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Re: Fix PR 56077


On 02/22/13 06:30, Andrey Belevantsev wrote:
Hello,

As found by Jakub and explained in the PR audit trail by Alexander, this
patch fixes the selective scheduler merge glitch of 2008 that added the
unnecessary JUMP_P check to the flush_pending_lists call.  I have
removed the check and expanded the binary negation for clarity.

The patch was tested on x86-64, ia64, and ppc64 to be safe.  The patch
should be conservatively safe at this stage as it adds more flushes and
thus more dependencies to the scheduler.  The original test is fixed,
but I don't know how to add the test checking assembly insns order to
the testsuite.

OK for trunk?

Andrey

2012-02-22  Alexander Monakov  <amonakov@ispras.ru>
         Andrey Belevantsev  <abel@ispras.ru>

     PR middle-end/56077
     * sched-deps.c (sched_analyze_insn): When reg_pending_barrier,
     flush pending lists also on non-jumps.
Can you explain how avoiding pushing the pending lists in this situation avoids coalescing the volatile stores?

Also, if we go forward with your patch, the comment related to this conditional needs to be fixed -- it still says "Flush pending lists on jumps, ...", but you've removed the jump check.

Jeff


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