Re: [gpsd-dev] register keyword?

[Gary E. Miller]

Yo Kurt!

On Mon, 22 Jan 2018 15:04:13 -0800
Kurt Schwehr <address@hidden> wrote:

> The general compiler folks consensus is that the optimizers generally
> just ignore register and it's being removed from C++17.  Linking
> against C++17 code is my main reason for this.

Uh, this is C code, not C++ code.  What are you linking it to?

> But that's why we have https://godbolt.org/ to easily try it out.

Well, that is fun.  It also shows the register keyword really helps.  Ar
least when I select a C compiler.

> Looking at gcc x86-64 7.2, the assembly without register is shorter.

I see your point in C++ mode, but not in C mode.  In C mode the
register keyword is a real win.

>    #pragma GCC optimize("O3")
> 
> The assembly with and without registers is exactly the same.

Except gpsd does not use -O3.  I see similar on -o2, which gpsd does
use, except that optimization will not work for a linked in function.

RGDS
GARY
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