2016 LLVM Developers’ Meeting: N. Lopes “Undefined Behavior: Long Live Poison!'

preview_player
Показать описание
—
Undefined Behavior: Long Live Poison! - N. Lopes, Microsoft Research

—
The current concept of poison in LLVM is known to be broken, leaving LLVM in a state where certain miscompilation bugs are hard or even impossible to fix. Moreover, the concepts of poison and undef values in LLVM are hard to reason about and are often misunderstood by developers.

However, we need concepts similar to poison and undef to enable certain important optimizations.

In this talk, we will present the motivation behind poison and undef and why they are broken. We'll also present a proposal to kill undef and extend poison, while retaining their performance benefits.

This talk is meant to increase awareness of the issues and motivations behind poison/undef and discuss how to fix it.

Joint work with: Sanjoy Das, Gil Hur, Yoonseung Kim, Juneyoung Lee, David Majnemer, John Regehr, and Youngju Song.
—
  1. LLVM
  2. 2016 LLVM Developers' Meeting
  3. LLVM
Рекомендации по теме
2016 LLVM Developers’ 0:42:29

2016 LLVM Developers’ Meeting: N. Lopes “Undefined Behavior: Long Live Poison!'

2016 LLVM Developers’ 0:05:17

2016 LLVM Developers’ Meeting: N.Singhal “Reducing the Computational Complexity of RegionInfo”

2016 LLVM Developers’ 0:04:42

2016 LLVM Developers’ Meeting: N. Wilson 'Toward Fixed-Point Optimization in LLVM'

2016 LLVM Developers’ 0:40:53

2016 LLVM Developers’ Meeting: A. Nemet “Compiler-assisted Performance Analysis'

2016 LLVM Developers’ 0:57:08

2016 LLVM Developers’ Meeting: M. Amini & T. Johnson “ThinLTO: Scalable and Incremental LTO”...

2016 LLVM Developers’ 0:39:52

2016 LLVM Developers’ Meeting: M. Zolotukhin “Loop Passes: Adding new features while reducing...”...

2016 LLVM Developers’ 0:37:49

2016 LLVM Developers’ Meeting: H. Finkel “Intrinsics, Metadata, and Attributes...”

2016 LLVM Developers’ 0:41:19

2016 LLVM Developers’ Meeting: Z. Ansari 'Causes of Performance Instability due to Code ...&apo...

2016 LLVM Developers’ 0:40:27

2016 LLVM Developers’ Meeting: A. Bougacha & Q. Colombet & T. Northover “Global Instr..&apos...

2015 LLVM Developers’ 0:43:13

2015 LLVM Developers’ Meeting: Jf Bastien & Dan Gohman “WebAssembly: Here Be Dragons'

2016 LLVM Developers’ 0:37:26

2016 LLVM Developers’ Meeting: R. Kleckner 'CodeView, the MS Debug Info Format in LLVM'

2016 LLVM Developers’ 0:05:27

2016 LLVM Developers’ Meeting: I. Biryukov “How compiler frontend is different from what IDE needs?”...

2016 LLVM Developers' 0:30:19

2016 LLVM Developers' Meeting: S. Cook 'Using LLVM to guarantee program integrity'

2016 LLVM Developers’ 0:38:48

2016 LLVM Developers’ Meeting: P. Padlewski “Devirtualization in LLVM”

2016 LLVM Developers’ 0:04:31

2016 LLVM Developers’ Meeting: G. Burgess “MemorySSA in Five Minutes”

2016 LLVM Developers’ 0:49:21

2016 LLVM Developers’ Meeting: L. Hames “ORC -- LLVM's Next Generation of JIT API”

2016 LLVM Developers’ 0:05:25

2016 LLVM Developers’ Meeting: P. Robinson “FileCheck Follies”

2016 LLVM Developers’ 0:04:13

2016 LLVM Developers’ Meeting: U. Bora “Polly as an analysis pass in LLVM”

2017 EuroLLVM Developers’ 0:34:40

2017 EuroLLVM Developers’ Meeting: N. Hickey & J. Kuderski “SPIR-V infrastructure ...”

2018 LLVM Developers’ 0:24:58

2018 LLVM Developers’ Meeting: J. Groff & D. Gregor “Efficiently Implementing Runtime Metadata.....

2016 LLVM Developers’ 0:40:33

2016 LLVM Developers’ Meeting: D. Dunbar “A New Architecture for Building Software”

2016 LLVM Developers’ 0:02:42

2016 LLVM Developers’ Meeting: S. Moll “RV: A Unified Region Vectorizer for LLVM”

2015 LLVM Developers’ 0:58:50

2015 LLVM Developers’ Meeting: S. Guelton & A. Guinet '...Simple out-of-tree LLVM Pass&apos...

2018 LLVM Developers’ 0:05:03

2018 LLVM Developers’ Meeting: N. Weber “Funner LLVM development”