[llvm-bugs] [Bug 27168] New: atomicrmw and cmpxchg should support align attribute

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=27168

            Bug ID: 27168
           Summary: atomicrmw and cmpxchg should support align attribute
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: Core LLVM classes
          Assignee: unassignedbugs at nondot.org
          Reporter: jyknight at google.com
                CC: llvm-bugs at lists.llvm.org
    Classification: Unclassified

Currently, atomic load/store instructions support an align attribute, and
require that it be specified (you can't use the default ABI alignment like with
non-atomic load/store). On the other hand, cmpxchg and atomicrmw don't support
an align attribute at all. They just assume the pointer has natural alignment.

I'd like to be able to specify alignment for atomicrmw and cmpxchg, and,
further, I think it should be required just like atomic load/store. This will
make the atomic ops be consistent, but more importantly, will let clang lower
even unaligned atomics access to llvm IR (which is part of my long-term plan
for atomics cleanup).

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20160331/39598014/attachment.html>