similar to: [LLVMdev] A simple question regarding LLVM intrinsics.

Personally I would just modify the frontend - it's not that hard once you know where to look . In this case all you need to do is add the declaration of your builtin to the TARGET_INIT_BUILTINS target hook (see the gcc internals manual) defined in the gcc/config directory corresponding to your target. If the name the the declaration matches the name used with GCCBuiltin in the intrinsics

OK , grepping the whole source tree for 'ctlz' I found the answer to my question in: test/FrontendC/2006-01-16-BitCountIntrinsicsUnsigned.c and that is to use gnu frontend style __builtin_clz() for this one. This test/FrontendC directory has a plethora of other usefull examples so I guess It will be sufficient for me. However I still think that some documentation of the frontend

As mentioned in an earlier mail, I am working on an LLVM backend for a custom processor based on MIPS. My problem is how to extend LLVM to support some esoteric/non-standard feature of the underlying hardware. I saw in the "Extending LLVM" document, that the easiest / most common way to do this was using an intrinsic function, and examples of the technique abound (all SSE for

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

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

Hello, I am basically working on a static analysis project on LLVM IR, and the problem is that I will need to simulate the execution of a few LLVM Intrinsic, such as llvm.bswap.i160, and llvm.ctlz.i256. I am wondering if there has been some already implemented sample code, regarding these intrinsics? Either C or LLVM IR. Thanks a lot! Best, -------------- next part -------------- An HTML

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

Chris Lattner wrote: > As others have mentioned, hacking the front-end isn't that hard. In > any case though, please be aware that a precompiled binary for a non- > MIPS target won't produce correct code if you are (for example) using > an x86 front-end and forcing llc to generate mips code with llc - > march=mips. The front-end does type layout and knows very ABI

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

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

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

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

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

Hello. I have a problem which is quite basic for array optimization, amd I wonder whether I am missing something, but I could not find the LLVM pass that does it. Consider the following code snippet: int test() { int mat[7][7][7]; int i,j,k,sum=0; for(i=0;i<7;i++){ for(j=0;j<7;j++){ for(k=0;k<7;k++){ sum+=mat[i][j][k]^mat[i][j][k^1]; } } } return

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

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