similar to: [LLVMdev] Adding MachineOperands that are not part of MCInstrDesc.

Hello, I'm currently working on a rich disassembler for some ARM/Thumb environment. I wanted to keep most classes independent of the architecture, so I use MCInstrInfo and MCInstrAnalysis to find branch instructions (and other instructions writing to the program counter) and to differentiate between register definitions and uses to track all instructions the branch depends on. This works

Am Mittwoch, 26. September 2012, 11:18:20 schrieb Jakob Stoklund Olesen: > Hi Christoph, > > As you noticed, MCInstrDesc doesn't distinguish between variadic uses and > defs. Since variadic instructions will always require some kind of special > handling, it doesn't seem worthwhile to make the model more detailed. I don't see what makes them so different from other

On Sep 24, 2012, at 6:39 PM, Christoph Grenz <christophg+llvm at grenz-bonn.de> wrote: > Is it possible to extend LLVM to check if 'variable_ops' is in 'ins' and/or > 'outs' in tablegen, so that MCInstrDesc could provide something like > hasVariadicDefs() and hasVariadicUses()? > > That way handling variadic instructions when disassembling would be

Hallo, I worked on how to handle the distinction between variadic defines and uses and my current solution is this: I introduce a new dag item in Instruction called VariadicOperandList, which by default is undefined. It keeps a marker variable_* and all operands which are placeholders for variable lists (like 'reglist' on ARM). I think it's the cleanest solution to keep them in a

Can you elaborate on the fix you are thinking of? I'm not sure what you're thinking should change. On Tue, Nov 19, 2019 at 3:51 PM Quentin Colombet <qcolombet at apple.com> wrote: > It sounds to me that we should fix SDISel to accept both physical and > virtual definitions on variadic instructions. Though I wouldn’t bother > adding the support for implicit virtual

Jonas, At this point, the DFA packetizer models a simple VLIW architecture and does not accommodate multiple stages. That's the reason for the behavior you're seeing. -Anshu --- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation *From:*llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] *On Behalf Of *Jonas

Hi Jonas, > It is interesting to find this in the ARM backend, considering your answer. The ARM backend doesn't use the DFA packetizer. It's only used by Hexagon. At this point, there is no plan to address thisin the DFA packetizer since none of the supported targets needthe functionality. Thanks -Anshu --- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,

Hi, I looked a bit through the mail archives, and found this question answered in Oct 2011 (see below). It is interesting to find this in the ARM backend, considering your answer. Can you give more information about for example is this a temporary deficiency in the DFAPacketizer? What is the IIC_iMOVi itinerary doing below? Thanks, Jonas Thu Oct 6 15:11:25 CDT 2011: Hello Hal. > Is there

To get into more detail, I'm trying to update WebAssembly's `call` instruction. `call` is currently constrained to return one or zero arguments, so in TableGen we have a separate call Instruction for each possible return type. But I need to update calls to return arbitrarily many values of any combination of WebAssembly types, so even if we imposed some reasonable artificial limit like 8

Hi Anshu, Would there be any interest in extending this algorithm to handling more extensive models, such as VLIW scheduling based on FU's and bundle space... ie handle multiple stages ? I might do it and commit, if there is acceptance and guidance... Jonas ________________________________ From: Anshuman Dasgupta [mailto:adasgupt at codeaurora.org] Sent: Tuesday, February 12, 2013 4:47 PM

Hi Quentin, Thanks, that explanation makes sense. I can see that in a normal register machine, implicitly defs must be physical registers. In a stack machine like WebAssembly, though, implicit defs are known to be pushed onto the value stack just like any other defs. Slots on the value stack are represented by virtual registers until stackification, so for WebAssembly we do need the implicit defs

Hi, I have cases of instruction pairs, where one is cheaper 2-address, and the other 3-address. I would like to select the 2-addr instruction during isel, but use the 3-addr instruction to avoid a copy if possible. I find that TwoAddressInstructionPass::isProfitableToConv3Addr() is only checking for the case of a physreg copy, and so leaves the majority of cases as they are (2-address). I

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, 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, > 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 > >

A similar setting occurs with ARM Thumb code which for many instructions has a short 2-address encoding and a longer 3 address form. As far as I know this is done by selecting the 3 address form and rewriting them to 2-address after register allocation where possible. See lib/Target/ARM/Thumb2SizeReduction.cpp. - Matthias > On Sep 29, 2015, at 2:22 PM, Quentin Colombet via llvm-dev

Hi Quentin, I have rerun the test case on a recent commit, so the numbers have changed. There are also now a few more basic blocks very small basic blocks in the function, and therefore there are some slight differences. I tried to go back to earlier commits, without success for some reason... This is however very similar, except that there becomes two COPYs back to sibling value after the loop.

> A node should never be put into the conservatively allocatable list if there is a chance of it spilling. I can understand why the logic of NodeMetadata::isConservativelyAllocatable is necessary for the node to be allocatable, but I have not been able to convince myself this is sufficient, especially when the node degree > available registers. Cheers, Arnaud From:

Hi Jonas, Thanks for your patience. After spending some time looking at the additional output you gave me, I agree that your fix is the right one. I was worried that this problem may arise because we were spilling not real user, but in fact what I thought was the problem is an optimization we could do :). See my comments inlined for a few nitpicks before you commit. Thanks again, -Quentin On

Hi Quentin, I have tried to find a test case for an official target, but failed. It seems to be a rare case. To do it, I added the 'else' clause in the following: ... if (VNI->def == OrigVNI->def) { DEBUG(dbgs() << "orig phi value\n"); SVI->second.DefByOrigPHI = true; SVI->second.AllDefsAreReloads = false; propagateSiblingValue(SVI); continue;