| From: | Thomas Lockhart <lockhart(at)fourpalms(dot)org> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Intermediate report for AIX 5L port |
| Date: | 2001-12-11 00:53:40 |
| Message-ID: | 3C155914.BD00207C@fourpalms.org |
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| Lists: | pgsql-hackers |
...
> Declaring the lock pointer "volatile" seems to prevent this misbehavior.
Great. That is what it is anyway, right?
> Personally I'd call this a compiler bug; isn't it supposed to consider
> semicolons as sequence points? I never heard that rearranging the order
> of stores into memory was considered a kosher optimization of C code.
Sure it is. Presumably "-O0" or equivalent would have kept this from
happening, but seemingly unrelated stores into non-overlapping memory
are always fair game at even modest levels of optimization. The "x = 0"
is cheaper than the other operations, though it may be reordered for
internal RISC-y reasons rather than "cheapest first" considerations.
- Thomas
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