[LLVMdev] Reproducing clang -O3 with opt

Tobias Grosser tobias at grosser.es
Wed Dec 3 00:37:54 PST 2014

On 03.12.2014 09:19, Adam Nemet wrote:
> This is probably a trivial question but the way I used to do this turns out to be flawed.
> I used run clang with -O0 -emit-llvm and then use the resulting IR with opt -O3.  The problem is that clang at -O0 does not generate TBAA metadata so the passes run by opt behave differently.
> What’s the recommended way of doing this?

I normally run 'clang -O3 -mllvm -disable-llvm-optzns' followed by 'opt 


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