similar to: Implement LLVM Intrinsics in C/LLVM IR

Have you looked at these? https://llvm.org/docs/LangRef.html https://llvm.org/docs/ExtendingLLVM.html On Tue, Mar 26, 2019 at 9:06 AM div code via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Of course, in this sense they are not platform-dependent. I just want to > write a semantics-correct version of such intrinsics and let my static > analyzer goes smoothly. > > On

Hello List, I am on the hook to instrument a piece of legacy LLVM IR code, and then we are planning to feed to the SeaHorn framework for some model checking tasks. After the instrumentation, I tried to use llc (version 3.9) to compile the IR code, and it works fine. However, when I try to use llc (version 3.8.1, the default llvm version of SeaHorn) to compile the IR code, it shows the following

Hello, I am on the hook to instrument a piece of legacy LLVM IR code, and then we are planning to feed to the SeaHorn framework for some model checking tasks. After the instrumentation, I tried to use llc (version 3.9) to compile the IR code, and it works fine. However, when I try to use llc (version 3.8.1, the default llvm version of SeaHorn) to compile the IR code, it shows the following

Hi, SystemZ supports @llvm.ctlz.i64() natively with a single instruction (FLOGR), and lesser bitwidth versions of the intrinsic are promoted to i64. For some reason, this leads to unfolded additions of constants as shown below: This function: define i16 @fun(i16 %arg) {   %1 = tail call i16 @llvm.ctlz.i16(i16 %arg, i1 false)   ret i16 %1 } ,gives this optimized DAG as input to instruction

Are you looking for something other than calling __builtin_clz from c++ or calling @llvm.ctlz.* instrinsic from IR? I don't think we have anything that will auto converting a loop to ctlz or anything like that. We only seem to have a detection for popcount loops. On Thu, Aug 15, 2013 at 9:01 PM, reed kotler <rkotler at mips.com> wrote: > Does anyone know some simple c/c++ code or

Hi all, Some non trivial legalization of operations which aren't supported by the backend would benefit from having the optimizer pass on them. I noticed some example trying to optimize various pieces of code over the past weeks. One offender is the cttz/ctlz intrinsic when defined on 0. On X86, BSR and NSF are undefined on 0, and only recent CPU have the LZCNT and TZCNT instructions that

Developers, As part of PR411, I have made several of the intrinsic functions non- overloaded. While the assembler and bytecode reader are backwards compatible, front-end writers should start using the non-overloaded versions of the intrinsics. The llvm-gcc has already been updated to generate the new intrinsic names. Other front-ends will start seeing warnings about the names of intrinsics that

I may be wrong here, but legalizing early seems like something that is more likely to prevent optimizations than it is to encourage them. But I guess I don't follow why things like TTI, TII and TLI queries don't suffice for this. CodeGenPrepare will break this sequence up. I would imagine that if the target returns false for isCheapToSpeculateCtlz() and false for canInsertSelect(), the

Does anyone know some simple c/c++ code or .ll code which will cause this ctlz pattern to be emitted? Tia. Reed

Hi Eli, Thanks for pointing to the CTLZ_ZERO_UNDEF “LibCall” implementation. I have not it in the version that I am currently using, so it’s nice to know that it’s implemented now. Incidentally, the CTLZ… implementation is IDENTICAL to what I am proposing for the Shifts. This is not just adding support for “out-of-tree-targets”, but giving consistency to the fact that we have perfectly defined

> On 2 Jul 2018, at 15:13, Matthias Braun via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > I had similar gripes with unit testing machine function stuff. I personally would have preferred to create more tests based on a tool like llc rather than pushing more on the unit test side. Anyway I tried to push https://reviews.llvm.org/D48850 <https://reviews.llvm.org/D48850> in

On 15 Jan 2010, at 18:03, Chris Lattner wrote: > On Jan 14, 2010, at 10:13 PM, David Conrad wrote: > >> Other targets that I know of that could potentially benefit from >> this optimization being global (that have a clz and bitreverse >> instruction but not ctz) are AVR32 and C64x, neither of which llvm >> has backends for yet. > > When/if another

LLVM appears to support Library functions for ISD::SRA ,ISD::SHL, and ISD::SRL, as they are properly defined in RuntimeLibCalls.def. The library functions defined in RuntimeLibCalls.def (among others) are these: HANDLE_LIBCALL(SRA_I16, "__ashrhi3") HANDLE_LIBCALL(SRA_I32, "__ashrsi3") HANDLE_LIBCALL(SRA_I64, "__ashrdi3") However, setting

Hi Eli, First of all, please I would appreciate that you try to not confuse my limited use of English with stupidity or lack or criteria in other subjects. I’m not English native, so please keep that in mind. You have been significantly helpful in the recent past so please keep on. Interestingly, you made a mention of a related but not identical issue. It is true that most (or all) processors

Hi. My name is Gil Dogon and I am working in MobileEye using LLVM in order to generate code for a proprietary processor. Our processor architecture is very similar to MIPS, so I started to work using the "experimental" MIPS back end. Anyway, my question is rather simple but somehow I did not find a quick answer to it in the documentation. What I want to know, is how can the

On Jan 15, 2010, at 11:37 AM, Richard Osborne wrote: > > On 15 Jan 2010, at 18:03, Chris Lattner wrote: > >> On Jan 14, 2010, at 10:13 PM, David Conrad wrote: >> >>> Other targets that I know of that could potentially benefit from >>> this optimization being global (that have a clz and bitreverse >>> instruction but not ctz) are AVR32 and C64x,

On Jan 15, 2010, at 2:52 PM, Jim Grosbach wrote: > > On Jan 15, 2010, at 11:37 AM, Richard Osborne wrote: > >> >> On 15 Jan 2010, at 18:03, Chris Lattner wrote: >> >>> On Jan 14, 2010, at 10:13 PM, David Conrad wrote: >>> >>>> Other targets that I know of that could potentially benefit from >>>> this optimization being

On 2018-05-16 00:34, Sanjay Patel via llvm-dev wrote: > Vectorization goes overboard because the throughput cost model used by > the > vectorizers doesn't match the 6 IR instructions that correspond to 1 > x86 > rotate instruction. Instead, we have: > > [...] > > The broken cost model also affects unrolling and inlining. Size costs > are > overestimated

I've been playing around with LLVM to write a backend for a rather "simple" (co-)processor. Assume that only three arithmetic instructions exist: ADD mod N, SUB mod N and MUL mod N. The modulus N is programmable and stored in a register. No ordinary arithmetic instructions are available. The word size is 256-bit. In other words, the following function, b + c mod N, corresponds to

Hi, I have a small JIT project based on MCJIT. The generated LLVM IR code uses the i256 type. Also, the jitted code has to call back the host application from time to time. E.g. it calls a function i256 @callback(i256). 1. Can the callback function be implemented on the host application side (C/C++) to match the ABI used for the call by MCJIT? Or maybe the i256 has be to be casted to