[LLVMdev] understanding the opt tool

Samuel Crow samuraileumas at yahoo.com
Sat Apr 17 10:02:23 PDT 2010

Hello Kalyan,

There is one more thing you should know:  Clang has maximum optimization turned on by default.  You need to specify -O0 to turn it off if you want to see what opt does without clang running all of the optimizations first.


----- Original Message ----
> From: Duncan Sands <baldrick at free.fr>
> To: llvmdev at cs.uiuc.edu
> Sent: Sat, April 17, 2010 2:00:00 AM
> Subject: Re: [LLVMdev] understanding the opt tool
> Hi Kalyan,

> opt -strip-dead-prototypes -f <filename.bc> 
> filename2.bc

you have to specify the list of passes to run.  
> -strip-dead-prototypes
only removes unused declarations.  If there are 
> none, it will do nothing.
   opt -std-compile-opts -f 
> <filename.bc> 
> filename2.bc


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