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[Bug tree-optimization/17884] [4.0 Regression] asm 'volatile' is not honored as documented
- From: "dalej at apple dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 8 Oct 2004 21:04:17 -0000
- Subject: [Bug tree-optimization/17884] [4.0 Regression] asm 'volatile' is not honored as documented
- References: <20041007193056.17884.fjahanian@apple.com>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From dalej at apple dot com 2004-10-08 21:04 -------
The question was discussed extensively in 2001. The phrase
"In addition, GCC will not reschedule
instructions across a volatile asm instruction."
was added here, by Mark Mitchell based on an earlier comment by rth.
http://gcc.gnu.org/ml/gcc-patches/2001-04/msg01477.html
If you read the whole thread, rth is quite firm that 'asm volatile' is
a scheduling barrier.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17884