llvm dev - Sep 2013 - [LLVMdev] How to prevent Dead-Code-Elimination pass removing pseudo-instructions ADJCALLSTACK(DOWN | UP)?

Hi, LLVMer.

I use pseudo-instructions ADJCALLSTACK(DOWN | UP) to adjust call stacks,
and it works well with "-O0" option. However, ADJCALLSTACK(DOWN | UP)
are
removed during codegen DCE pass under "-O2".

What have I ignored?

Thanks.

-- 
杨勇勇 (Yang Yong-Yong)
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20130904/3e51f557/attachment.html>

You should set them as using/defining your stack register with :

let Defs = [STACKREG], Uses = [STACKREG] in {
__ YOUR INSTRUCTION __
}

Marcello

On 04/09/13 07:56, 杨勇勇 wrote:
> I use pseudo-instructions ADJCALLSTACK(DOWN | UP) to adjust call 
> stacks, and it works well with "-O0" option. However, 
> ADJCALLSTACK(DOWN | UP) are removed during codegen DCE pass under
"-O2".

Thank you, Marcello. It works.


2013/9/4 Marcello Maggioni <marcello at codeplay.com>
> You should set them as using/defining your stack register with :
>
> let Defs = [STACKREG], Uses = [STACKREG] in {
> __ YOUR INSTRUCTION __
> }
>
> Marcello
>
>
> On 04/09/13 07:56, 杨勇勇 wrote:
>
>> I use pseudo-instructions ADJCALLSTACK(DOWN | UP) to adjust call
stacks,
>> and it works well with "-O0" option. However,
ADJCALLSTACK(DOWN | UP) are
>> removed during codegen DCE pass under "-O2".
>>
>
> ______________________________**_________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>
http://lists.cs.uiuc.edu/**mailman/listinfo/llvmdev<http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev>
>


-- 
杨勇勇 (Yang Yong-Yong)
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20130907/4ae7dec2/attachment.html>