This 1998 note by Dennis Ritchie from comp.lang.c (and also here ) is very current since the concept of noalias has definitely crept back into the standard. I have reproduced it verbatim, but lightly formatted for readability. For further reading
C89 Standard
A text version of a non-final draft is below. Here’s the pdf of the final version. (This foreword is not a part of American National Standard for Information Systems — Programming Language C, X3.???-1988.) American National Standard Programming Language C
Semiotics of functional programming
In contrast to the usual imperative languages (e.g., C, Fortran, and Ada), in which variables represent cells in memory that can be modified using the assignment operator = (or :=), functional languages view the use of the = operator as
undefined behavior and the purpose of C
The C programming language is designed to let programmers work at both low and high levels. In particular, for applications like operating system development, cryptography, numerical methods, and network processing, programmers can go back and forth between treating data as
Three modest proposals for the C standard WG14
Note: these were sent to WG14 as official proposals. See also a longer paper, something on alias and Torvalds remarks and Regehr’s paper. 6.12 Proposal to clarify undefined behavior range for implementations [N 2278] 6.13 Proposal to make aliasing consistent [N
Vector optimization with C aliasing
One of the common defenses of the abuse of “undefined behavior” by C compilers, and the stupid aliasing rules in the standard is that those things are necessary for optimizations, like using vector operations. Here’s an example of where gcc
Torvalds on aliasing
See also Dennis Ritchie on aliasing, PLOS article, pointer alias in C and remarks on the purpose of C. From: LKML From Linus Torvalds <> Date Tue, 5 Jun 2018 10:30:21 -0700 Subject Re: [GIT PULL] Device properties framework update for
Pointer alias analysis in C
Perhaps there is some reason to provide a mechanism for asserting, in a particular patch of code, that the compiler is free to make optimistic assumptions about the kinds of aliasing that can occur. I don’t know any acceptable way of
Depressing and faintly terrifying days for the C standard
C STANDARD UNDEFINED BEHAVIOR VERSUS WITTGENSTEIN 1. DEPRESSING AND FAINTLY TERRIFYING Chris Lattner, the architect of the Clang/LLVM C compiler explained the effects of the C standard’s “undefined behavior”(UB): UB is an inseperable part of C programming, […] this is
More UB madness from LLVM/Clang
Via @johnregehr this further tale of compiler “optimizations” that break correct C code without even a warning by deleting a necessary null pointer check. In this example, Bar contains a stack of Foos. Sometimes the Foo stack is empty, so