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From: Daniel Jacobowitz <dan@codesourcery.com>
To: Ulrich Weigand <uweigand@de.ibm.com>
Cc: Ken Werner <ken@linux.vnet.ibm.com>,
	gdb-patches@sourceware.org,
	Joel Brobecker <brobecker@adacore.com>
Subject: Re: [patch] fix pre-/post- in-/decrement
Date: Mon, 04 Oct 2010 22:59:00 -0000	[thread overview]
Message-ID: <20101004225938.GZ6985@caradoc.them.org> (raw)
In-Reply-To: <201010042157.o94LvlhY018611@d12av02.megacenter.de.ibm.com>

On Mon, Oct 04, 2010 at 11:57:47PM +0200, Ulrich Weigand wrote:
> It would appear that even the current behavior, as shown in your trace,
> already contains an unnecessary load.  There should be no need to perform
> a memory read to evaluate "print *$p = 1".

In fact, we rely on this unintuitive behavior.  If you write to any
kind of memory other than RAM, then it's not possible for GDB to
predict what value was actually written.  Suppose you write a value to
ROM with "print"; GDB should show the old value, to reflect that the
variable was not modified.

I can't think of a good way to test this other than by matching debug
output...

-- 
Daniel Jacobowitz
CodeSourcery


  reply	other threads:[~2010-10-04 22:59 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-17 12:58 [patch] GNU vector unop support Ken Werner
2010-09-28 16:04 ` Ken Werner
     [not found] ` <20100930185634.GC6213@adacore.com>
2010-10-01 17:45   ` [patch] fix pre-/post- in-/decrement Ken Werner
2010-10-04 13:01     ` Ulrich Weigand
2010-10-04 19:47       ` Ken Werner
2010-10-04 20:45         ` Daniel Jacobowitz
2010-10-04 21:58           ` Ulrich Weigand
2010-10-04 22:59             ` Daniel Jacobowitz [this message]
2010-10-04 23:25               ` Ulrich Weigand
2010-10-05  1:17                 ` Daniel Jacobowitz
2010-10-05 13:28                   ` Ulrich Weigand
2010-10-05 13:42                     ` Daniel Jacobowitz
2010-10-06 18:59                       ` [rfc] Fix value_assign return value (Re: [patch] fix pre-/post- in-/decrement) Ulrich Weigand
2010-10-26 13:42                         ` Daniel Jacobowitz
2010-12-01 16:51                           ` Ulrich Weigand
2010-10-06 20:55                       ` [patch] fix pre-/post- in-/decrement Vladimir Prus
2010-10-07 12:38         ` Ken Werner
2010-10-12 23:00           ` Tom Tromey
2010-10-13  8:45             ` Andreas Schwab
2010-10-13  9:23             ` Ken Werner
2010-10-13 16:07               ` Daniel Jacobowitz
2010-10-13 19:01               ` Tom Tromey
2010-10-19  7:38                 ` Ken Werner
2010-11-02  8:23                   ` Ken Werner
2010-11-02 20:31                   ` Tom Tromey
2010-11-03 13:52                     ` Ken Werner
2010-10-04 20:52   ` [patch] GNU vector unop support Ken Werner
2010-10-06 23:27     ` Joel Brobecker
2010-10-07 16:23       ` Ken Werner
2010-11-03 14:07       ` Ken Werner

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