pgsql-server: Adjust TAS assembly as per recent discussions: use - Mailing list pgsql-committers

Log Message:
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Adjust TAS assembly as per recent discussions: use "+m"(*lock) everywhere
to reference the spinlock variable, and specify "memory" as a clobber
operand to be sure gcc does not try to keep shared-memory values in
registers across a spinlock acquisition.  Also tighten the S/390 asm
sequence, which was apparently written with only minimal study of the
gcc asm documentation.  I have personally tested i386, ia64, ppc, hppa,
and s390 variants --- there is some small chance that I broke the others,
but I doubt it.

Modified Files:
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    pgsql-server/src/include/storage:
        s_lock.h (r1.125 -> r1.126)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/include/storage/s_lock.h.diff?r1=1.125&r2=1.126)