similar to: [LLVMdev] Reserving registers that depend on spilled code

I have a few pass managers, but only one of them has been initialized with addPassesToEmitCode, how do I find how many passes are added to a function pass manager ? Thank you, Xin On Fri, May 20, 2011 at 1:00 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

Hello, I'm having a curious design conflict related to reserving registers before the register allocator pass is executed with the backend I'm writing. Basically, what I need is to reserve a certain register only if frame space is allocated in the stack, more precisely I'm interested in the case where a register spill occurs. In order to know if a register is spilled the register

Yes, I want the register to be allocatable when there are no stack frames used in the function so it can be used for other purposes. In fact, I looked at how other backends solve this problem, but they are all too conservative by always reserving the register which in my case it is not a good solution because of the performance impact of not having this register available. I find very interesting

Hello Jakob, > Those are some severe constraints on register allocation, but it ought to > be possible anyway. > Indeed, these constraints aren't playing very well with the register allocator :\ > > You may wan't to investigate how RAGreedy::canEvictInterference() is > behaving. > Ok, this is what I've noticed, not sure if it makes sense at all but, regalloc

Hello Jakob, I'm still getting the error, I can give you any other debug info you need. I haven't pasted the regalloc debug info here because it is quite huge, but if you tell me what specific details you need I will include them. Thanks for your help! 2012/7/14 Jakob Stoklund Olesen <stoklund at 2pi.dk> > > On Jul 14, 2012, at 10:09 AM, Borja Ferrer <borja.ferav at

Hello Jakob, Did you get a chance to take a look into this, and if not, can you do it when you get some spare time? Thanks! 2012/12/19 Borja Ferrer <borja.ferav at gmail.com> > We did something like this back when the register allocator couldn't split >> live ranges. >> > > Yes, I remember the isWinToJoinCrossClass() function, removed here: > >

Hello, Is there a way to determine before register allocation if a virtual reg is mapped to the lo or hi part of a piece of a value? Basically i need to tell the register allocator to use a certain set of registers for the lo part and others for the hi part, so in order to do this i would have to know if the data value was expanded into smaller pieces and which piece is each one. Additionally,

On Nov 28, 2011, at 3:39 PM, Borja Ferrer wrote: > Hello, > > I'm having a curious design conflict related to reserving registers before the register allocator pass is executed with the backend I'm writing. Basically, what I need is to reserve a certain register only if frame space is allocated in the stack, more precisely I'm interested in the case where a register spill

Hello, I'm getting a machine verifier error after introducing the earlyclobber constraint to some instructions where the src and dest regs can't be the same. The offending instruction pattern is this one: let canFoldAsLoad = 1, isReMaterializable = 1, Constraints = "@earlyclobber $dst" in def LDDWRdPtrQ : Inst<(outs DREGS:$dst), (ins memri:$src),

Ok, I've found that marking tiny live intervals as not spillable inside VirtRegAuxInfo::CalculateWeightAndHint is not playing nicely with very constrained regclasses, in my case a regclass composed of only one register. As a workaround, instead of marking them as not spillable, I've marked them with a very high spill cost and the regalloc is able to compile the function with good code

On Jan 7, 2013, at 4:58 AM, Borja Ferrer <borja.ferav at gmail.com> wrote: > Hello Jakob, > > Did you get a chance to take a look into this, and if not, can you do it when you get some spare time? It's not likely I'll have time to look at this in the near future. I'd recommend you do it yourself. /jakob > 2012/12/19 Borja Ferrer <borja.ferav at gmail.com>

Hello everybody, During the past week I've kept looking for a solution to this but i couldn't find one, is there really a way to get this type of information or some workaround? Thanks. 2010/12/22 Borja Ferrer <borja.ferav at gmail.com> > Hello, > > Is there a way to determine before register allocation if a virtual reg is > mapped to the lo or hi part of a piece of a

So I've been designing an experimental 6502 backend for LLVM. Link: <https://github.com/beholdnec/llvm-m6502> The 6502 only has a few registers, one accumulator and two indexes, none of which are large enough to hold an absolute pointer. Because of this, the backend really tests the power of LLVM's register allocator (RA). I've made a change to the RA that might be of interest

Jakob, one more hint, I've placed some asserts around the code you added and noticed that the InlineSpiller::insertReload() function is not being called. 2012/7/14 Borja Ferrer <borja.ferav at gmail.com> > Hello Jakob, > > I'm still getting the error, I can give you any other debug info you need. > I haven't pasted the regalloc debug info here because it is quite

Hello everbody, This is my first email to the list, and hope to write more as i get more involved in LLVM. I'm currently writing a backend for a 8 bit microcontroller, and i have arrived to a point where i need to take a design decision in order to continue the development. Some background information: The microcontroller only has 8bit registers, however it has some special instructions that

Hello Jakob, I think I've found something interesting that may help you get a better idea of what's going on. While looking at the debug info I noticed that the coalescer was removing lots of copies that could help the allocator make more cross class copies. As a test, I disabled the join-liveintervals option in the coalescer which gave me the surprise of making the regalloc succeed. To

Hello, while testing trivial functions in my backend i noticed a suboptimal way of assigning regs that had the following pattern, consider the following function: typedef unsigned short t; t foo(t a, t b) { t a4 = b^a^18; return a4; } Argument "a" is passed in R15:R14 and argument "b" is passed in R13:R12, the return value is stored in R15:R14. Producing the

On Jan 9, 2013, at 10:46 AM, Borja Ferrer <borja.ferav at gmail.com> wrote: > Ok, I've found that marking tiny live intervals as not spillable inside VirtRegAuxInfo::CalculateWeightAndHint is not playing nicely with very constrained regclasses, in my case a regclass composed of only one register. > As a workaround, instead of marking them as not spillable, I've marked them

On Jul 14, 2012, at 10:09 AM, Borja Ferrer <borja.ferav at gmail.com> wrote: > Hello, > > I'm getting a machine verifier error after introducing the earlyclobber constraint to some instructions where the src and dest regs can't be the same. The offending instruction pattern is this one: > > let canFoldAsLoad = 1, > isReMaterializable = 1, > Constraints =

Hello, I'm adding a new function attribute in clang and llvm for a backend I'm writing that treats prolog and epilogue code in a special way inside interrupt handlers, similar to what naked does. One way I've seen to do this is to add a new attribute type in Attributes.h, however to me it feels bad to add a target dependent attribute into this place which is very target independent.