Re: [lmi] [lmi-commits] valyuta/005 4483b09 1/9: Avoid passing 'currency' by const reference

[Vadim Zeitlin]

On Wed, 20 Jan 2021 00:51:31 -0500 (EST) Greg Chicares 
<gchicares@sbcglobal.net> wrote:

GC> branch: valyuta/005
GC> commit 4483b09a9bf445c58b1be677221a72fbde4de13f
GC> Author: Gregory W. Chicares <gchicares@sbcglobal.net>
GC> Commit: Gregory W. Chicares <gchicares@sbcglobal.net>
GC> 
GC>     Avoid passing 'currency' by const reference
GC>     
GC>     See:
GC>       https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rf-in
GC>     sizeof(currency) equals sizeof(double), so pass by value.
GC>     
GC>     This change would appear to make both 32- and 64-bit msw builds slightly
GC>     slower, so is the guideline appropriate for currency operators?

 This is very, very astonishing. Are the benchmark results reproducible for
you?

 I'd expect gcc to optimize away the references anyhow with any -O options,
so I'm surprised that the results are not exactly the same, but I just
can't explain how could they differ in this direction. I may look at the
generated assembly, if you'd like, because this is just too strange.

 Regards,
VZ

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