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* [Bug bootstrap/18401] New: [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE
@ 2004-11-09 15:08 rearnsha at gcc dot gnu dot org
  2004-11-09 15:09 ` [Bug bootstrap/18401] " rearnsha at gcc dot gnu dot org
                   ` (8 more replies)
  0 siblings, 9 replies; 12+ messages in thread
From: rearnsha at gcc dot gnu dot org @ 2004-11-09 15:08 UTC (permalink / raw)
  To: gcc-bugs

This is a recent regression introduced with the following patch, but I
think that it's just uncovered a latent GCSE bug:

2004-11-03  Ulrich Weigand  <uweigand@de.ibm.com>

        * tree-ssa-loop-ivopts.c (get_address_cost): Offset zero does not
        cause extra costs.  Generate canonical RTL.

With the patch applied, we get the following RTL at the start of BB 25 before
GCSE starts to run:

(code_label 236 234 237 25 38 "" [1 uses])

(note 237 236 239 25 [bb 25] NOTE_INSN_BASIC_BLOCK)

(insn 239 237 240 25 (set (reg/f:SI 154 [ D.28277 ])
        (const:SI (plus:SI (symbol_ref:SI ("^all_cores") <var_decl 0x4062d740
all_cores>)
                (const_int 20 [0x14])))) 143 {*arm_movsi_insn} (nil)
    (nil))

(insn 240 239 241 25 (set (reg/v/f:SI 172 [ sel ])
        (plus:SI (reg:SI 156 [ ivtmp.895 ])
            (reg/f:SI 154 [ D.28277 ]))) 4 {*arm_addsi3} (nil)
    (nil))

(insn 241 240 243 25 (set (reg/f:SI 155 [ D.28275 ])
        (reg/f:SI 154 [ D.28277 ])) 143 {*arm_movsi_insn} (nil)
    (expr_list:REG_EQUAL (const:SI (plus:SI (symbol_ref:SI ("^all_cores")
<var_decl 0x4062d740 all_cores>)
                (const_int 20 [0x14])))
        (nil)))

GCSE converts this to

(code_label 236 234 237 26 38 "" [1 uses])

(note 237 236 1578 26 [bb 26] NOTE_INSN_BASIC_BLOCK)

(insn 1578 237 240 26 (set (reg/f:SI 154 [ D.28277 ])
        (const:SI (plus:SI (symbol_ref:SI ("^all_cores") <var_decl 0x4062d740
all_cores>)
                (const_int 20 [0x14])))) 143 {*arm_movsi_insn} (nil)
    (expr_list:REG_EQUAL (const:SI (plus:SI (symbol_ref:SI ("^all_cores")
<var_decl 0x4062d740 all_cores>)
                (const_int 20 [0x14])))
        (nil)))

(insn 240 1578 241 26 (set (reg/v/f:SI 172 [ sel ])
        (plus:SI (reg:SI 156 [ ivtmp.895 ])
            (reg/f:SI 677 [ D.28277 ]))) 4 {*arm_addsi3} (nil)
    (expr_list:REG_EQUAL (plus:SI (reg:SI 156 [ ivtmp.895 ])
            (const:SI (plus:SI (symbol_ref:SI ("^all_cores") <var_decl
0x4062d740 all_cores>)
                    (const_int 20 [0x14]))))
        (nil)))

(insn 241 240 1666 26 (set (reg/f:SI 677 [ D.28277 ])
        (reg/f:SI 154 [ D.28277 ])) 143 {*arm_movsi_insn} (nil)
    (expr_list:REG_EQUAL (const:SI (plus:SI (symbol_ref:SI ("^all_cores")
<var_decl 0x4062d740 all_cores>)
                (const_int 20 [0x14])))
        (nil)))

But note that now the second real insn uses pseudo 677 which isn't set
until the following instruction.  This use before-set causes the
register to be marked live at the start of the BB.  However, we
ultimately end up deleting insn 240 entirely and this results in an
abort when we update the register life information.

-- 
           Summary: [4.0.0 Regression] Bootstrap failure on all ARM targets
                    due to incorrect GCSE
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code, build
          Severity: critical
          Priority: P1
         Component: bootstrap
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rearnsha at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org,law at redhat dot com
GCC target triplet: arm-linux, arm-netbsdelf, arm-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [Bug bootstrap/18401] [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE
  2004-11-09 15:08 [Bug bootstrap/18401] New: [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE rearnsha at gcc dot gnu dot org
@ 2004-11-09 15:09 ` rearnsha at gcc dot gnu dot org
  2004-11-09 15:10 ` pinskia at gcc dot gnu dot org
                   ` (7 subsequent siblings)
  8 siblings, 0 replies; 12+ messages in thread
From: rearnsha at gcc dot gnu dot org @ 2004-11-09 15:09 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From rearnsha at gcc dot gnu dot org  2004-11-09 15:09 -------
Created an attachment (id=7504)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=7504&action=view)
Testcase


