* [Bug tree-optimization/43236] -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails
2010-03-02 20:14 [Bug tree-optimization/43236] New: -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails zsojka at seznam dot cz
@ 2010-03-02 20:21 ` zsojka at seznam dot cz
2010-03-02 20:34 ` zsojka at seznam dot cz
` (9 subsequent siblings)
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From: zsojka at seznam dot cz @ 2010-03-02 20:21 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from zsojka at seznam dot cz 2010-03-02 20:20 -------
Created an attachment (id=20005)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20005&action=view)
this patch causes bootstrap with BOOT_CFLAGS="-O2 -ftree-loop-distribution" to
assert
Assert message is:
/mnt/svn/gcc-trunk/libgcc/../gcc/libgcc2.c: In function
‘__mulvdi3’:
/mnt/svn/gcc-trunk/libgcc/../gcc/libgcc2.c:400:1: internal compiler error: in
delete_output_reload, at reload1.c:8543
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
which is:
gcc_assert(spill_reg_store[last_reload_reg + k] == 0);
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43236
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* [Bug tree-optimization/43236] -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails
2010-03-02 20:14 [Bug tree-optimization/43236] New: -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails zsojka at seznam dot cz
2010-03-02 20:21 ` [Bug tree-optimization/43236] " zsojka at seznam dot cz
@ 2010-03-02 20:34 ` zsojka at seznam dot cz
2010-03-03 6:27 ` zsojka at seznam dot cz
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From: zsojka at seznam dot cz @ 2010-03-02 20:34 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from zsojka at seznam dot cz 2010-03-02 20:33 -------
Created an attachment (id=20006)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20006&action=view)
this patch causes regular bootstrap to assert
Assert message is:
/mnt/svn/gcc-trunk/libgcc/../gcc/libgcc2.c: In function
‘__mulvdi3’:
/mnt/svn/gcc-trunk/libgcc/../gcc/libgcc2.c:400:1: internal compiler error: in
delete_output_reload, at reload1.c:8543
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
which is:
gcc_assert(spill_reg_store[last_reload_reg + k] == 0);
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43236
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug tree-optimization/43236] -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails
2010-03-02 20:14 [Bug tree-optimization/43236] New: -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails zsojka at seznam dot cz
2010-03-02 20:21 ` [Bug tree-optimization/43236] " zsojka at seznam dot cz
2010-03-02 20:34 ` zsojka at seznam dot cz
@ 2010-03-03 6:27 ` zsojka at seznam dot cz
2010-03-03 6:31 ` zsojka at seznam dot cz
` (7 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: zsojka at seznam dot cz @ 2010-03-03 6:27 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from zsojka at seznam dot cz 2010-03-03 06:26 -------
Created an attachment (id=20008)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20008&action=view)
minimal executable testcase
Fails when compiled with -ftree-loop-distribution at all -O[123s] levels:
$ /mnt/svn/gcc-trunk/binary-157161/bin/gcc pr43236.c -O1
-ftree-loop-distribution && ./a.out
Aborted
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43236
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* [Bug tree-optimization/43236] -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails
2010-03-02 20:14 [Bug tree-optimization/43236] New: -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails zsojka at seznam dot cz
` (2 preceding siblings ...)
2010-03-03 6:27 ` zsojka at seznam dot cz
@ 2010-03-03 6:31 ` zsojka at seznam dot cz
2010-03-03 10:38 ` rguenth at gcc dot gnu dot org
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From: zsojka at seznam dot cz @ 2010-03-03 6:31 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from zsojka at seznam dot cz 2010-03-03 06:30 -------
(In reply to comment #3)
When output is uncommented, -Os shows different behaviour than -O[123] (but
still wrong):
-Os zeroes items [8] - [18]
-O[123] zeroes [9] - [18]
expected is [10] - [19]
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43236
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* [Bug tree-optimization/43236] -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails
2010-03-02 20:14 [Bug tree-optimization/43236] New: -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails zsojka at seznam dot cz
` (3 preceding siblings ...)
