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a virtual register to eliminate a frame index, it can return that register and the constant stored there to PEI to track. When scavenging to allocate for those registers, PEI then tracks the last-used register and value, and if it is still available and matches the value for the next index, reuses the existing value rather and removes the re-materialization instructions. Fancier tracking and adjustment of scavenger allocations to keep more values live for longer is possible, but not yet implemented and would likely be better done via a different, less special-purpose, approach to the problem. eliminateFrameIndex() is modified so the target implementations can return the registers they wish to be tracked for reuse. ARM Thumb1 implements and utilizes the new mechanism. All other targets are simply modified to adjust for the changed eliminateFrameIndex() prototype. llvm-svn: 83467 |
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| .. | ||
| AsmPrinter | ||
| TargetInfo | ||
| CMakeLists.txt | ||
| Makefile | ||
| MSP430.h | ||
| MSP430.td | ||
| MSP430CallingConv.td | ||
| MSP430InstrFormats.td | ||
| MSP430InstrInfo.cpp | ||
| MSP430InstrInfo.h | ||
| MSP430InstrInfo.td | ||
| MSP430ISelDAGToDAG.cpp | ||
| 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): 0. Implement asmprinting for variables :) 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.