To: J3 J3/16-281 From: R. Bader Subject: specification of SYNC MEMORY Date: 2016 October 07 References: 16-007r2 Discussion: ~~~~~~~~~~~ The specification of the ordering properties of SYNC MEMORY described in 11.6.5 SYNC MEMORY statement, para 2 appear to be in contradiction to the explanatory text for the atomic subroutines appearing in Appendix C.12.2.2, in particular [596:21-25]. This seems to be related to at least a subset of the hen-and-egg problems brought up by Nick Maclaren. Edits are provided below based on the conclusion that atomic references and definitions should be excepted from the general ordering properties. Suggested edits: ~~~~~~~~~~~~~~~~ [209:6] and [210:3]: replace "defined, referenced" by "nonatomically defined, nonatomically referenced", twice. [210:6+]: Add sentence "If P is the same image as Q, atomic definitions or references to X before the SYNC MEMORY precede atomic definitions or references to Y after the SYNC MEMORY statement." {this appears to be necessary to continue ensuring that such defs and refs are not moved across the SYNC MEMORY by the optimizer}.