[LLVMdev] How to use LLVM optimizations with clang

[Chad Rosier]

On Jun 7, 2012, at 10:59 AM, Abdul Wahid Memon wrote:

> Hello everyone
> 
> I am trying to use some LLVM optimizations like -die or -adce. Is it
> possible to use them along clang?
> 
> Or is there a way where these optimization can be passed on to "opt"
> tool through clang, if opt is being used by clang behind the scenes?
> 

No, opt only works on llvm IR/bitcode.  You can generate it like this:
clang -c foo.c -emit-llvm -o foo.bc
or
clang -S foo.c -emit-llvm -o foo.ll

Then you can run the optimization(s):
opt -adce foo.bc -o foo-adce.bc

Then you can compile using clang
clang -c foo-adce.bc -o foo-adce.o

 Chad

> Thanks alot
> 
> Regards
> 
> Shahzad
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