similar to: Question about physical registers in ISel

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

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

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

Hi Hal, Thanks for the guidance. I hope you don’t mind that I’m adding LLVMDev to this e-mail thread, as it seems as though it may be of general interest. I agree that duplicating the FP opcodes should be our goal. I just wasn’t sure that was entirely possible. I’ll try adding implicit defs in the way you’ve suggested, but I’m concerned that there may be code that relies on the TII for that

Hi all, At Sony we developed an LLVM based performance analysis tool named llvm-mca. We currently use it internally to statically measure the performance of code, and to help triage potential problems with target scheduling models. We decided to post this RFC because we are interested in the feedback from the community, and we also believe that other people might be interested in a tool like

On Nov 9, 2011, at 2:12 PM, Chris Lattner wrote: > On Nov 9, 2011, at 1:08 PM, Jim Grosbach wrote: >>> On Nov 9, 2011, at 10:49 AM, Jim Grosbach wrote: >>>>> >>>>> It's not good, but people do it. Also constructing enums via & and | etc. It'd be nice to be able to get the name of whatever it is that the code generator actually produced :)

Hi Jochen, > My llvm version is 3.0 release. > I have a module generated by clang. When I optimize it, I first add an > inlining pass (llvm::createFunctionInliningPass), then these passes: > - own FunctionPass > - llvm::createPromoteMemoryToRegisterPass > - llvm::createInstructionCombiningPass > - llvm::createDeadInstEliminationPass > - llvm::createDeadStoreEliminationPass

Are you talking about the type checking done in CodeGenDAGPatterns.cpp? Is it easy to post an example? At 11/18/2020 01:55 PM, Thomas Lively wrote: >Hi Paul, > >I think this would be time well spent. At least in the WebAssembly backend, the vast majority of our ISel work is still done with DAG ISel. I know this is different from the performance work you have in mind, but one of my

Hi! My llvm version is 3.0 release. I have a module generated by clang. When I optimize it, I first add an inlining pass (llvm::createFunctionInliningPass), then these passes: - own FunctionPass - llvm::createPromoteMemoryToRegisterPass - llvm::createInstructionCombiningPass - llvm::createDeadInstEliminationPass - llvm::createDeadStoreEliminationPass - new llvm::DominatorTree() - new

Hi all, i'm working atm on a backend for a processor architecture that is capable of storing the carry flag of ADDC in an 1-bit register class. So I tried to lower the ADDC instruction to generate two register values as result. On the tablegen description of the instruction i came across the tablegen restriction that only one output result of one instruction is possible:

> On Mar 1, 2018, at 9:22 AM, Andrea Di Biagio <andrea.dibiagio at gmail.com> wrote: > > Hi all, > > At Sony we developed an LLVM based performance analysis tool named llvm-mca. We > currently use it internally to statically measure the performance of code, and > to help triage potential problems with target scheduling models. We decided to > post this RFC because

Hi Susan, > 1. I tried running the PBQP allocator (as a dynamic pass), but that didn't > work.... Can you tell from this what I'm doing wrong? > The PBQP allocator is built into the LLVM CodeGen library, so the "-regalloc=pbqp" option is already available in llc. If you've built a copy of the PBQP allocator in a separate library it will try to re-register

Hi, During instruction selection, I have the following code for certain LOAD instructions: const LoadSDNode *LD = cast<LoadSDNode>(N); SDNode* LDW = CurDAG->getMachineNode(AVR::LDWRdPtr, SDLoc(N), VT, PtrVT, MVT::Other, LD->getBasePtr(), LD->getChain()); // Honestly, I have no idea what this does, but other memory // accessing instructions

Hello LLVM, I'd like to check TSFlags in my AsmBackend code. However AsmBackend objects don't have a reference to MCInstrInfo, which is the only way I've seen to reach TSFlags. A quickie grep shows that none of the existing targets check TSFlags in their AsmBackends. Is there any reason I shouldn't check TSFlags in AsmBackend? If not, what's the best way to go about it?

Hello. Excuse me. Why CMakeLists.txt from llvm-3.9.1.src does not contain WebAssembly target? So, it is like set(LLVM_ALL_TARGETS AArch64 AMDGPU ARM BPF Hexagon Mips MSP430 NVPTX PowerPC Sparc SystemZ X86 XCore ) but not like set(LLVM_ALL_TARGETS AArch64 AMDGPU ARM BPF Hexagon Mips MSP430 NVPTX PowerPC Sparc SystemZ Webassembly X86

Okay, so where should I send questions for WebAssembly? Is it this mailing list or a different one? I want to ask about how to compile WebAssembly modules with Clang directly, without Emscripten, for situations like what I have currently where I have a problem with generating WebAssembly and/or JavaScript glue code (I have a problem with the gen_struct_info stuff; I asked on the Emscripten

Hi llvm-dev, I recently updated the WebAssembly TargetTransformInfo to allow functions with different target feature sets to be inlined into each other, but I ran into an issue I want to get the community's opinion on. Since WebAssembly modules have to be validated before they are run, it only makes sense to talk about WebAssembly features at module granularity rather than function

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

Hello all, WebAssembly [0] its a new virtual ISA being designed to efficiently run compiled code in web browsers and other things, starting with C/C++, and eventually many other languages [1]. WebAssembly distinguishes itself from other virtual ISAs with optimizations to reduce download size and decode time, strong portability and predictability invariants (for example, the base has no undefined

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