llvm-svn: 11721

llvm-svn: 11719

llvm-svn: 11704

Also make it less aggressive as the current implementation breaks in
some cases.

llvm-svn: 11696

llvm-svn: 11687

llvm-svn: 11676

llvm-svn: 11675

llvm-svn: 11674

1. LiveIntervals now implement a 4 slot per instruction model. Load,
   Use, Def and a Store slot. This is required in order to correctly
   represent caller saved register clobbering on function calls,
   register reuse in the same instruction (def resues last use) and
   also spill code added later by the allocator. The previous
   representation (2 slots per instruction) was insufficient and as a
   result was causing subtle bugs.

2. Fixes in spill code generation. This was the major cause of
   failures in the test suite.

3. Linear scan now has core support for folding memory operands. This
   is untested and not enabled (the live interval update function does
   not attempt to fold loads/stores in instructions).

4. Lots of improvements in the debugging output of both live intervals
   and linear scan. Give it a try... it is beautiful :-)

In summary the above fixes all the issues with the recent reserved
register elimination changes and get the allocator very close to the
next big step: folding memory operands.

llvm-svn: 11654

llvm-svn: 11575

llvm-svn: 11574

llvm-svn: 11516

llvm-svn: 11476

std::numeric_limits<float>::max() for weighting preallocated
intervals.

llvm-svn: 11427

llvm-svn: 11393

ilist of MachineInstr objects. This allows constant time removal and
insertion of MachineInstr instances from anywhere in each
MachineBasicBlock. It also allows for constant time splicing of
MachineInstrs into or out of MachineBasicBlocks.

llvm-svn: 11340

llvm-svn: 11283

slots each. As a concequence they get numbered as 0, 2, 4 and so
on. The first slot is used for operand uses and the second for
defs. Here's an example:

0: A = ...
2: B = ...
4: C = A + B ;; last use of A

The live intervals should look like:

A = [1, 5)
B = [3, x)
C = [5, y)

llvm-svn: 11141

access. Rather we only have to do it on the creation of the interval.

llvm-svn: 11135

outside of loops = 0.

llvm-svn: 11085

llvm-svn: 11057

llvm-svn: 11054

llvm-svn: 11048

llvm-svn: 11047

MRegisterInfo::isVirtualRegister.

llvm-svn: 11045

llvm-svn: 11040

llvm-svn: 11038

any test cases :-)

llvm-svn: 11032

of a linear search to find the first range for comparisons. This cuts
down the linear scan register allocator running time by a factor of 3
in 254.perlbmk and by a factor of 2.2 in 176.gcc.

llvm-svn: 11030

llvm-svn: 11029

Simplification of LiveIntervals::Interval::overlaps() and addition of
examples to overlaps() and liveAt() to make them clearer.

llvm-svn: 11028

when joining we need to check if we overlap with the second interval
or any of its aliases.

Also make joining intervals the default.

llvm-svn: 10973

is a move between two registers, at least one of the registers is
virtual and the two live intervals do not overlap.

This results in about 40% reduction in intervals, 30% decrease in the
register allocators running time and a 20% increase in peephole
optimizations (mainly move eliminations).

The option can be enabled by passing -join-liveintervals where
appropriate.

llvm-svn: 10965

llvm-svn: 10957

llvm-svn: 10956

llvm-svn: 10893

when we join intervals and one of the two will need to be removed.

llvm-svn: 10892

llvm-svn: 10847

LiveIntervals::Interval::liveAt. Both were considering the live ranges
closed in the end, when they are actually open.

llvm-svn: 10835

be dead at the defining instruction but can only be killed in
subsequent ones.

llvm-svn: 10833