All, The often misunderstood GetElementPtr (GEP) instruction now has its own FAQ document. For all of you that have struggled with understanding how this instruction works, hopefully this document will make it clear and help you with your use of LLVM. Many thanks to Chris Lattner for setting me straight on how this instruction works and reviewing the document. Document Link : http://llvm.org/docs/GetElementPtr.html Best Regards, Reid.
hi Reid,
thanks for the documentation for this. Me too struggled at first with
this concept.
Regarding the page fragment references:
<a href="firstptr">What is the first index of the GEP
instruction?</a>
</li>
<li><a href="extra_index">Why is the extra 0 index
required?</a></li>
<li><a href="deref">What is dereferenced by
GEP?</a></li>
<li><a href="lead0">Why don't GEP x,0,0,1 and GEP
x,1 alias? </a></li>
<li><a href="trail0">Why do GEP x,1,0,0 and GEP x,1
alias? </a></li>
I think you should put a # in fron of the href values, otherwise my
preferred browser (firefox) thinks it is a website and not a document
fragment.
-- Jakob
Reid Spencer wrote:> All,
>
> The often misunderstood GetElementPtr (GEP) instruction now has its own
> FAQ document. For all of you that have struggled with understanding how
> this instruction works, hopefully this document will make it clear and
> help you with your use of LLVM. Many thanks to Chris Lattner for setting
> me straight on how this instruction works and reviewing the document.
>
> Document Link : http://llvm.org/docs/GetElementPtr.html
>
> Best Regards,
>
> Reid.
Hello, Reading through this, I found a typo... In the paragraph after the 3rd code snippet in the 1st question's section: "The second operand will be the field offset" seems like it should be the third operand? The second is the pointer offset... HTH! =] -Chandler Carruth On 8/15/06, Reid Spencer <rspencer at reidspencer.com> wrote:> > All, > > The often misunderstood GetElementPtr (GEP) instruction now has its own > FAQ document. For all of you that have struggled with understanding how > this instruction works, hopefully this document will make it clear and > help you with your use of LLVM. Many thanks to Chris Lattner for setting > me straight on how this instruction works and reviewing the document. > > Document Link : http://llvm.org/docs/GetElementPtr.html > > Best Regards, > > Reid. > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20060816/837745b1/attachment.html>
Yup. Fixed. Thanks. Reid. On Wed, 2006-08-16 at 00:39 -0400, Chandler Carruth wrote:> Hello, > > Reading through this, I found a typo... > > In the paragraph after the 3rd code snippet in the 1st question's > section: > "The second operand will be the field offset" seems like it should be > the third operand? The second is the pointer offset... > > HTH! =] > -Chandler Carruth > > > > On 8/15/06, Reid Spencer <rspencer at reidspencer.com> wrote: > All, > > The often misunderstood GetElementPtr (GEP) instruction now > has its own > FAQ document. For all of you that have struggled with > understanding how > this instruction works, hopefully this document will make it > clear and > help you with your use of LLVM. Many thanks to Chris Lattner > for setting > me straight on how this instruction works and reviewing the > document. > > Document Link : http://llvm.org/docs/GetElementPtr.html > > Best Regards, > > Reid. > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev