rewrite instructions for live range splitting.

Still work in progress.

llvm-svn: 109469

The spillers can pluck the analyses they need from the pass reference.

Switch some never-null pointers to references.

llvm-svn: 108969

This is a work in progress. So far we have some basic loop analysis to help
determine where it is useful to split a live range around a loop.

The actual loop splitting code from Splitter.cpp is also going to move in here.

llvm-svn: 108842

non-const.

llvm-svn: 108734

inserted in a MBB, and return an already inserted MI.

This target API change is necessary to allow foldMemoryOperand to call
storeToStackSlot and loadFromStackSlot when folding a COPY to a stack slot
reference in a target independent way.

The foldMemoryOperandImpl hook is going to change in the same way, but I'll wait
until COPY folding is actually implemented. Most targets only fold copies and
won't need to specialize this hook at all.

llvm-svn: 107991

llvm-svn: 107505

llvm-svn: 107503

This allows us to recognize the common case where all uses could be
rematerialized, and no stack slot allocation is necessary.

If some values could be fully rematerialized, remove them from the live range
before allocating a stack slot for the rest.

llvm-svn: 107492

llvm-svn: 107355

llvm-svn: 107351

LocalRewriter::runOnMachineFunction uses this information to mark dead spill
slots.

This means that InlineSpiller now also works for functions that spill.

llvm-svn: 107302

InlineSpiller inserts loads and spills immediately instead of deferring to
VirtRegMap. This is possible now because SlotIndexes allows instructions to be
inserted and renumbered.

This is work in progress, and is mostly a copy of TrivialSpiller so far. It
works very well for functions that don't require spilling.

llvm-svn: 107227