similar to: [LLVMdev] Multiple connected components in live interval

Hi Jonas, Could you file a PR with your test case please? Thanks, -Quentin > On Apr 16, 2015, at 3:50 PM, Andrew Trick <atrick at apple.com> wrote: > >> >> On Apr 16, 2015, at 6:58 AM, Jonas Paulsson <jonas.paulsson at ericsson.com <mailto:jonas.paulsson at ericsson.com>> wrote: >> >> Hi, >> >> I have come across a csmith generated

Hi Jonas, When is the MachineVerifier complaining? I mean after which pass? Thanks, -Quentin > On Apr 17, 2015, at 7:17 AM, Jonas Paulsson <jonas.paulsson at ericsson.com> wrote: > > Hi, > > thanks for answering, but the COPY is there already from after isel. It is a copy of a subreg, after a a call returning 64 bits. > > call

Hi Jonas, > On Apr 20, 2015, at 4:03 AM, Jonas Paulsson <jonas.paulsson at ericsson.com> wrote: > > Hi Quentin, > > After Simple Register Coalescing. Is the code you have pasted with the PHIs feed to the register coalescer? I am trying to understand the setting to help debugging the problem. Also, what does -debug-only=regalloc tell you? Thanks, -Quentin > >

Hi, I don't know if my llvm ir code is faulty, or if I spot a bug in the RegisterCoalescing Pass, so I'm posting my issue on the ML. Shader and print-before-all dump are given below. The interessing part is the vreg6/vreg48 reduction : before RegCoalescing, the machine code is : // BEFORE LOOP ... Some COPYs.... 400B%vreg47<def> = COPY %vreg2<kill>; R600_Reg32:%vreg47,%vreg2

On Jun 13, 2012, at 1:15 PM, Sergei Larin <slarin at codeaurora.org> wrote: > Andy, > > You are probably right here – look at this – before phi elimination this code looks much more sane: > > # *** IR Dump After Live Variable Analysis ***: > # Machine code for function push: SSA > Function Live Outs: %R0 > > BB#0: derived from LLVM BB %entry >

Hi, I have a question related to pre-RA scheduling and spill of registers. I'm writing a backend for two operands instructions set, so FPU operations result have implicit destination. For example, the result of FMUL_A_oo is implicitly the register FA_ROUTMUL. I have defined FPUaROUTMULRegisterClass containing only FA_ROUTMUL. During the instruction lowering, in order to avoid frequent spill

Hi, Is it intended that in some cases it is necessary to use "-disable-cross-class-join" to be sure the resulting code is ok? I have several cases where cross class joins are carried out that makes the code turn out illegal, because the "new" register class is not allowed in all instructions where it is now used. For example, by joining %vreg4, %vreg7 and %vreg9 the

On Jun 13, 2012, at 10:49 AM, Sergei Larin <slarin at codeaurora.org> wrote: > So if this early exit is taken: > > // SSA defs do not have output/anti dependencies. > // The current operand is a def, so we have at least one. > if (llvm::next(MRI.def_begin(Reg)) == MRI.def_end()) > return; > > we do not ever get to this point: > >

Ok, after a long detour I am back to where I have started. I think there is a problem at dep DAG construction. Let me try to convince you. Here is the C code we are dealing with: push () { struct xx_stack *stack, *top; for (stack = xx_stack; stack; stack = stack->next) top = stack; yy_instr = top->first; } If the loop never iterates, "top" will have

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

Sergei, Absolutely right, the copy/ldriw should not be reordered. I was attempting to explain that I consider it a phi-elimination bug, not a DAG builder bug. Liveness will also have problems with this code in the long run. To avoid confusion, I filed PR13112: Phi elimination generates uninitialized vreg uses, and disabled the SSA check until its fixes in r158461. However, your C code is also

On Jan 19, 2012, at 2:16 AM, Patrik Hägglund <patrik.h.hagglund at ericsson.com> wrote: > Is it intended that in some cases it is necessary to use > "-disable-cross-class-join" to be sure the resulting code is ok? No. > I have several cases where cross class joins are carried out that makes > the code turn out illegal, because the "new" register class is

Andy, You are probably right here - look at this - before phi elimination this code looks much more sane: # *** IR Dump After Live Variable Analysis ***: # Machine code for function push: SSA Function Live Outs: %R0 BB#0: derived from LLVM BB %entry %vreg5<def> = IMPLICIT_DEF; IntRegs:%vreg5 %vreg4<def> = TFRI_V4 <ga:@xx_stack>; IntRegs:%vreg4

I've inherited some target code, but there is no SELECT lowering in my target. But somewhere/somehow SELECT is being transformed into a predicated move. I've traced SELECT everywhere in Codegen/SelectionDAG. Any ideas on tracking this down to the point in Codegen lowering/dag-conversion to a predicated series? Again, I do not have a lowering rule in my target for SELECT. If I do a IR

On Wed, Feb 8, 2017 at 6:21 PM, Wei Mi <wmi at google.com> wrote: > I have an issue that I've been wrestling with for quite some time and I'm > hoping that someone with a deeper understanding of the register allocator > can help me with. > > Namely, I am trying to teach RA to split a live range rather than > allocating a CSR. I've attempted a very large number

I have an issue that I've been wrestling with for quite some time and I'm hoping that someone with a deeper understanding of the register allocator can help me with. Namely, I am trying to teach RA to split a live range rather than allocating a CSR. I've attempted a very large number of tweaks to the costs (both existing and experimental ones that I've added). However, despite all

Hi, I've been looking at the Machine Scheduler on Power PC. I am looking only at the pre-RA machine scheduler and I am running it in the default bi-directional mode (so, both top down and bottom up queues are considered). I've come across an example where the scheduler picks a poor ordering for the instructions which results in very high register pressure which results in spills.

On Sep 18, 2012, at 1:45 PM, Bjorn De Sutter <bjorn.desutter at elis.ugent.be> wrote: > I am working on a backend for a CGRA architecture with advanced predicate support (as on EPIC machines and as first used in the OpenIMPACT compiler). Until last month, the backend was working fine, but since the r161643 commit by stoklund, my backend doesn't work anymore. I think I noticed some

Hi Ehsan, In some cases modulo scheduling will insert copy instruction that end up as real copies in the final code. It unavoidable in some cases. For example, let's say a instruction defining a value is scheduled in the first iteration, but one of its uses is scheduled two iterations later. In this case, the kernel needs to create a copy because there will be two values live in the

> > PHIElim and TwoAddress passes leave SSA form. > May be a missed something in your code but %vreg48 seems to be there > after PHI elimination. PHIElim tags those kind of registers as being > PHIJoin regs, updating LiveVariables pass, so the regcoalescer is aware > of them (some SSA info is still alive but the reg coalescer will > invalidate that information after