[LLVMbugs] [Bug 22927] New: CFL-AA is too conservative with inttoptr/ptrtoint instructions.

[bugzilla-daemon at llvm.org]

https://llvm.org/bugs/show_bug.cgi?id=22927

            Bug ID: 22927
           Summary: CFL-AA is too conservative with inttoptr/ptrtoint
                    instructions.
           Product: libraries
           Version: trunk
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: Global Analyses
          Assignee: unassignedbugs at nondot.org
          Reporter: george.burgess.iv at gmail.com
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified

CFLAA will answer more conservatively than it needs to given the following
code:

%A = ptrtoint %Ptr
%B = inttoptr %A
; A is otherwise unused (or used only in other inttoptr instructions)

At the moment, the sets attached to %Ptr and %B will be marked as with
AttrUnknown, but if we can prove that %A is used only in inttoptr instructions,
then we can avoid the "unknown" attribute and simply unify the sets for %A, %B,
etc.

Thanks to ol.sall at gmail.com for bringing this up.

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