* [Bug target/65810] powerpc64 libgfortran alignment issue?
2015-04-20 0:10 [Bug target/65810] New: powerpc64 libgfortran alignment issue? amodra at gmail dot com
@ 2015-04-20 1:43 ` jvdelisle at gcc dot gnu.org
2015-04-20 2:15 ` bergner at gcc dot gnu.org
` (6 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: jvdelisle at gcc dot gnu.org @ 2015-04-20 1:43 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65810
Jerry DeLisle <jvdelisle at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jvdelisle at gcc dot gnu.org
--- Comment #1 from Jerry DeLisle <jvdelisle at gcc dot gnu.org> ---
Could you post the output of: gfortran -v so we can confirm the version number.
I am not seeing it show up on any of the automatic testers. I tried to access
the Power7 machine I usually use and can't get in (comm problems).
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/65810] powerpc64 libgfortran alignment issue?
2015-04-20 0:10 [Bug target/65810] New: powerpc64 libgfortran alignment issue? amodra at gmail dot com
2015-04-20 1:43 ` [Bug target/65810] " jvdelisle at gcc dot gnu.org
@ 2015-04-20 2:15 ` bergner at gcc dot gnu.org
2015-04-20 3:14 ` amodra at gmail dot com
` (5 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: bergner at gcc dot gnu.org @ 2015-04-20 2:15 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65810
--- Comment #2 from Peter Bergner <bergner at gcc dot gnu.org> ---
(In reply to Jerry DeLisle from comment #1)
> I am not seeing it show up on any of the automatic testers. I tried to
> access the Power7 machine I usually use and can't get in (comm problems).
There is the gcc110 GCC compiler farm power7 system.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/65810] powerpc64 libgfortran alignment issue?
2015-04-20 0:10 [Bug target/65810] New: powerpc64 libgfortran alignment issue? amodra at gmail dot com
2015-04-20 1:43 ` [Bug target/65810] " jvdelisle at gcc dot gnu.org
2015-04-20 2:15 ` bergner at gcc dot gnu.org
@ 2015-04-20 3:14 ` amodra at gmail dot com
2015-04-20 5:24 ` amodra at gmail dot com
` (4 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: amodra at gmail dot com @ 2015-04-20 3:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65810
--- Comment #3 from Alan Modra <amodra at gmail dot com> ---
amodra@bns:~/build/gcc-5-virgin> gcc/gfortran -v
Using built-in specs.
COLLECT_GCC=gcc/gfortran
Target: powerpc64-linux
Configured with: /home/amodra/src/gcc-5-virgin/configure
--build=powerpc64-linux --with-cpu=power7 --disable-nls --enable-__cxa_atexit
--enable-secureplt --with-long-double-128 --enable-gnu-indirect-function
--enable-languages=all,go --enable-lto
Thread model: posix
gcc version 5.0.1 20150416 (prerelease) (GCC)
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2015-04-20 0:10 [Bug target/65810] New: powerpc64 libgfortran alignment issue? amodra at gmail dot com
` (2 preceding siblings ...)
2015-04-20 3:14 ` amodra at gmail dot com
@ 2015-04-20 5:24 ` amodra at gmail dot com
2015-04-20 9:45 ` [Bug target/65810] powerpc64 alignment of r2 insufficient for loading long-double constants dominiq at lps dot ens.fr
` (3 subsequent siblings)
7 siblings, 0 replies; 9+ messages in thread
From: amodra at gmail dot com @ 2015-04-20 5:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65810
Alan Modra <amodra at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2015-04-20
Assignee|unassigned at gcc dot gnu.org |amodra at gmail dot com
Ever confirmed|0 |1
--- Comment #4 from Alan Modra <amodra at gmail dot com> ---
Here's the bad code
0x00000fffb7f6c438 <write_float+3736>: addis r9,r2,-2
0x00000fffb7f6c43c <write_float+3740>: li r27,0
0x00000fffb7f6c440 <write_float+3744>: lfd f24,32760(r9)
0x00000fffb7f6c444 <write_float+3748>: lfd f25,-32768(r9)
It's from write_float.def:888
r *= 10;
so is supposed to be loading up 10.0L but instead gets a completely bogus low
double as seen in "d" below.
__gcc_qmul (a=1, b=0, c=10, d=-7.3968712249802237e+209)
So not something odd in libgfortran..
