similar to: [LLVMdev] Debugger for Register Allocation

On Aug 17, 2007, at 4:17 PM, Fernando Magno Quintao Pereira wrote: > > Hi guys, > > I have been using a debugger for my register allocator. The > debugger > happened to be very useful at catching register assignment errors. > I've > put the debugger on-line, if anyone who is working with register > allocation wants to use. The debugger itself has nothing to

Hi guys, I have been using a debugger for my register allocator. The debugger happened to be very useful at catching register assignment errors. I've put the debugger on-line, if anyone who is working with register allocation wants to use. The debugger itself has nothing to do with LLVM, but I've coded a spiller that prints the code in a format that the debugger can read. The

Thank you Chris. I will try to implement the TwoAddress pass to run on machine code. Why it has not been originally implemented to run on machine code? Is there anything that makes it troublesome after RA has been performed? Could you tell me if the transformations below are correct? 1) a := b op c --> a := b --> a := b a := a op c a

Hi Fernando, --- Fernando Magno Quintao Pereira <fernando at cs.ucla.edu> wrote: > > Hi, Roman, > > maybe I can try to answer this. I think that all boils down to > having register to reload spilled values. Ok. That I can follow. > Once a register is spilled, its live range is split into smaller > pieces. These pieces most be contained into registers, and

Thanks again. One more question here: Since the regalloc works once per function, do I stil have access to the Call graph? Just saving information between regalloc passes for different functions may not be enough for my case. I will need to maintain the regalloc info of various passes in the call graph order. Anyways thanks for your inputs. I will get back if I need to learn more. Sanjiv On Nov

Fernando Magno Quintao Pereira wrote: >> I'm not sure about one thing: you assign stack slot to each new register you >> replace the spilled one with. And then you need to allocate physical >> registers to them. Is it possible to assign physical register to the virtual >> one which has a stack slot already? >> > > Yes. The stack slot is the place where the

On Mon, 26 Jun 2006, Fernando Magno Quintao Pereira wrote: > The problem is that, after the TwoAddressInstructionPass is used, the > code is no longer in SSA form, and my register allocator rely on > some SSA properties. I am using the Spiller in VirtRegMap.* to generate > the code, but the incorrect mapping still happens when I invoke the > setReg() method directly on machine

On Mon, 26 Jun 2006, Fernando Magno Quintao Pereira wrote: > Thank you Chris. I will try to implement the TwoAddress pass to run on > machine code. Why it has not been originally implemented to run on > machine code? I'm not sure what you mean. It definitely does run on machine code. > Is there anything that makes it troublesome after RA > has been performed? Do you

Hi, again, I think you can do it in the same way that the other allocators have been coded, i.e extend RA, register the pass and so forth. I am not sure about the best way to pass information among a run of RegAlloc to the other, maybe the other guys in the list could suggest something. Yet, you can always dump it into a file, and read it again, everytime it is necessary. Remember that

On 11/23/07, Fernando Magno Quintao Pereira <fernando at cs.ucla.edu> wrote: > > > Hi, Sanjiv, > > those passes operate on the whole machine function. Each machine > function contains many basic blocks. If a program has many functions, the > register allocator will be called as many times, i.e it does not do > interprocedural allocation. > > best, > >

I'm not sure about one thing: you assign stack slot to each new register you replace the spilled one with. And then you need to allocate physical registers to them. Is it possible to assign physical register to the virtual one which has a stack slot already? On 8/21/06, Fernando Magno Quintao Pereira <fernando at cs.ucla.edu> wrote: > > > > So what addIntervalsToSpills

On Tuesday 04 March 2008 12:16, Chris Lattner wrote: > > Would it be ok to add a getStackPointerRegister method to > > TargetRegisterInfo? > > Why do you need to do this in a register allocator? Typically you want to > refer to abstract frame indices. Wouldn't fernando's debugger use a > similar representation? I don't need it in the allocator. I need it in

Dear guys, I am in need of more of your help. I'm implementing a register allocator, and I am having problems to make it produce correct code. Consider this program here: int main(int argc, char ** argv) { int i, j, sum; i = argv[0][0]; j = argv[0][1]; sum = (i + j) * j; printf("Sum = %d\n", sum); } that maps to this llvm bytecode: entry (0xa785590, LLVM

> I'm not sure about one thing: you assign stack slot to each new register you > replace the spilled one with. And then you need to allocate physical > registers to them. Is it possible to assign physical register to the virtual > one which has a stack slot already? > Yes. The stack slot is the place where the value will be stored in memory, but, when that value is effectively

Who's your advisor? -scooter (aka "Dr. B. Scott Michel, UCLA CS 2004" :-) On Apr 12, 2007, at 4:39 PM, Fernando Magno Quintao Pereira wrote: > >>> And I have a quite fast algo that I believe is simpler than >>> [Budimlic02] >>> and I can share it with you :) >> >> Do you have a paper on this? I'd be interested in seeing it.

Here's issue 48. I'm guessing I'm going to get issue 49 as soon as I hit send... On Fri, Feb 15, 2008 at 3:28 PM, <llvmdev-request at cs.uiuc.edu> wrote: > Send LLVMdev mailing list submissions to > llvmdev at cs.uiuc.edu > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev > or, via

On 7/3/07, Fernando Magno Quintao Pereira <fernando at cs.ucla.edu> wrote: > > what is the best way to implement a swap of floating point registers > in X86? For the integer registers, I am using xchg. Is there a similar > instruction for floating point? FXCH swaps stN with st0, but you'd have to use memory for arbitrary swaps I believe. I have no idea if it's the

On Thu, May 15, 2008 at 5:45 PM, Fernando Magno Quintao Pereira <fernando at cs.ucla.edu> wrote: > > Guys, I need advice in how to handle a problem. > > The problem: > In X86_64, pointers are 64-bit variables, and are stored into 64-bit > registers. However, some pointers are small enough that they can be > represented as 32-bit values. > Is there some way, in

Hi Fernando, On Jul 18, 2007, at 10:57 AM, Fernando Magno Quintao Pereira wrote: > > Dear LLVMers, > > we here in the UCLA compiler's lab have an implementation of a > very > cool register allocator in LLVM. It finds an optimal register > assignment > for the x86 machine, via live range splitting, that is, if it is > possible > to have a register

On Aug 13, 2006, at 11:16 PM, Fernando Magno Quintao Pereira wrote: > > Dear LLVMers, > > I am trying to fold memory operands in the way that is done in > RegAllocLocal.cpp, or in LiveIntervalAnalysis.cpp, but I am getting > errors > that > I don't know how to fix. Could someone tell me which steps should I > take > in order > to correctly fold memory