Number of register spills
  18262 liveintervals         - Number of identity moves eliminated after coalescing

The much much bigger win would be to merge intervals with multiple definitions
(aka phi nodes) but this is not that day.

llvm-svn: 15124

llvm-svn: 15118

llvm-svn: 15115

llvm-svn: 15114

llvm-svn: 15111

llvm-svn: 15108

llvm-svn: 15107

intervals need not be sorted anymore. Removing this redundant step
improves LiveIntervals running time by 5% on 176.gcc.

llvm-svn: 15106

llvm-svn: 15105

compilation of gcc:

* Use vectors instead of lists for the intervals sets
* Use a heap for the unhandled set to keep intervals always sorted and
  makes insertions back to the heap very fast (compared to scanning a
  list)

llvm-svn: 15103

llvm-svn: 15098

the end will reduce erase() runtimes.

llvm-svn: 15093

fortunately, they are easy to handle if we know about them.  This patch fixes
some serious pessimization of code produced by the linscan register allocator.

llvm-svn: 15092

llvm-svn: 15091

llvm-svn: 15089

llvm-svn: 15078

llvm-svn: 15073

compile time for 176.gcc from 5.6 secs to 4.7 secs.

llvm-svn: 15072

llvm-svn: 15069

llvm-svn: 15068

llvm-svn: 15067

stack slots. This is in preparation for the iterative linear scan.

llvm-svn: 15032

llvm-svn: 15031

llvm-svn: 15011

llvm-svn: 15005

is a simple change, but seems to improve code a little.  For example, on
256.bzip2, we went from 75.0s -> 73.33s (2% speedup).

llvm-svn: 15004

llvm-svn: 15003

ask instructions for their parent.

llvm-svn: 14998

llvm-svn: 14997

llvm-svn: 14996

* vreg <-> vreg joining now works, enable it unconditionally when joining
  is enabled (which is the default).
* Fix a serious pessimization of spill code where we were saying that a
  spilled DEF operand was live into the subsequent instruction.  This allows
  for substantially better code when spilling starts to happen.

llvm-svn: 14993

order, causing the inactive list in the linearscan list to get unsorted, which
basically fuxored everything up severely.

These seems to fix the joiner, so with more testing I will enable it by default.

llvm-svn: 14992

llvm-svn: 14991

is sorted.  This is not the case currently, which is causing no end of
problems.

llvm-svn: 14990

Heavily refactor handleVirtualRegisterDef, adding comments and making it more
efficient.  It is also much easier to follow and convince ones self that it is
correct :)

Add -debug output to the joine, showing the result of joining the intervals.

llvm-svn: 14989

remove map that is not needed

llvm-svn: 14988

but make virtreg->virtreg joining stay off by default

llvm-svn: 14916