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [Bug bootstrap/18401] [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE
  2004-11-09 15:08 [Bug bootstrap/18401] New: [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE rearnsha at gcc dot gnu dot org
  2004-11-09 15:09 ` [Bug bootstrap/18401] " rearnsha at gcc dot gnu dot org
@ 2004-11-09 15:10 ` pinskia at gcc dot gnu dot org
  2004-11-09 15:47 ` rearnsha at gcc dot gnu dot org
                   ` (6 subsequent siblings)
  8 siblings, 0 replies; 12+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-11-09 15:10 UTC (permalink / raw)
  To: gcc-bugs



-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org
   Target Milestone|---                         |4.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [Bug bootstrap/18401] [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE
  2004-11-09 15:08 [Bug bootstrap/18401] New: [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE rearnsha at gcc dot gnu dot org
  2004-11-09 15:09 ` [Bug bootstrap/18401] " rearnsha at gcc dot gnu dot org
  2004-11-09 15:10 ` pinskia at gcc dot gnu dot org
@ 2004-11-09 15:47 ` rearnsha at gcc dot gnu dot org
  2004-11-09 17:55 ` [Bug rtl-optimization/18401] " pinskia at gcc dot gnu dot org
                   ` (5 subsequent siblings)
  8 siblings, 0 replies; 12+ messages in thread
From: rearnsha at gcc dot gnu dot org @ 2004-11-09 15:47 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From rearnsha at gcc dot gnu dot org  2004-11-09 15:47 -------
Subject: Re:  [4.0.0 Regression] Bootstrap failure on
	all ARM targets due to incorrect GCSE

On Tue, 2004-11-09 at 15:09, rearnsha at gcc dot gnu dot org wrote:
> ------- Additional Comments From rearnsha at gcc dot gnu dot org  2004-11-09 15:09 -------
> Created an attachment (id=7504)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=7504&action=view)
>  --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=7504&action=view)
> Testcase

Just a note that the bug can be triggered with the filed testcase on an
arm-elf cross using flags '-O2'.




-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [Bug rtl-optimization/18401] [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE
  2004-11-09 15:08 [Bug bootstrap/18401] New: [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE rearnsha at gcc dot gnu dot org
                   ` (2 preceding siblings ...)
  2004-11-09 15:47 ` rearnsha at gcc dot gnu dot org
@ 2004-11-09 17:55 ` pinskia at gcc dot gnu dot org
  2004-12-12 22:10 ` pinskia at gcc dot gnu dot org
                   ` (4 subsequent siblings)
  8 siblings, 0 replies; 12+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-11-09 17:55 UTC (permalink / raw)
  To: gcc-bugs



-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|bootstrap                   |rtl-optimization


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [Bug rtl-optimization/18401] [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE
  2004-11-09 15:08 [Bug bootstrap/18401] New: [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE rearnsha at gcc dot gnu dot org
                   ` (3 preceding siblings ...)
  2004-11-09 17:55 ` [Bug rtl-optimization/18401] " pinskia at gcc dot gnu dot org
@ 2004-12-12 22:10 ` pinskia at gcc dot gnu dot org
  2004-12-13  9:54 ` rearnsha at gcc dot gnu dot org
                   ` (3 subsequent siblings)
  8 siblings, 0 replies; 12+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-12-12 22:10 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From pinskia at gcc dot gnu dot org  2004-12-12 22:10 -------
I cannot reproduce it with today's mainline, is this fixed or latent again?

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [Bug rtl-optimization/18401] [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE
  2004-11-09 15:08 [Bug bootstrap/18401] New: [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE rearnsha at gcc dot gnu dot org
                   ` (4 preceding siblings ...)
  2004-12-12 22:10 ` pinskia at gcc dot gnu dot org
@ 2004-12-13  9:54 ` rearnsha at gcc dot gnu dot org
  2004-12-22 13:03 ` steven at gcc dot gnu dot org
                   ` (2 subsequent siblings)
  8 siblings, 0 replies; 12+ messages in thread
From: rearnsha at gcc dot gnu dot org @ 2004-12-13  9:54 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From rearnsha at gcc dot gnu dot org  2004-12-13 09:54 -------
Subject: Re:  [4.0.0 Regression] Bootstrap
	failure on all ARM targets due to incorrect GCSE

On Sun, 2004-12-12 at 22:10, pinskia at gcc dot gnu dot org wrote:
> ------- Additional Comments From pinskia at gcc dot gnu dot org  2004-12-12 22:10 -------
> I cannot reproduce it with today's mainline, is this fixed or latent again?

