[LLVMdev] Need a clue to improve the optimization of some C code

Philip Reames listmail at philipreames.com
Wed Mar 4 14:54:50 PST 2015

On 03/04/2015 03:51 AM, Nat! wrote:
> Updating my previous mail...
> Am 03.03.2015 um 20:20 schrieb Nat! <nat at mulle-kybernetik.com>:
>>> 2) Are you tracking ToT?  If you're not, you should be.
>> Currently the git repo doesn't build for me (libLLVMR600CodeGen fails). Admittedly my IR output is from an older version - 3.6.
> Ok, I got the trunk to build now. Luckily indeed the emitted assembler code has improved (a lot). Yet the produced code is still a bit larger than what it would be if written by hand. Since I try to optimize for size, my question how it would be smart to tackle this within LLVM remains.
File a bug report with a small IR reproducer of the problematic code 
sequence.  Ideally, send a patch to llvm-commits.

Also, make sure you're using -Oz if you care about size above all.
> Thanks for any feedback.
> Ciao
>     Nat!
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