amd64/atomic: silence warnings

[ggouaillardet]

Solaris Studio compilers issue (tons of) warnings because one arguments of several asm volatile section is not needed

[ggouaillardet]

without this patch, Solaris Studio compiler issues tons of warnings

"../../../../src/ompi-master/opal/include/opal/sys/amd64/atomic.h", line 163: warning: parameter in inline asm statement unused: %3
"../../../../src/ompi-master/opal/include/opal/sys/amd64/atomic.h", line 209: warning: parameter in inline asm statement unused: %2
"../../../../src/ompi-master/opal/include/opal/sys/amd64/atomic.h", line 230: warning: parameter in inline asm statement unused: %2
"../../../../src/ompi-master/opal/include/opal/sys/amd64/atomic.h", line 251: warning: parameter in inline asm statement unused: %2
"../../../../src/ompi-master/opal/include/opal/sys/amd64/atomic.h", line 272: warning: parameter in inline asm statement unused: %2

[hjelmn]

I think you will need to additionally change "=m" to "+m" to indicate that the pointer is both read and written by the atomic. I think that must have been the intent of the "m" (*v) lines.

[hjelmn]

From the inline asm manual:

Output constraints must begin with either ‘=’ (a variable overwriting an existing value) or ‘+’ (when reading and writing). When using ‘=’, do not assume the location contains the existing value on entry to the asm, except when the operand is tied to an input; see Input Operands.

[ggouaillardet]

got it, thanks !
I will update the PR tomorrow

[ggouaillardet]

@hjelmn I updated the PR, can you please review it again ?

[ibm-ompi]

Test passed.

[hjelmn]

Looks good to me. Retesting then merging.

:bot:retest: