use before rematerializing the load.

This allows us to produce:

    addps	LCPI0_1(%rip), %xmm2

Instead of:

    movaps	LCPI0_1(%rip), %xmm3
    addps	%xmm3, %xmm2

Saving a register and an instruction. The standard spiller already knows how to
do this.

llvm-svn: 122133

llvm-svn: 118661

give them individual stack slots once the are actually spilled.

llvm-svn: 117945

llvm-svn: 117677

the remainder register.

Example:

bb0:
  x = 1
bb1:
  use(x)
  ...
  x = 2
  jump bb1

When x is isolated in bb1, the inner part breaks into two components, x1 and x2:

bb0:
  x0 = 1
bb1:
  x1 = x0
  use(x1)
  ...
  x2 = 2
  x0 = x2
  jump bb1

llvm-svn: 117408

llvm-svn: 116951

All registers created during splitting or spilling are assigned to the same
stack slot as the parent register.

When splitting or rematting, we may not spill at all. In that case the stack
slot is still assigned, but it will be dead.

llvm-svn: 116546

splitting or spillling, and to help with rematerialization.

Use LiveRangeEdit in InlineSpiller and SplitKit. This will eventually make it
possible to share remat code between InlineSpiller and SplitKit.

llvm-svn: 116543