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Re: trans-mem: virtual ops for gimple_transaction
- From: Torvald Riegel <triegel at redhat dot com>
- To: Richard Henderson <rth at redhat dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, rguenther at suse dot de, Diego Novillo <dnovillo at google dot com>, Aldy Hernandez <aldyh at redhat dot com>
- Date: Fri, 10 Feb 2012 01:25:28 +0100
- Subject: Re: trans-mem: virtual ops for gimple_transaction
- References: <bug-51752-119-dJucciRs1z@http.gcc.gnu.org/bugzilla/> <4F345153.8090602@redhat.com>
On Thu, 2012-02-09 at 15:05 -0800, Richard Henderson wrote:
> + /* The beginning of a transaction is a memory barrier.
> */
> + /* ??? If we were really cool, we'd only be a barrier
> + for the memories touched within the transaction. */
Why? I'm not quite sure what kind of memory barrier you mean here, but
a transaction can synchronize with other transactions and thus should be
a barrier for all memory accesses, or not? We could move safe code into
it, but not out of it or across it. We could perhaps move
transaction_pure code across it, or out of it, IIRC.
Torvald