similar to: [LLVMdev] mips16 puzzle

Actually, SP is already not in the mips 16 register class but there is some C++ code that is common to mips32, mips64 and mips16 that is wanting to use SP. It's kind of awkward but does work except in this case of load/store haflword and byte to stack objects. Maybe I'm shooting myself in the foot there. I don't know that code too well so maybe I need to look into it. There are

Reed, It's not clear to me that you need to do anything special here. If you define your MIPS16 register class as not containing SP, then any MIPS16 instructions that get selected and want to read from SP should get a COPY inserted from SP to a MIPS16 vreg. The coalescer should, ideally, get rid of extraneous copies for you. --Owen On Sep 20, 2012, at 10:48 PM, Reed Kotler <rkotler at

On Sep 20, 2012, at 11:44 PM, Reed Kotler <rkotler at mips.com> wrote: > Actually, SP is already not in the mips 16 register class but there is some C++ code that is common to mips32, mips64 and mips16 that is wanting to use SP. It's kind of awkward but does work except in this case of load/store haflword and byte to stack objects. > ARM has a similar problem. The InstrInfo

We already divided out our classes as you did for ARM. The problem here is that we have a store/load byte/halfword to/from a Frame object. We know at that time that it's not going to be possible to store it using SP because there is only such instructions for store/load of a word. What we would want to do is to move SP into a Mips 16 register and then do a indexed load/store off of that

Ok. That's a somewhat different problem, then. Devil will be in the details of what you want to do. A few options. First is to always have a standard frame pointer register available and reference off of that. Caveat: dynamic stack realignment and vararrays muck with that more than a bit. Second is what gcc is doing and reserve a register just for this in addition to the frame register.

Turned out to be a rather simple fix. Just copied SP to a virtual register in the beginning of the function. Then added an extra operand to the DAGs with stack reference load/store, with the extra operand equal to this virtual register if the Parent of the address is a LOAD/STORE of an 8 or 16 bit quantity. It worked fine. When needed SP got copied to a mips 16 register and when the SP alias

On Mon, Jan 7, 2013 at 4:16 PM, reed kotler <rkotler at mips.com> wrote: > On 01/04/2013 07:45 PM, Eli Friedman wrote: >> >> On Fri, Jan 4, 2013 at 6:28 PM, reed kotler <rkotler at mips.com> wrote: >>> >>> On 01/04/2013 06:08 PM, Eli Friedman wrote: >>>> >>>> On Fri, Jan 4, 2013 at 4:08 PM, reed kotler <rkotler at mips.com>

On 01/04/2013 07:45 PM, Eli Friedman wrote: > On Fri, Jan 4, 2013 at 6:28 PM, reed kotler <rkotler at mips.com> wrote: >> On 01/04/2013 06:08 PM, Eli Friedman wrote: >>> On Fri, Jan 4, 2013 at 4:08 PM, reed kotler <rkotler at mips.com> wrote: >>>> I'm working on mips16 hard float which at a first approximation is just >>>> soft

I'm working on mips16 hard float which at a first approximation is just soft float but calls different library routines. Those different library routines are just an implementation (in mips32 mode) of soft float using mips32 hardware instructions. This part is already done. (mips16 mode has no floating point instructions). The next level of this that I am working on now is the ability to

On Fri, Jan 4, 2013 at 6:28 PM, reed kotler <rkotler at mips.com> wrote: > On 01/04/2013 06:08 PM, Eli Friedman wrote: >> >> On Fri, Jan 4, 2013 at 4:08 PM, reed kotler <rkotler at mips.com> wrote: >>> >>> I'm working on mips16 hard float which at a first approximation is just >>> soft >>> float but calls different library

On 01/04/2013 06:08 PM, Eli Friedman wrote: > On Fri, Jan 4, 2013 at 4:08 PM, reed kotler <rkotler at mips.com> wrote: >> I'm working on mips16 hard float which at a first approximation is just soft >> float but calls different library routines. Those different library routines >> are just an implementation (in mips32 mode) of soft float using mips32 >>

On Fri, Jan 4, 2013 at 4:08 PM, reed kotler <rkotler at mips.com> wrote: > I'm working on mips16 hard float which at a first approximation is just soft > float but calls different library routines. Those different library routines > are just an implementation (in mips32 mode) of soft float using mips32 > hardware instructions. This part is already done. (mips16 mode has no

For example: /home/rkotler/llvm/install/bin/llc -mcpu=mips16 hf16_2.ll -march=mipsel -relocation-model=pic -o hf16_2.s -O3 -mips16-hard-float -soft-float On 01/04/2013 07:45 PM, Eli Friedman wrote: > On Fri, Jan 4, 2013 at 6:28 PM, reed kotler <rkotler at mips.com> wrote: >> On 01/04/2013 06:08 PM, Eli Friedman wrote: >>> On Fri, Jan 4, 2013 at 4:08 PM, reed kotler

1. mips16 instructions (except for move) have a different encoding from normal mips32 instructions for two registers. however in the move register 2 operand instruction, one register takes the mips16 encoding and the other the mips32 encoding (so that gives mips16 access to the full register set). how does one deal with multiple encodings of the same register? can you change it on an

I'm working on the mips16. Mips16 is a mode of the Mips32 (or Mips64) processor. For the most part, it is a compressed form of the MIPS32 instruction set, though not all instructions are supported. Most of the same opcodes and formats are present though sometimes with some restriction. (The micro mips architecture is a true 16 bit compressed form of MIps32 though also with some

We are starting to look at the mips16 and micro mips ports. There are various design issues that people may have some good input on. Especially in how to structure the TD files and other optimizer issues. Mips16 is sort of like thumb and Micro Mips like thumb2 as far as I understand. Mips16 or Micro Mips can live inside of either MIPS32 or MIPS64. In gcc, it's possible using attributes to

Hi Bob, This has turned out to be what appears to be a very obscure binutils bug. I'm working on a test case for it now. I have a patch for Mips16 llvm which works around the issue for now. In general, pure risc architectures have no pity for compiler and toolchain developers. Mips16 is way more extreme in this way than mips32. In mips32, there is no PC register or PC relative

On Jan 24, 2012, at 1:46 AM, Reed Kotler wrote: > Mips16 is a mode of the Mips32 (or Mips64) processor. For the most part, > it is a compressed form of the MIPS32 instruction set, though not all > instructions are supported. Most of the same opcodes and formats are > present though sometimes with some restriction. (The micro mips > architecture is a true 16 bit compressed form

So what I realized is that you can't use the simple scavenger trick where you create the virtual register and use the more advanced features. This is because you can't call forward() in any form if there are virtual registers being used by any of the instructions in the basic block. This will cause forward to fail. Maybe this is a bug in forward() On 02/05/2013 02:51 PM, Reed Kotler

On Fri, Jan 20, 2012 at 1:59 PM, reed kotler <rkotler at mips.com> wrote: > We are starting to look at the mips16 and micro mips ports. > > There are various design issues that people may have some good input on. > Especially in how to structure the TD files and other optimizer issues. > > Mips16 is sort of like thumb and Micro Mips like thumb2 as far as I > understand.