HandlePHINodesInSuccessorBlocks that works FastISel-style. This
allows PHI nodes to be updated correctly while using FastISel.

This also involves some code reorganization; ValueMap and
MBBMap are now members of the FastISel class, so they needn't
be passed around explicitly anymore. Also, SelectInstructions
is changed to SelectInstruction, and only does one instruction
at a time.

llvm-svn: 55746

llvm-svn: 55693

llvm-svn: 55685

Let tblgen only generate fastisel routines, not the class definition. This makes it easier for targets to define its own fastisel class.

llvm-svn: 55679

llvm-svn: 55545

llvm-svn: 55512

and use it in FastISelEmitter.cpp, and make FastISel
subtarget aware. Among other things, this lets it work
properly on x86 targets that don't have SSE, where it
successfully selects x87 instructions.

llvm-svn: 55156

llvm-svn: 55011