similar to: GlobalISel round table follow up: register bank select

Hi Quentin, thanks for picking up the conversation! > I think we should step back and check what we want before investing any time in some rewrite. That is a very fair point and I might have been getting ahead of myself in my last email. What I would like to see from RegBankSelect is to produce the mapping with the overall lowest cost. Keeping track of all different combinations of

Hi Quentin, Am 08.10.20 um 21:17 schrieb Quentin Colombet: > Hi Dominik, > >> On Oct 8, 2020, at 5:03 AM, Dominik Montada >> <dominik.montada at hightec-rt.com >> <mailto:dominik.montada at hightec-rt.com>> wrote: >> >> Hi Quentin, >> >> thanks for picking up the conversation! >> >> > I think we should step back and

Hi Quentin, thank you for the reply! I have a couple more questions that came up when I tried to implement this today. I hope you can help me out with this again! Am 09.03.20 um 23:31 schrieb Quentin Colombet: > I would expect that you could create a register class and register > bank for the special register. That way you have something to map to > when you do register bank select.

Hi Quentin, thank you for the reply! This clears up a lot of the questions I was having. It seems like we should definitely invest some time in rewriting some of our legalization rules then! I also posted some questions further down below. I would appreciate getting your opinion on them. > Hi Dominik, > > I’ll do a brief reply here and if you want more information we can talk further

Hi, GlobalISel currently drops all type information relating to the integer/FP distinction during the IR translation pass, as the LLT types only represent whether a value is a scalar/vector/pointer and it’s size/shape. To compensate, later passes use the FP operations on those values to guess what kind of value is being stored within that virtual register. This means that i32/float loads get

I don’t think bfloat should be handled this way. What Amara is suggesting is an optimization, i.e., if we drop the information we are still correct. With bfloat, if we do an operation on float16 instead of bfloat16 this is a correctness problem. So that means that either we need to have new opcodes for bfloat or we need to carry around the floating point type in MIR. I think it would be more

Hi, I've spent some time playing around with GlobalISel on the AMDGPU target, and I was wondering if there is any reason to have RegisterBankInfo::getInstrAlternativeMappings() and RegisterBankInfo::getInstrMapping() as separate functions. Could we instead replace these two functions with just one: RegisterBankInfo::getInstrMappings() and then just treat the first mapping in the list as the

Hi Quentin, Hi Amara, I was following your discussion on D75086 regarding declaring types as legal even if they are smaller than the actual register class (e.g. s16 and gpr32). We are working on a backend which only has 32 and 64-bit registers and we recently had a problem regarding exactly this where we had to declare G_UNMERGE_VALUES and G_MERGE_VALUES with a smaller type of <s32 as

> On May 5, 2020, at 2:45 PM, Ties Stuij <Ties.Stuij at arm.com> wrote: > > Quentin: Thanks for the info. I was under the impression that the LLVM community at large would prefer to extend the IR type to a bfloat MVT type. I've made a number of patches to implement this up to a point for AArch64. I can post those on Phab and start a thread to sample opinions. Sounds good to

Hi all, first of all thanks to Matt for hosting the round table yesterday and to everyone else for their time and the valuable discussions. As promised in the chat yesterday, here is the email regarding the legalizer / artifact combiner issue we talked about. I will send a separate email regarding the regbankselect discussion. In case someone on the list didn't attend the round table

> On May 1, 2020, at 10:28 AM, Arsenault, Matthew <Matthew.Arsenault at amd.com> wrote: > > [AMD Public Use] > > > It seems to me like you're looking for a workaround for the fact that nobody has put any serious optimization effort into RegBankSelect Practically speaking, we have a compile time budget, and spending that on reconstructing information which we

Hi Medhi, > On Dec 11, 2015, at 6:18 PM, Mehdi Amini <mehdi.amini at apple.com> wrote: > > Hi, > > Side note: shouldn’t RFCs rather go to llvm-dev? You’re right! I could have sworn I have sent it to llvm-dev! Moving it now. > >> On Dec 11, 2015, at 5:44 PM, Quentin Colombet via llvm-commits <llvm-commits at lists.llvm.org> wrote: >> >> Hi,

Hi, I’m looking at RegBankSelect’s partially implemented support for deciding to split a value between multiple registers and I’m wondering if it’s actually intended to solve the problem I’m trying to use it for. RegisterBankInfo.h has this example mapping table: /// E.g., /// Let say we have a 32-bit add and a <2 x 32-bit> vadd. We /// can expand the /// <2 x 32-bit> add into

Hi David, > On Nov 18, 2015, at 11:55 AM, David Chisnall <David.Chisnall at cl.cam.ac.uk> wrote: > > Hi Quentin, > > On 18 Nov 2015, at 19:26, Quentin Colombet via llvm-dev <llvm-dev at lists.llvm.org> wrote: >> >> In the section “Goals", I defined (repeated for people that saw the talk) the goals for the Global ISel design. >> - Do you see

Hi Quentin, I’ve started running an ABI test suite with global isel on AArch64, and while it hasn’t found any ABI issues it has hit an assertion in clang when using the __fp16 type. Here’s a reproducer: __fp16 pass_f16(__fp16 p) { return p; } $ /work/llvm/build/bin/clang --target=aarch64-arm-none-eabi -march=armv8-a -c test.c -O0 -mllvm -global-isel -mllvm -global-isel-abort=0

> On Feb 21, 2019, at 12:18 AM, Quentin Colombet via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Hi Matt, > >> On Feb 20, 2019, at 4:49 PM, Arsenault, Matthew via llvm-dev <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote: >> >> Hi, >> >> Some operations on AMDGPU require operands which must be in a register

Hi Dominik, Thanks for your reply. In my case, the Defs is the cause of the problem. Or rather, it is part of the problem, because when I remove it from the instruction TableGen gives me a different error message which concerns a part which is deeper into the pattern tree, so at least it is able to proceed beyond that part of the pattern. I have also stepped TableGen inside gdb and

Hi, Some operations on AMDGPU require operands which must be in a register bank that is impossible to copy from another. The operation needs to be rewritten in a complex way to avoid the illegal copy. Currently if I correctly report the required register banks in the operand mapping, RegBankSelect happily inserts the illegal copies, somehow concluding they are cheap (I would at least hope

Hi Daniel, Thanks for replying; I was hoping to get in touch with you on this issue. I had a look at how SelectionIDAG does it when generating the matcher table, and it does consider the implicit defs as additional output. Here is the match table generated for the pattern: /* 0*/ OPC_CheckOpcode, TARGET_VAL(ISD::SIGN_EXTEND), /* 3*/ OPC_MoveChild0, /* 4*/ OPC_CheckOpcode,

You can use htmlTreeParse and xpathApply from the XML library. something like: xpathApply( htmlTreeParse("http://blabla", useInt=T), "//td", function(x) xmlValue(x)) should do it. Gamma wrote: > > anyone care to explain how to read a html table, it's streaming data > (updated every second) and i am looking for a suitable function. > > The imported html