2) live-outs.

Previously the post-RA schedulers completely ignore these dependencies since
returns, branches, etc. are all scheduling barriers. This patch model the
latencies between instructions being scheduled and the barriers. It also
handle calls by marking their register uses.

llvm-svn: 117193

llvm-svn: 117192

of all predecessors.

llvm-svn: 117191

llvm-svn: 117189

llvm-svn: 117188

llvm-svn: 117187

llvm-svn: 117186

llvm-svn: 117185

llvm-svn: 117183

llvm-svn: 117180

llvm-svn: 117177

llvm-svn: 117176

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

llvm-svn: 117173

llvm-svn: 117172

llvm-svn: 117171

llvm-svn: 117170

When a block has exactly two uses and the register is both live-in and live-out,
don't isolate the block. We would be inserting two copies, so we haven't really
made any progress.

If the live-in and live-out values separate into disconnected components after
splitting, we would be making progress. We can't detect that for now.

llvm-svn: 117169

llvm-svn: 117166

llvm-svn: 117165

Apple builds.  Radar 8585383.

llvm-svn: 117164

llvm-svn: 117158

llvm-svn: 117157

llvm-svn: 117156

llvm-svn: 117155

llvm-svn: 117154

llvm-svn: 117151

llvm-svn: 117145

An exit block with a critical edge must only have predecessors in the loop, or
just before the loop. This guarantees that the inserted copies in the loop
predecessors dominate the exit block.

llvm-svn: 117144

llvm-svn: 117143

llvm-svn: 117134

llvm-svn: 117133

llvm-svn: 117132

llvm-svn: 117131

llvm-svn: 117130

llvm-svn: 117128

llvm-svn: 117126

llvm-svn: 117124

llvm-svn: 117122

llvm-svn: 117121