similar to: Inserting MachineInstr's

Hi, I'm trying to emit a conditional move in the ARM backend for a custom intrinsic. Basically, I want to emit the following the following instruction sequence: cmp r0, r1 moveq r2, #1 To implement this, I first emit a compare instruction and then I'm trying to emit the conditional move, which is failing. BuildMI(&MBB, DL, TII->get(ARM::CMPrr))

Hi, Does anyone have any direction for me on testing a back-end pre-emit pass independently of other passes? The pass I'm looking at is a MachineFunctionPass, so the code is already using target-specific instructions. What I'm really looking to do is to see that the pass is correctly converting certain target-specific instructions sequences into other sequences, but I'm unsure how I

Hi, I'm having some trouble wirting an instruction in the X86 backend. I made a new intrinsic and I wrote a custom inserter for my intrinsic in the X86 backend. Everything works fine, except for one instruction that I can't find how to write. I want to add this instruction in one of my machine basic block: mov [rdi], 0 How can I achieve that with the LLVM api? I tried several

I'm trying to define a multiply-accumulate instruction for the LEON processor, a Subtarget of the Sparc target. The documentation for the processor is as follows: === To accelerate DSP algorithms, two multiply&accumulate instructions are implemented: UMAC and SMAC. The UMAC performs an unsigned 16-bit multiply, producing a 32-bit result, and adds the result to a 40-bit accumulator made

I've been looking to see if there's a way to get the instruction below (SMAC) emitted from a higher-level construct, but I'm starting to think this is unrealistic. To do so, I'd have to tie-in two other instructions: Firstly, clearing the ASR18 and Y register somewhere near the start of the method, then copying out the value of these registers somewhere near the end of the method,

Hi, I've discovered a problem on Sparc processors (specifically, LEON, but I suspect but can't verify that it also happens on all Sparc processors). The problem is, or appears to be with using double values in Sparc (32 bit). Specifically, double values are not being loaded into registers correctly within a function using va_args. Only half the value is loaded (i.e. 32, rather than 64

This seems a very natural approach but I probably am having a trouble with the iterator invalidation. However, looking at other peephole optimizers passes, I couldn't see how to do this: #define BUILD_INS(opcode, new_reg, i) \ BuildMI(*MBB, MBBI, MBBI->getDebugLoc(), TII->get(X86::opcode)) \ .addReg(X86::new_reg, kill).addImm(i) for

Hi, I'm trying to implement __builtin_setjmp / __builtin_longjmp for Sparc processors. I think I'm very close, but I can't work out how to issue BuildMI-type instructions to load the address of the recovery location (set in setjmp) into a register using the SETHI / OR combination. I can't see any equivalent code anywhere else in Sparc. I imagine this is similar if I try to make a

The following code is causing me problems in the Sparc back-end and I believe it's related to a lot of issues that I have, so I'd love to work out what I need to do to resolve this. I'm currently not making much headway into it. I'm going to try to simplify this to the core problem I can see and hope I haven't missed anything relevant. The original code I have is as follows:

In many places there is code that looks like: MBBI = next(MBBI); In C++0X there is a std::next that is likely to be in scope when these calls are made. And due to ADL the above call becomes ambiguous: llvm::next or std::next? I recommend: MBBI = llvm::next(MBBI); -Howard

There are 11 BuildMI() functions in MachineInstrBuilder.h including four using the iterator and one using an instruction. But I just don't think that's it. The creation of the new instruction works fine (works fine with OldMI as well) and the new instruction is present in the assembly output. The problem is removing the old instruction correctly. > The loop header needs to be

Hi, I am writing an llvm pass wherein I require to iterate MachineBasicBlocks in reverse. The ilist reverse_iterator is not functioning as expected. Nor is the ilist iterator working in reverse (although -- operator is overloaded to do so). for (MachineFunction::iterator MBBI = mf_->end(), E = mf_->begin();MBBI != E; --MBBI) { MachineBasicBlock *MBB = MBBI;

I made the change to the BuildMI() call. Again, I don't think that matters. #define BUILD_INS(opcode, new_reg, i) \ BuildMI(*MBB, OldMI, MBBI->getDebugLoc(), TII->get(X86::opcode)) \ .addReg(X86::new_reg, kill).addImm(i) I didn't completely understand your other proposed change: ​ for (MachineBasicBlock::iterator MBBI = MBB->begin();

Thanks for the information. I still don't know how do I partition registers into different classes from the virtual registers? For instance, I have the function who which iterates over the instructions, but I don't know how to write the function which returns the different register class. void RAOptimal::Gather(MachineFunction &Fn) { // Gather just iterates over the blocks,

Is there an easy way to obtain all liveout variables of a basic block? Liveins can be found for each MachineBasicBlock, but I can only find liveouts for the whole function, at MachineRegisterInfo. Do I need to find them out manually?

I'm writing a peephole pass and I'm done with the X86_64 instruction level detail work. But I'm having difficulty with the basic block surgery of replacing the old MachineInst. The peephole pass gets called per MachineFunction and then iterates over each MachineBasicBlock and in turn over each MachineInst. When it finds an instruction which should be replaced, it builds a new

On Nov 16, 2009, at 1:43 PM, Dale Johannesen wrote: > > On Nov 14, 2009, at 3:16 PMPST, Howard Hinnant wrote: > >> In many places there is code that looks like: >> >> MBBI = next(MBBI); >> >> In C++0X there is a std::next that is likely to be in scope when these >> calls are made. And due to ADL the above call becomes ambiguous: >>

Because I feel bad for giving a non-answer: An easy way to find if a virtual register is alive after the basic block is to While iterating over the virtual registers - Check to see if the virtual register's "next" value exists outside of the basic block. for instance: std::vector<unsigned> findLiveOut( MachineBasicBlock * mbb ) { std::vector<unsigned> liveout; for(

On Sat, Aug 28, 2010 at 16:20:42 -0400, Jeff Kunkel wrote: > What I need to know is how to access the machine register classes. Also, I > need to know which virtual register is to be mapped into each specific > register class. I assume there is type information on the registers. I need > to know how to access it. MachineRegisterInfo::getRegClass will give you the TargetRegisterClass

So I have a good understanding of what and how I want to do in the abstract sense. I am starting to gain a feel for the code base, and I see that I may have a allocator up and running much faster than I once thought thanks to the easy interfaces. What I need to know is how to access the machine register classes. Also, I need to know which virtual register is to be mapped into each specific