2010-03-03 6:31 ` zsojka at seznam dot cz
@ 2010-03-03 10:38 ` rguenth at gcc dot gnu dot org
2010-03-03 13:07 ` amonakov at gcc dot gnu dot org
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From: rguenth at gcc dot gnu dot org @ 2010-03-03 10:38 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from rguenth at gcc dot gnu dot org 2010-03-03 10:38 -------
Confirmed.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |spop at gcc dot gnu dot org
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Known to fail| |4.4.3 4.5.0
Last reconfirmed|0000-00-00 00:00:00 |2010-03-03 10:38:17
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43236
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* [Bug tree-optimization/43236] -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails
2010-03-02 20:14 [Bug tree-optimization/43236] New: -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails zsojka at seznam dot cz
` (4 preceding siblings ...)
2010-03-03 10:38 ` rguenth at gcc dot gnu dot org
@ 2010-03-03 13:07 ` amonakov at gcc dot gnu dot org
2010-03-03 13:39 ` amonakov at gcc dot gnu dot org
` (4 subsequent siblings)
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From: amonakov at gcc dot gnu dot org @ 2010-03-03 13:07 UTC (permalink / raw)
To: gcc-bugs
------- Comment #6 from amonakov at gcc dot gnu dot org 2010-03-03 13:06 -------
Not a regression, off-by-one error in reverse iteration case is since day one.
Patch:
diff --git a/gcc/tree-loop-distribution.c b/gcc/tree-loop-distribution.c
index 13ac7ea..110abdc 100644
--- a/gcc/tree-loop-distribution.c
+++ b/gcc/tree-loop-distribution.c
@@ -285,6 +285,8 @@ generate_memset_zero (gimple stmt, tree op0, tree nb_iter,
addr_base = fold_convert_loc (loc, sizetype, addr_base);
addr_base = size_binop_loc (loc, MINUS_EXPR, addr_base,
fold_convert_loc (loc, sizetype, nb_bytes));
+ addr_base = size_binop_loc (loc, PLUS_EXPR, addr_base,
+ TYPE_SIZE_UNIT (TREE_TYPE (op0)));
addr_base = fold_build2_loc (loc, POINTER_PLUS_EXPR,
TREE_TYPE (DR_BASE_ADDRESS (dr)),
DR_BASE_ADDRESS (dr), addr_base);
This fixes the -O[123] miscompilations. -Os is slightly harder to fix, since we
use wrong number of iterations (cond bb is executed 11 times, latch bb with
assignment 10 times).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43236
^ permalink raw reply [flat|nested] 12+ messages in thread
* [Bug tree-optimization/43236] -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails
2010-03-02 20:14 [Bug tree-optimization/43236] New: -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails zsojka at seznam dot cz
` (5 preceding siblings ...)
2010-03-03 13:07 ` amonakov at gcc dot gnu dot org
@ 2010-03-03 13:39 ` amonakov at gcc dot gnu dot org
2010-03-09 16:56 ` amonakov at gcc dot gnu dot org
` (3 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: amonakov at gcc dot gnu dot org @ 2010-03-03 13:39 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from amonakov at gcc dot gnu dot org 2010-03-03 13:38 -------
(In reply to comment #6)
> This fixes the -O[123] miscompilations. -Os is slightly harder to fix, since we
> use wrong number of iterations (cond bb is executed 11 times, latch bb with
> assignment 10 times).
I don't see what is the proper fix for the -Os problem. The loop structure is
as follows:
<bb2>
i = 20
goto bb4
<bb3>
i--
a[i] = 0
<bb4>
if (i > 10) goto bb3
Thus, bb4 is header, bb3 is latch, number_of_exit_cond_executions() is 11,
just_once_each_iteration_p() is true for both bb3 and bb4 (?!)
--
amonakov at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |amonakov at gcc dot gnu dot
| |org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43236
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* [Bug tree-optimization/43236] -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails
2010-03-02 20:14 [Bug tree-optimization/43236] New: -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails zsojka at seznam dot cz
` (6 preceding siblings ...)
