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0 pointszeusk3y ago0 comments

memcpy is more like copying a single line, to copy a rectangle you need to call it in a loop or use specialized blit hw/sw.

How is MLIR different from LLVM IR?

And tile/block processing is not that novel for generic compute, graphics use it for other reasons - mostly how the pixel data is in memory and how the pipeline scales with tile size.

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joaonmatos3y ago

LLVM is geared towards providing a single toolchain for frontends to target, but is essentially made to target von Neumann/serial-ish/homogenous machines. You can get an overview of its philosophy in Lattner’s original 2004 paper [1]. MLIR (Lattner 2021 [2]) aims to generalize the compiler toolchain to support different compute paradigms and heterogeneous targets (polyhedral compilation/parallel kernels/afine loops) and so on, by defining a declarative framework of IR _dialects_ and transforms between them. I’m writing my MSc thesis on using C/C++ as the IR, assuming it has enough compiler support for different targets to provide a suitable platform for optimisation transforms using a source-to-source compiler, but MLIR seems like a better first-principles approach, maybe suffering from the impracticality of using it _right now_.

[1] "LLVM: A Compilation Framework for Lifelong Program Analysis & Transformation", Lattner and Adve. https://llvm.org/pubs/2004-01-30-CGO-LLVM.pdf

[2] “MLIR: Scaling Compiler Infrastructure for Domain Specific Computation”, Lattner et al. https://ieeexplore.ieee.org/document/9370308

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