https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85683

Alexander Monakov <amonakov at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2018-05-07
                 CC|                            |amonakov at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
Smaller testcase:

void f(void);

void g(int *p)
{
    if (!--*p)
        f();
}

On gcc-7.3 this is optimized by the peephole2 pass so it doesn't really help
with register pressure (combine pass seems more suitable for that); don't know
why the peephole doesn't trigger on gcc-8.

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