2010-03-03 13:39 ` amonakov at gcc dot gnu dot org
@ 2010-03-09 16:56 ` amonakov at gcc dot gnu dot org
2010-03-10 12:54 ` amonakov at gcc dot gnu dot org
` (2 subsequent siblings)
10 siblings, 0 replies; 12+ messages in thread
From: amonakov at gcc dot gnu dot org @ 2010-03-09 16:56 UTC (permalink / raw)
To: gcc-bugs
------- Comment #8 from amonakov at gcc dot gnu dot org 2010-03-09 16:55 -------
Given the fact that loop distribution only works for two-bb loops, I think the
fix is to simply take number of latch executions when the stmt is in the latch.
diff --git a/gcc/tree-loop-distribution.c b/gcc/tree-loop-distribution.c
--- a/gcc/tree-loop-distribution.c
+++ b/gcc/tree-loop-distribution.c
@@ -389,6 +391,8 @@ generate_builtin (struct loop *loop, bitmap partition, bool
copy_p)
goto end;
write = stmt;
+ if (bb == loop->latch)
+ nb_iter = number_of_latch_executions (loop);
}
}
}
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43236
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* [Bug tree-optimization/43236] -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails
2010-03-02 20:14 [Bug tree-optimization/43236] New: -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails zsojka at seznam dot cz
` (7 preceding siblings ...)
2010-03-09 16:56 ` amonakov at gcc dot gnu dot org
@ 2010-03-10 12:54 ` amonakov at gcc dot gnu dot org
2010-03-10 12:57 ` amonakov at gcc dot gnu dot org
2010-03-10 14:17 ` sezeroz at gmail dot com
10 siblings, 0 replies; 12+ messages in thread
From: amonakov at gcc dot gnu dot org @ 2010-03-10 12:54 UTC (permalink / raw)
To: gcc-bugs
------- Comment #9 from amonakov at gcc dot gnu dot org 2010-03-10 12:54 -------
Subject: Bug 43236
Author: amonakov
Date: Wed Mar 10 12:53:51 2010
New Revision: 157339
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=157339
Log:
PR tree-optimization/43236
* tree-loop-distribution.c (generate_memset_zero): Fix off-by-one
error in calculation of base address in reverse iteration case.
(generate_builtin): Take number of latch executions if the statement
is in the latch.
* gcc.c-torture/execute/pr43236.c: New.
Added:
trunk/gcc/testsuite/gcc.c-torture/execute/pr43236.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/testsuite/ChangeLog
trunk/gcc/tree-loop-distribution.c
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43236
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* [Bug tree-optimization/43236] -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails
2010-03-02 20:14 [Bug tree-optimization/43236] New: -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails zsojka at seznam dot cz
` (8 preceding siblings ...)
2010-03-10 12:54 ` amonakov at gcc dot gnu dot org
@ 2010-03-10 12:57 ` amonakov at gcc dot gnu dot org
2010-03-10 14:17 ` sezeroz at gmail dot com
10 siblings, 0 replies; 12+ messages in thread
From: amonakov at gcc dot gnu dot org @ 2010-03-10 12:57 UTC (permalink / raw)
To: gcc-bugs
------- Comment #10 from amonakov at gcc dot gnu dot org 2010-03-10 12:57 -------
Both issues are fixed with above commit.
--
amonakov at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43236
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* [Bug tree-optimization/43236] -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails
2010-03-02 20:14 [Bug tree-optimization/43236] New: -ftree-loop-distribution produces wrong code in reload1.c:delete_output_reload(), bootstrap fails zsojka at seznam dot cz
` (9 preceding siblings ...)
2010-03-10 12:57 ` amonakov at gcc dot gnu dot org
@ 2010-03-10 14:17 ` sezeroz at gmail dot com
10 siblings, 0 replies; 12+ messages in thread
From: sezeroz at gmail dot com @ 2010-03-10 14:17 UTC (permalink / raw)
To: gcc-bugs
------- Comment #11 from sezeroz at gmail dot com 2010-03-10 14:17 -------
The testcase fails with 4.4 with -Ox -ftree-loop-distribution and the patch
does not apply to 4.4. Will there be a gcc-4.4 backport of this?
--
sezeroz at gmail dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |sezeroz at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43236
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