#12469: Memory fence on writes to MutVar/Array missing on ARM -------------------------------------+------------------------------------- Reporter: rrnewton | Owner: Type: bug | Status: patch Priority: normal | Milestone: 8.0.2 Component: Compiler | Version: 8.0.1 Resolution: | Keywords: memory model Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: 12537 Related Tickets: | Differential Rev(s): Phab:D2495 Wiki Page: | Phab:D2525 -------------------------------------+------------------------------------- Comment (by trommler): Replying to [comment:27 trommler]:
Replying to [comment:25 simonmar]:
If a `sync` fixes it then that would be a useful data point. If not, it means there are barriers missing elsewhere. I had not seen your comment on moving the write barrier.
If that was indeed the problem then there is a data dependency and we don't have to worry about a load-load barrier on PowerPC (and ARM).
I'll do a test build on a PowerPC 970MP and a POWER8. On POWER8 I still see a few panics in `mkFastStringWith` and on build service (qemu on POWER8 hardware) one panic with `ARR_WORDS object entered`. A couple of packages fail with segfaults in `Setup build`.
The PowerMac (PowerPC 970) build is still running. So far no panic but about the same number of packages as before fail in `Setup build`. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12469#comment:28 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler