* [Bug bootstrap/44255] [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64
2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
@ 2010-05-23 20:07 ` rguenth at gcc dot gnu dot org
2010-05-23 21:09 ` [Bug bootstrap/44255] [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 and arm mikpe at it dot uu dot se
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From: rguenth at gcc dot gnu dot org @ 2010-05-23 20:07 UTC (permalink / raw)
To: gcc-bugs
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |4.6.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
^ permalink raw reply [flat|nested] 16+ messages in thread* [Bug bootstrap/44255] [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 and arm
2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
2010-05-23 20:07 ` [Bug bootstrap/44255] " rguenth at gcc dot gnu dot org
@ 2010-05-23 21:09 ` mikpe at it dot uu dot se
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From: mikpe at it dot uu dot se @ 2010-05-23 21:09 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from mikpe at it dot uu dot se 2010-05-23 21:09 -------
The exact same bootstrap comparison failure now also showed up in my attempt to
build gcc-4.6-20100522 on armv5tel-unknown-linux-gnueabi. And like sparc64 the
previous 4.6 weekly snapshot bootstrapped fine.
--
mikpe at it dot uu dot se changed:
What |Removed |Added
----------------------------------------------------------------------------
GCC build triplet|sparc64-unknown-linux-gnu |sparc64-unknown-linux-gnu,
| |armv5tel-unknown-linux-
| |gnueabi
GCC host triplet|sparc64-unknown-linux-gnu |sparc64-unknown-linux-gnu,
| |armv5tel-unknown-linux-
| |gnueabi
GCC target triplet|sparc64-unknown-linux-gnu |sparc64-unknown-linux-gnu,
| |armv5tel-unknown-linux-
| |gnueabi
Summary|[4.6 regression] gcc-4.6- |[4.6 regression] gcc-4.6-
|20100522 bootstrap |20100522 bootstrap
|comparison failure on |comparison failure on
|sparc64 |sparc64 and arm
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
2010-05-23 20:07 ` [Bug bootstrap/44255] " rguenth at gcc dot gnu dot org
2010-05-23 21:09 ` [Bug bootstrap/44255] [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 and arm mikpe at it dot uu dot se
@ 2010-05-24 9:31 ` mikpe at it dot uu dot se
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From: mikpe at it dot uu dot se @ 2010-05-24 9:31 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from mikpe at it dot uu dot se 2010-05-24 09:31 -------
Bisection identified r159600 as the source of the failure on sparc64:
Author: rsandifo
Date: Wed May 19 21:08:53 2010
New Revision: 159600
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=159600
Log:
gcc/
* combine.c (propagate_for_debug): Call make_compound_operation
on the source value.
(try_combine): When implementing a split chosen by find_split_point,
either copy i2src or set it to null. Assert that i2src is not null
before substituting into CALL_INSN_FUNCTION_USAGE.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/combine.c
The corresponding gcc-patches thread started here:
http://gcc.gnu.org/ml/gcc-patches/2010-05/msg01296.html
My ARM box is currently busy running another test, but as soon as that finishes
I'll check if r159600 is also responsible for the ARM bootstrap failure.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
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From: iains at gcc dot gnu dot org @ 2010-05-24 11:46 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from iains at gcc dot gnu dot org 2010-05-24 11:46 -------
most likely this is a duplicate of:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44229
and potentially an LE/BE issue given that it's not reported on *x86*
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
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From: mikpe at it dot uu dot se @ 2010-05-24 16:16 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from mikpe at it dot uu dot se 2010-05-24 16:16 -------
(In reply to comment #3)
> most likely this is a duplicate of:
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44229
>
> and potentially an LE/BE issue given that it's not reported on *x86*
However:
1. I see the failure on both BE (sparc64) and LE (armv5tel).
2. Both BE (powerpc64-linux) and LE (x86) don't see the failure.
So I doubt it's an endianess issue.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
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From: mikpe at it dot uu dot se @ 2010-05-24 16:22 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from mikpe at it dot uu dot se 2010-05-24 16:21 -------
Comparing stage2-libiberty/cp-demangle.o with stage3-libiberty/cp-demangle.o
shows that one instruction has had it's source operands swapped:
> objdump -d stage2-libiberty/cp-demangle.o > a
> objdump -d stage3-libiberty/cp-demangle.o > b
> diff -u a b
--- a 2010-05-24 17:59:49.000000000 +0200
+++ b 2010-05-24 17:59:54.000000000 +0200
@@ -1,5 +1,5 @@
-stage2-libiberty/cp-demangle.o: file format elf32-sparc
+stage3-libiberty/cp-demangle.o: file format elf32-sparc
Disassembly of section .text:
@@ -4702,7 +4702,7 @@
5078: 89 29 20 04 sll %g4, 4, %g4
507c: 84 00 80 04 add %g2, %g4, %g2
5080: 84 00 b8 6c add %g2, -1940, %g2
- 5084: 84 80 80 03 addcc %g2, %g3, %g2
+ 5084: 84 80 c0 02 addcc %g3, %g2, %g2
5088: 22 80 02 11 be,a 58cc <cplus_demangle_type+0xa20>
508c: c4 00 a0 04 ld [ %g2 + 4 ], %g2
5090: c6 06 20 14 ld [ %i0 + 0x14 ], %g3
Now, the code is still correct, but gcc shouldn't arbitrarily change it's mind
like this in stage3. Hence I suspect r159600 introduces some non-determinism,
or exposes latent non-determinism.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
^ permalink raw reply [flat|nested] 16+ messages in thread* [Bug bootstrap/44255] [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 and arm
2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
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From: mikpe at it dot uu dot se @ 2010-05-24 22:24 UTC (permalink / raw)
To: gcc-bugs
------- Comment #6 from mikpe at it dot uu dot se 2010-05-24 22:24 -------
The stage 3 comparison failure on ARM is as follows:
...
Bootstrap comparison failure!
libiberty/pic/cp-demangle.o differs
Comparing the disassembly listings of prev-libiberty/pic/cp-demangle.o and
libiberty/pic/cp-demangle.o yields:
@@ -1,5 +1,5 @@
-prev-libiberty/pic/cp-demangle.o: file format elf32-littlearm
+libiberty/pic/cp-demangle.o: file format elf32-littlearm
Disassembly of section .text:
@@ -4751,12 +4751,12 @@
4954: e58d0004 str r0, [sp, #4]
4958: eaffffe7 b 48fc <cplus_demangle_type+0x21c>
495c: e3a01014 mov r1, #20 ; 0x14
- 4960: e0010193 mul r1, r3, r1
- 4964: e59f38e8 ldr r3, [pc, #2280] ; 5254
<cplus_demangle_type+0xb74>
- 4968: e2411e79 sub r1, r1, #1936 ; 0x790
- 496c: e2411004 sub r1, r1, #4 ; 0x4
- 4970: e7923003 ldr r3, [r2, r3]
- 4974: e0913003 adds r3, r1, r3
+ 4960: e0030391 mul r3, r1, r3
+ 4964: e59f18e8 ldr r1, [pc, #2280] ; 5254
<cplus_demangle_type+0xb74>
+ 4968: e2433e79 sub r3, r3, #1936 ; 0x790
+ 496c: e2433004 sub r3, r3, #4 ; 0x4
+ 4970: e7922001 ldr r2, [r2, r1]
+ 4974: e0923003 adds r3, r2, r3
4978: 0a000215 beq 51d4 <cplus_demangle_type+0xaf4>
497c: e5942014 ldr r2, [r4, #20]
4980: e5941018 ldr r1, [r4, #24]
So it's not just two swapped source operands in an arithmetic instruction as on
sparc, but also different (still valid) register assignment.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
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From: iains at gcc dot gnu dot org @ 2010-05-25 7:38 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from iains at gcc dot gnu dot org 2010-05-25 07:38 -------
(In reply to comment #4)
> (In reply to comment #3)
> > most likely this is a duplicate of:
> > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44229
> 1. I see the failure on both BE (sparc64) and LE (armv5tel).
> 2. Both BE (powerpc64-linux) and LE (x86) don't see the failure.
No failure on powerpc64-apple-darwin9 either.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
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From: jakub at gcc dot gnu dot org @ 2010-05-25 7:58 UTC (permalink / raw)
To: gcc-bugs
------- Comment #8 from jakub at gcc dot gnu dot org 2010-05-25 07:57 -------
If cp-demangle.c fails to compile even with -fcompare-debug switch added,
please
attach preprocessed source for it from sparc64 and/or arm and mention the exact
command line switches used to compile it, so it can be reproduced with a
cross-compiler. Thanks.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
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From: rguenth at gcc dot gnu dot org @ 2010-05-25 13:27 UTC (permalink / raw)
To: gcc-bugs
------- Comment #9 from rguenth at gcc dot gnu dot org 2010-05-25 13:27 -------
*** Bug 44270 has been marked as a duplicate of this bug. ***
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |michael dot a dot richmond
| |at nasa dot gov
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
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From: mikpe at it dot uu dot se @ 2010-05-26 15:17 UTC (permalink / raw)
To: gcc-bugs
------- Comment #10 from mikpe at it dot uu dot se 2010-05-26 15:16 -------
(In reply to comment #2)
> My ARM box is currently busy running another test, but as soon as that finishes
> I'll check if r159600 is also responsible for the ARM bootstrap failure.
It is, r159599 bootstraps on ARM, r159600 does not.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
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From: mikpe at it dot uu dot se @ 2010-05-27 21:36 UTC (permalink / raw)
To: gcc-bugs
------- Comment #11 from mikpe at it dot uu dot se 2010-05-27 21:35 -------
Created an attachment (id=20763)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20763&action=view)
preprocessed source for libiberty/cp-demangle.c
Here's the preprocessed source for libiberty/cp-demangle.c as generated by
gcc-4.6-20100522 on sparc64-unknown-linux. The same 4.6 snapshot built on x86
as a cross to sparc64-unknown-linux also fails with -m32 -g -fcompare-debug
-O2:
> sparc64-unknown-linux-gcc -m32 -g -fcompare-debug -O2 -c cp-demangle.i
sparc64-unknown-linux-gcc: cp-demangle.i: -fcompare-debug failure
If you compile cp-demangle.i to .o first with -g0 and then with -g and compare
the objdump -d output from those two object files, you'll find a single
instruction difference at or near address 0x5080 in function
cplus_demangle_type ().
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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2010-05-23 15:43 [Bug bootstrap/44255] New: [4.6 regression] gcc-4.6-20100522 bootstrap comparison failure on sparc64 mikpe at it dot uu dot se
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From: jakub at gcc dot gnu dot org @ 2010-05-27 22:09 UTC (permalink / raw)
To: gcc-bugs
------- Comment #12 from jakub at gcc dot gnu dot org 2010-05-27 22:09 -------
Subject: Bug 44255
Author: jakub
Date: Thu May 27 22:08:41 2010
New Revision: 159952
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=159952
Log:
PR bootstrap/44255
* combine.c (struct rtx_subst_pair): Define unconditionally.
(propagate_for_debug_subst): Likewise. If not AUTO_INC_DEC,
copy_rtx pair->to instead of cleanup_auto_inc_dec it.
Call make_compound_operation on pair->to.
(propagate_for_debug): Don't call make_compound_operation here.
Always use simplify_replace_fn_rtx.
Modified:
trunk/gcc/ChangeLog
trunk/gcc/combine.c
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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From: mikpe at it dot uu dot se @ 2010-05-28 16:02 UTC (permalink / raw)
To: gcc-bugs
------- Comment #13 from mikpe at it dot uu dot se 2010-05-28 16:02 -------
Jakub's patch fixed 4.6 bootstrap on my sparc64 machine. My ARM is testing
other branches currently, but I should have 4.6 bootstrap results for it on
Sunday or Monday, at which time I'll close this PR if things went well.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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From: mikpe at it dot uu dot se @ 2010-05-31 7:20 UTC (permalink / raw)
To: gcc-bugs
------- Comment #14 from mikpe at it dot uu dot se 2010-05-31 07:20 -------
The bootstrap comparison failure is gone on armv5tel-unknown-linux-gnueabi with
gcc-4.6-20100529. Thus closing as fixed.
--
mikpe at it dot uu dot se changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44255
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