[LLVMdev] precondition suggestion to LLVM

Dmitry N. Mikushin maemarcus at gmail.com
Mon Oct 22 20:06:06 PDT 2012

Hi Niko,

Do you mean branch prediction, i.e. __builtin_expect [1]? Many
compilers support it, I think clang (LLVM's C/C++ frontend) is among

- D.

[1] http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html

2012/10/23 Niko Zarzani <koni10 at hotmail.it>:
> Hi all,
> Is there any way to tell LLVM some additional information about the
> variables in the code in order to make better optimization?
> For example, if my function has a certain precondition (such as x>0) then it
> will be possible to better optimize the code given that information (which
> the compiler does not know).
> I am new in this field and I don't know if there are ways to tell the
> compiler preconditions (such as by using some preprocessing directives).
> Thank you in advance,
> Niko Zarzani
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