Hmm
p/x $r2
$31 = 0xfffb7fa1bd8
So, gcc emits toc sections with alignment of 8 bytes, which the linker
respects, leading to a toc pointer (r2) that can only be assumed to be 8 byte
aligned. This completely breaks rs6000.c:offsettable_ok_by_alignment.
My bug. Short term fix will be to limit offsettable_ok_by_alignment to 8 byte
alignment. Longer term, modify the linker to increase r2 alignment.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/65810] powerpc64 alignment of r2 insufficient for loading long-double constants
2015-04-20 0:10 [Bug target/65810] New: powerpc64 libgfortran alignment issue? amodra at gmail dot com
` (3 preceding siblings ...)
2015-04-20 5:24 ` amodra at gmail dot com
@ 2015-04-20 9:45 ` dominiq at lps dot ens.fr
2015-04-20 13:14 ` amodra at gmail dot com
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From: dominiq at lps dot ens.fr @ 2015-04-20 9:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65810
--- Comment #5 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Why is this not seen on powerpc64-unknown-linux-gnu at
https://gcc.gnu.org/ml/gcc-testresults/2015-04/msg02317.html?
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/65810] powerpc64 alignment of r2 insufficient for loading long-double constants
2015-04-20 0:10 [Bug target/65810] New: powerpc64 libgfortran alignment issue? amodra at gmail dot com
` (4 preceding siblings ...)
2015-04-20 9:45 ` [Bug target/65810] powerpc64 alignment of r2 insufficient for loading long-double constants dominiq at lps dot ens.fr
@ 2015-04-20 13:14 ` amodra at gmail dot com
2015-04-28 3:48 ` amodra at gcc dot gnu.org
2015-04-28 3:50 ` amodra at gmail dot com
7 siblings, 0 replies; 9+ messages in thread
From: amodra at gmail dot com @ 2015-04-20 13:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65810
--- Comment #6 from Alan Modra <amodra at gmail dot com> ---
It isn't seen most of the time because the failure happens only when r2 isn't
16-byte aligned (50% chance) and the r2 offset to a long double constant is
n*64k+32k-8 (0.012% chance per long double). libgfortran stores paths for
error messages in .rodata, so source path can affect placement of those long
double constants. I'm just lucky.
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/65810] powerpc64 alignment of r2 insufficient for loading long-double constants
2015-04-20 0:10 [Bug target/65810] New: powerpc64 libgfortran alignment issue? amodra at gmail dot com
` (5 preceding siblings ...)
2015-04-20 13:14 ` amodra at gmail dot com
@ 2015-04-28 3:48 ` amodra at gcc dot gnu.org
2015-04-28 3:50 ` amodra at gmail dot com
7 siblings, 0 replies; 9+ messages in thread
From: amodra at gcc dot gnu.org @ 2015-04-28 3:48 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65810
--- Comment #7 from Alan Modra <amodra at gcc dot gnu.org> ---
Author: amodra
Date: Tue Apr 28 03:47:19 2015
New Revision: 222498
URL: https://gcc.gnu.org/viewcvs?rev=222498&root=gcc&view=rev
Log:
PR target/65810
* config/rs6000/rs6000.c (POWERPC64_TOC_POINTER_ALIGNMENT): Define.
(offsettable_ok_by_alignment): Use minimum of decl and toc
pointer alignment. Replace dead code with assertion.
(use_toc_relative_ref): Add mode arg. Return false in -mcmodel=medium
case if size exceeds toc pointer alignment.
(rs6000_legitimize_reload_address): Update use_toc_relative_ref call.
(rs6000_emit_move): Likewise.
* configure.ac: Add linker toc pointer alignment check.
* configure: Regenerate.
* config.in: Regenerate.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/config.in
trunk/gcc/config/rs6000/rs6000.c
trunk/gcc/configure
trunk/gcc/configure.ac
^ permalink raw reply [flat|nested] 9+ messages in thread* [Bug target/65810] powerpc64 alignment of r2 insufficient for loading long-double constants
2015-04-20 0:10 [Bug target/65810] New: powerpc64 libgfortran alignment issue? amodra at gmail dot com
` (6 preceding siblings ...)
2015-04-28 3:48 ` amodra at gcc dot gnu.org
@ 2015-04-28 3:50 ` amodra at gmail dot com
7 siblings, 0 replies; 9+ messages in thread
From: amodra at gmail dot com @ 2015-04-28 3:50 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65810
Alan Modra <amodra at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
Target Milestone|--- |6.0
--- Comment #8 from Alan Modra <amodra at gmail dot com> ---
Fixed
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