Write a Blog >>
SPLASH 2017
Sun 22 - Fri 27 October 2017 Vancouver, Canada
Thu 26 Oct 2017 10:52 - 11:15 at Regency C - Optimizing Compilation and Verification Chair(s): Gregor Richards

Series of traversals of tree structures arise in numerous contexts: abstract syntax tree traversals in compiler passes, rendering traversals of the DOM in web browsers, kd-tree traversals in computational simulation codes. In each of these settings, a tree is traversed multiple times to compute various values and modify various portions of the tree. While it is relatively easy to write these traversals as separate small updates to the tree, for efficiency reasons, traversals are often manually fused to reduce the number of times that each portion of the tree is traversed: by performing multiple operations on the tree simultaneously, each node of the tree can be visited fewer times, increasing opportunities for optimization and decreasing cache pressure and other overheads. This fusion process is often done manually, requiring careful understanding of how each of traversals of the tree interact. This paper presents an automatic approach to traversal fusion: tree traversals can be written independently, and then our framework analyzes the dependences between the traversals to determine how they can be fused to reduce the number of visits to each node in the tree. A critical aspect of our framework is that it exploits two opportunities to increase the amount of fusion: i) it automatically integrates code motion, and ii) it supports partial fusion, where portions of one traversal can be fused with another, allowing for a reduction in node visits without requiring that two traversals be fully fused. We implement our framework in Clang, and show across several case studies that we can successfully fuse complex tree traversals, reducing the overall number of traversals and substantially improving locality and performance.

Thu 26 Oct

Displayed time zone: Tijuana, Baja California change

10:30 - 12:00
Optimizing Compilation and VerificationOOPSLA at Regency C
Chair(s): Gregor Richards University of Waterloo
10:30
22m
Talk
The Tensor Algebra Compiler
OOPSLA
Fredrik Kjolstad MIT CSAIL, Shoaib Kamil Adobe, Stephen Chou MIT CSAIL, David Lugato CEA, France, Saman Amarasinghe MIT
DOI
10:52
22m
Talk
TreeFuser: A Framework for Analyzing and Fusing General Recursive Tree Traversals
OOPSLA
Laith Sakka Purdue University, Kirshanthan Sundararajah Purdue University, Milind Kulkarni Purdue University
DOI
11:15
22m
Talk
Verifying Spatial Properties of Array Computations
OOPSLA
Dominic Orchard University of Kent, UK, Mistral Contrastin , Matthew Danish University of Cambridge, UK, Andrew Rice University of Cambridge, UK
DOI
11:37
22m
Talk
GLORE: Generalized Loop Redundancy Elimination upon LER-Notation
OOPSLA
Yufei Ding North Carolina State University, Xipeng Shen North Carolina State University
DOI