The tag is updated whenever the live interval union is changed, and it is tested
before using cached information.

llvm-svn: 125224

Print virtual registers numbered from 0 instead of the arbitrary
FirstVirtualRegister. The first virtual register is printed as %vreg0.
TRI::NoRegister is printed as %noreg.

llvm-svn: 123107

interference.

llvm-svn: 122108

This is a three-way interval list intersection between a virtual register, a
live interval union, and a loop. It will be used to identify interference-free
loops for live range splitting.

llvm-svn: 122034

live range splitting around loops guided by register pressure.

So far, trySplit() simply prints a lot of debug output.

llvm-svn: 121918

llvm-svn: 121783

LiveIntervalUnions.

llvm-svn: 121781

llvm-svn: 121410

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

llvm-svn: 121388

references instead.

Similarly, IntervalMap::begin() is almost as expensive as find(), so use find(x)
instead of begin().advanceTo(x);

This makes RegAllocBasic run another 5% faster.

llvm-svn: 121344

llvm-svn: 121319

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

llvm-svn: 121201

llvm-svn: 120504

in favor of the widespread llvm style. Capitalize variables and add
newlines for visual parsing. Rename variables for readability.
And other cleanup.

llvm-svn: 120490

benchmarks hitting an assertion.
Adds LiveIntervalUnion::collectInterferingVRegs.
Fixes "late spilling" by checking for any unspillable live vregs among
all physReg aliases.

llvm-svn: 118701

(retry now that the windows build is green)

llvm-svn: 118630

llvm-svn: 118613

llvm-svn: 118604

handle cases in which a register is unavailable for spill code.
Adds LiveIntervalUnion::extract. While processing interferences on a
live virtual register, reuses the same Query object for each
physcial reg.

llvm-svn: 118423

them, but hopefully we won't. And this is not the right data structure
to do it anyway.

llvm-svn: 117412

llvm-svn: 117384

was found by a GCC warning. ;]

llvm-svn: 117199

framework. It's purpose is not to improve register allocation per se,
but to make it easier to develop powerful live range splitting. I call
it the basic allocator because it is as simple as a global allocator
can be but provides the building blocks for sophisticated register
allocation with live range splitting. 

A minimal implementation is provided that trivially spills whenever it
runs out of registers. I'm checking in now to get high-level design
and style feedback. I've only done minimal testing. The next step is
implementing a "greedy" allocation algorithm that does some register
reassignment and makes better splitting decisions.

llvm-svn: 117174