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Re: GCC 3.1 Issues
Richard Henderson <rth@redhat.com> writes:
> On Sun, Mar 10, 2002 at 07:43:58AM +0100, Andreas Jaeger wrote:
>> But the inline function does not "modify memory in an unpredictable
>> fashion", we just access it.
>
> There is no implicit memory read associated with asms,
> if that's what you are asking.
>
>> So, my questions are:
>> - is the inline function correct?
>
> No. It reads from memory without representing that fact
> in any way.
>
>> - is the manual correct?
>
> Yes, but perhaps it's not as verbose as it needs to be.
So, let's improve the manual. What do you think of this minimal
patch? Or how should the paragraph get extended?
Andreas
2002-03-12 Andreas Jaeger <aj@suse.de>
* doc/extend.texi (Extended Asm): Clarify memory clobber.
============================================================
Index: gcc/doc/extend.texi
--- gcc/doc/extend.texi 2002/03/03 05:20:02 1.67
+++ gcc/doc/extend.texi 2002/03/12 06:12:39
@@ -3602,7 +3602,7 @@ represents the condition codes as a spec
condition code is handled differently, and specifying @samp{cc} has no
effect. But it is valid no matter what the machine.
-If your assembler instruction modifies memory in an unpredictable
+If your assembler instruction access memory in an unpredictable
fashion, add @samp{memory} to the list of clobbered registers. This
will cause GCC to not keep memory values cached in registers across
the assembler instruction. You will also want to add the
--
Andreas Jaeger
SuSE Labs aj@suse.de
private aj@arthur.inka.de
http://www.suse.de/~aj