[LLVMdev] new LLVM IR features
gohman at apple.com
Wed Jul 29 11:25:21 PDT 2009
On Jul 29, 2009, at 9:41 AM, David Greene wrote:
> On Wednesday 29 July 2009 11:25, Dan Gohman wrote:
>> Getelementptr now has an optional flag: inbounds. WIth this flag,
>> if the result of a getelementptr is not in bounds of an allocated
>> the result value is undefined. Note the the new getelementptr rule
>> applies regardless of whether the keyword is present.
> How do the semantics of "inbounds" differ from the new GEP rules?
The new GEP rule says that you can't dereference a pointer within an
object if it was computed from a GEP based on a different object.
The optional inbounds flag further constrains a GEP by saying that
the integer arithmetic implied by a GEP won't overflow.
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