On Wed, May 17, 2017 at 11:45:50AM +0200, Christophe de Dinechin wrote: > > I'm really sure no architecture on hearth can do check and print in > > a single machine instruction. > > This is not what I said. I said that the cost in the likely case was one > extra instruction. > > > Actually I don't know any architecture > > where a single check like this can be done in a single instruction. > > Reduced source code: https://pastebin.com/ibZEVThA. > > Machine code for x86 with clang: https://pastebin.com/Vmtwpkhf > > The test follows the call to malloc. It’s a single “testb” instruction > followed by a never-taken conditional jump to cold-code.
NB: feel free to annotate such tests with G_LIKELY/G_UNLIKELY Christophe
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