llvm dev - Apr 2015 - [LLVMdev] How to see what's going on behind llc through clang/clang++

Hi,

Is there a way to see what the default argument llc takes from
clang/clang++ ? I'm debugging my backend with a very simple c++ program.
Running through

*clang++ -target myTarget -S simple.cpp -o simple.s * (bug does no show up)

gives me different results from

*clang++ -target myTarget -S -emit-llvm -o simple.cpp -o simple.ll*
*llc simple.ll -o simple.s *(bug shows up)

Just trying to understand what's the difference here

Thanks,
Patrick
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20150407/ed40cbce/attachment.html>

Default optimisation levels are different for one thing. Try running
`llc -O0 ...` and see if that makes a difference.

There is an option to print the LLVM-IR code before/after each pass:
-print-after-all and -print-before-all

--
Mats


On 7 April 2015 at 15:11, Ziqiang Patrick Huang
<ziqiang.huang1001 at gmail.com> wrote:
> Hi,
>
> Is there a way to see what the default argument llc takes from
clang/clang++
> ? I'm debugging my backend with a very simple c++ program. Running
through
>
> clang++ -target myTarget -S simple.cpp -o simple.s  (bug does no show up)
>
> gives me different results from
>
> clang++ -target myTarget -S -emit-llvm -o simple.cpp -o simple.ll
> llc simple.ll -o simple.s (bug shows up)
>
> Just trying to understand what's the difference here
>
> Thanks,
> Patrick
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>

Thanks, Mats

Is there a way to pass llc options through clang/clang++ ?

Patrick

2015-04-07 11:20 GMT-04:00 mats petersson <mats at planetcatfish.com>:
> Default optimisation levels are different for one thing. Try running
> `llc -O0 ...` and see if that makes a difference.
>
> There is an option to print the LLVM-IR code before/after each pass:
> -print-after-all and -print-before-all
>
> --
> Mats
>
>
> On 7 April 2015 at 15:11, Ziqiang Patrick Huang
> <ziqiang.huang1001 at gmail.com> wrote:
> > Hi,
> >
> > Is there a way to see what the default argument llc takes from
> clang/clang++
> > ? I'm debugging my backend with a very simple c++ program. Running
> through
> >
> > clang++ -target myTarget -S simple.cpp -o simple.s  (bug does no show
up)
> >
> > gives me different results from
> >
> > clang++ -target myTarget -S -emit-llvm -o simple.cpp -o simple.ll
> > llc simple.ll -o simple.s (bug shows up)
> >
> > Just trying to understand what's the difference here
> >
> > Thanks,
> > Patrick
> >
> >
> >
> > _______________________________________________
> > LLVM Developers mailing list
> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >
>


-- 
*Ziqiang Huang*
*Electrical and Computer Engineering*
*Hudson 213c, Duke University*
*Tel: 919-491-3677*
*Email: ziqiang.huang at duke.edu <ziqiang.huang at duke.edu>*
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20150408/0b963126/attachment.html>