Messages in this thread | | | Date | Mon, 18 Mar 2019 10:14:28 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] lib: Add shared copy of __lshrti3 from libgcc |
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On Fri, Mar 15, 2019 at 03:06:37PM -0700, Nick Desaulniers wrote: > On Fri, Mar 15, 2019 at 1:54 PM Matthias Kaehlcke <mka@chromium.org> wrote: > > > > The compiler may emit calls to __lshrti3 from the compiler runtime > > library, which results in undefined references: > > > > arch/x86/kvm/x86.o: In function `mul_u64_u64_shr': > > include/linux/math64.h:186: undefined reference to `__lshrti3' > > Looks like Clang will emit this at -Oz (but not -O2): > https://godbolt.org/z/w1_2YC
*OMG*, what is that compiler smoking and why do we want that?
It doesn't even do that for "-Os".
So where "-Os" is "Optimize for Sadness" this "-Oz" thing is like a downright depression. Please just take it out back. Don't enable crap like this.
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