llvm-6502/lib/Target/MSP430
Dan Gohman eeb3a00b84 Change SelectCode's argument from SDValue to SDNode *, to make it more
clear what information these functions are actually using.

This is also a micro-optimization, as passing a SDNode * around is
simpler than passing a { SDNode *, int } by value or reference.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92564 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05 01:24:18 +00:00
..
AsmPrinter
TargetInfo
CMakeLists.txt
Makefile
MSP430.h
MSP430.td
MSP430CallingConv.td
MSP430InstrFormats.td
MSP430InstrInfo.cpp
MSP430InstrInfo.h
MSP430InstrInfo.td
MSP430ISelDAGToDAG.cpp Change SelectCode's argument from SDValue to SDNode *, to make it more 2010-01-05 01:24:18 +00:00
MSP430ISelLowering.cpp
MSP430ISelLowering.h
MSP430MachineFunctionInfo.h
MSP430MCAsmInfo.cpp
MSP430MCAsmInfo.h
MSP430RegisterInfo.cpp
MSP430RegisterInfo.h
MSP430RegisterInfo.td
MSP430Subtarget.cpp
MSP430Subtarget.h
MSP430TargetMachine.cpp
MSP430TargetMachine.h
README.txt

//===---------------------------------------------------------------------===//
// MSP430 backend.
//===---------------------------------------------------------------------===//

DISCLAIMER: Thid backend should be considered as highly experimental. I never
seen nor worked with this MCU, all information was gathered from datasheet
only. The original intention of making this backend was to write documentation
of form "How to write backend for dummies" :) Thes notes hopefully will be
available pretty soon.

Some things are incomplete / not implemented yet (this list surely is not
complete as well):

1. Verify, how stuff is handling implicit zext with 8 bit operands (this might
be modelled currently in improper way - should we need to mark the superreg as
def for every 8 bit instruction?).

2. Libcalls: multiplication, division, remainder. Note, that calling convention
for libcalls is incomptible with calling convention of libcalls of msp430-gcc
(these cannot be used though due to license restriction).

3. Implement multiplication / division by constant (dag combiner hook?).

4. Implement non-constant shifts.

5. Implement varargs stuff.

6. Verify and fix (if needed) how's stuff playing with i32 / i64.

7. Implement floating point stuff (softfp?)

8. Implement instruction encoding for (possible) direct code emission in the
future.

9. Since almost all instructions set flags - implement brcond / select in better
way (currently they emit explicit comparison).

10. Handle imm in comparisons in better way (see comment in MSP430InstrInfo.td)

11. Implement hooks for better memory op folding, etc.