Stop depending on the LiveIntervalUnions in RegAllocBase, they are about
to be removed.

The changes are mostly replacing register alias iterators with regunit
iterators, and querying LiveRegMatrix instrad of RegAllocBase.

InterferenceCache is converted to work with per-regunit
LiveIntervalUnions, and it checks fixed regunit interference separately,
using the fixed live intervals provided by LiveIntervalAnalysis.

The local splitting helper calcGapWeights() is also considering fixed
regunit interference which is kept on the side now.

llvm-svn: 158867

No functional change intended.

Sorry for the churn. The iterator classes are supposed to help avoid
giant commits like this one in the future. The TableGen-produced
register lists are getting quite large, and it may be necessary to
change the table representation.

This makes it possible to do so without changing all clients (again).

llvm-svn: 157854

llvm-svn: 152001

Pretend that regmask interference ends at the 'dead' slot, even when
there is other interference ending at the 'reg' slot of the same
instruction.

llvm-svn: 150531

It can be necessary to detach a register mask pointer from its
MachineOperand. This method is convenient for checking clobbered
physregs on a detached bitmask pointer.

llvm-svn: 150261

This makes global live range splitting behave identically with and
without register mask operands.

This is not necessarily the best way of using register masks for live
range splitting.  It would be more efficient to first split global live
ranges around calls (i.e., register masks), and reserve the fine grained
per-physreg interference guidance for global live ranges that do not
cross calls.

For now the goal is to produce identical assembly when enabling register
masks.

llvm-svn: 150259

llvm-svn: 148143

llvm-svn: 148103

They always report 'no interference'.

llvm-svn: 135843

Original commit message:

Count references to interference cache entries.

Each InterferenceCache::Cursor instance references a cache entry. A
non-zero reference count guarantees that the entry won't be reused for a
new register.

This makes it possible to have multiple live cursors examining
interference for different physregs.

The total number of live cursors into a cache must be kept below
InterferenceCache::getMaxCursors().

Code generation should be unaffected by this change, and it doesn't seem
to affect the cache replacement strategy either.

llvm-svn: 135130

llvm-svn: 135122

Each InterferenceCache::Cursor instance references a cache entry. A
non-zero reference count guarantees that the entry won't be reused for a
new register.

This makes it possible to have multiple live cursors examining
interference for different physregs.

The total number of live cursors into a cache must be kept below
InterferenceCache::getMaxCursors().

Code generation should be unaffected by this change, and it doesn't seem
to affect the cache replacement strategy either.

llvm-svn: 135121

This doesn't require seeking in the live interval union, so it is very cheap.

llvm-svn: 129187

llvm-svn: 129081

When the greedy register allocator is splitting multiple global live ranges, it
tends to look at the same interference data many times. The InterferenceCache
class caches queries for unaltered LiveIntervalUnions.

llvm-svn: 128764