http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47556
--- Comment #2 from Jeremy Fitzhardinge 2011-01-31
22:16:54 UTC ---
Hm, yes, I see. The hand-written asm, which uses %ah, does appear to run into
false partial register stalls according to 3.5.2.3 in the Intel Optimisation
Reference Manual.
On
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47556
Summary: x86: fails to take advantage of high-byte addressing
mode
Product: gcc
Version: 4.5.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component
--- Comment #12 from jeremy at goop dot org 2009-02-09 20:37 ---
Created an attachment (id=17274)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17274&action=view)
Original code to set up hypercalls.
This is the original code Jakub distilled the reproducer from. It inc
--- Comment #10 from jeremy at goop dot org 2009-02-09 20:35 ---
The code in question is setting up parameters for a Xen hypercall. The
hypercall ABI defines what arguments go in which registers. It uses the
"register unsigned long arg asm" syntax because that's
--- Comment #10 from jeremy at goop dot org 2006-10-01 08:47 ---
>In fact if GCC changes the behavior,
>it would be for the worse as then people using them correctly would be
>punished.
How so?
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29305
--- Comment #8 from jeremy at goop dot org 2006-10-01 05:58 ---
Reopen as enhancement, in the hope gcc implements more useful semantics for
taking the address of a label.
--
jeremy at goop dot org changed:
What|Removed |Added
--- Comment #7 from jeremy at goop dot org 2006-10-01 05:55 ---
Subject: Re: local label-as-value being placed before
function prolog
pinskia at gcc dot gnu dot org wrote:
> what do you really want? Because what you have mentioned so far seems like
> you
> should be writ
--- Comment #5 from jeremy at goop dot org 2006-10-01 05:42 ---
Created an attachment (id=12363)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=12363&action=view)
More complete example of what I'm trying to do
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29305
--- Comment #4 from jeremy at goop dot org 2006-10-01 05:36 ---
Well, it isn't failing in any obvious fashion. It's quietly putting the label
at the wrong place, without complaint. The same code later in a function does
put the labels at the right place, so the failu
--- Comment #2 from jeremy at goop dot org 2006-10-01 05:18 ---
What I'm trying to do is get the address of particular faulting instructions in
an asm:
faulted: asm volatile("ud2");
so that an exception handler can come back later and match a fault address with
an in
mal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jeremy at goop dot org
GCC build triplet: i386-redhat-linux
GCC host triplet: i386-redhat-linux
GCC target triplet: i386-redhat-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29305
--- Comment #2 from jeremy at goop dot org 2006-09-30 16:46 ---
Created an attachment (id=12360)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=12360&action=view)
compile with "gcc -O -S t.c"
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29299
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jeremy at goop dot org
GCC build triplet: i386-redhat-linux
GCC host triplet: i386-redhat-linux
GCC target triplet: i386-redhat-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29299
13 matches
Mail list logo