Don't know.  It seemed to disappear again fairly quickly, but I never
saw any patch proposed that might have directly addressed the issue.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [Bug rtl-optimization/18401] [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE
  2004-11-09 15:08 [Bug bootstrap/18401] New: [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE rearnsha at gcc dot gnu dot org
                   ` (5 preceding siblings ...)
  2004-12-13  9:54 ` rearnsha at gcc dot gnu dot org
@ 2004-12-22 13:03 ` steven at gcc dot gnu dot org
  2005-01-05 19:00 ` rearnsha at gcc dot gnu dot org
  2005-01-05 19:05 ` [Bug rtl-optimization/18401] " pinskia at gcc dot gnu dot org
  8 siblings, 0 replies; 12+ messages in thread
From: steven at gcc dot gnu dot org @ 2004-12-22 13:03 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From steven at gcc dot gnu dot org  2004-12-22 13:03 -------
If only we had unit testing...

Richard, you think you can figure out when this problem *disappeared*?  Maybe
it was one of the many bitmaps changes, and there really is no GCSE bug.  If
there is a real GCSE bug, I would think we'd have found it much earlier.  But
if some unrelated patch fixed the bug, I'll build a 2004-11-03 i686-x-arm
compiler and see if I can figure out what is going on...



-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [Bug rtl-optimization/18401] [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE
  2004-11-09 15:08 [Bug bootstrap/18401] New: [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE rearnsha at gcc dot gnu dot org
                   ` (6 preceding siblings ...)
  2004-12-22 13:03 ` steven at gcc dot gnu dot org
@ 2005-01-05 19:00 ` rearnsha at gcc dot gnu dot org
  2005-01-05 19:05 ` [Bug rtl-optimization/18401] " pinskia at gcc dot gnu dot org
  8 siblings, 0 replies; 12+ messages in thread
From: rearnsha at gcc dot gnu dot org @ 2005-01-05 19:00 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From rearnsha at gcc dot gnu dot org  2005-01-05 19:00 -------
It went away after this patch:

2004-11-10  Zdenek Dvorak  <dvorakz@suse.cz>

        * tree-ssa-loop-ivopts.c (get_address_cost): Add address elements in
        right order.
        (force_var_cost): Determine cost of addition and multiplication more
        precisely.
        (get_computation_cost_at): Add cost for computing address elements to
        the final cost.

        * fold-const.c (fold): Attempt to use ptr_difference_const whenever
        one of the arguments of MINUS_EXPR is an address.
        (split_address_to_core_and_offset): New function.
        (ptr_difference_const): Handle case when one of the operands is a
        pointer.
        * tree-ssa-loop-ivopts.c (determine_base_object): Fold &*addr.
        (ptr_difference_cost): Pass addresses instead of objects to
        ptr_difference_const.

So I suspect it might have gone latent again, but it might be that it was fixed
by the canonicalization change to get_address_cost and that the problem can only
occur with RTL that is not in correct canonical form.

For reference here are the links to the two patch proposals:

http://gcc.gnu.org/ml/gcc-patches/2004-11/msg00610.html
http://gcc.gnu.org/ml/gcc-patches/2004-11/msg00715.html

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [Bug rtl-optimization/18401] Bootstrap failure on all ARM targets due to incorrect GCSE
  2004-11-09 15:08 [Bug bootstrap/18401] New: [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE rearnsha at gcc dot gnu dot org
                   ` (7 preceding siblings ...)
  2005-01-05 19:00 ` rearnsha at gcc dot gnu dot org
@ 2005-01-05 19:05 ` pinskia at gcc dot gnu dot org
  8 siblings, 0 replies; 12+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-01-05 19:05 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-05 19:05 -------
Lets remove the regression marker for now and confirm it as it is latent but not reproducible.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|critical                    |normal
             Status|WAITING                     |NEW
     Ever Confirmed|                            |1
           Keywords|build                       |
   Last reconfirmed|0000-00-00 00:00:00         |2005-01-05 19:05:05
               date|                            |
            Summary|[4.0.0 Regression] Bootstrap|Bootstrap failure on all ARM
                   |failure on all ARM targets  |targets due to incorrect
                   |due to incorrect GCSE       |GCSE
   Target Milestone|4.0.0                       |---


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [Bug rtl-optimization/18401] Bootstrap failure on all ARM targets due to incorrect GCSE
       [not found] <bug-18401-374@http.gcc.gnu.org/bugzilla/>
  2007-01-09  5:42 ` jbuck at gcc dot gnu dot org
@ 2010-04-24 12:43 ` rearnsha at gcc dot gnu dot org
  1 sibling, 0 replies; 12+ messages in thread
From: rearnsha at gcc dot gnu dot org @ 2010-04-24 12:43 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #9 from rearnsha at gcc dot gnu dot org  2010-04-24 12:43 -------
Not seen this again in a long time, so closing as works for me.


-- 

rearnsha at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |WORKSFORME


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
* [Bug rtl-optimization/18401] Bootstrap failure on all ARM targets due to incorrect GCSE
       [not found] <bug-18401-374@http.gcc.gnu.org/bugzilla/>
@ 2007-01-09  5:42 ` jbuck at gcc dot gnu dot org
  2010-04-24 12:43 ` rearnsha at gcc dot gnu dot org
  1 sibling, 0 replies; 12+ messages in thread
From: jbuck at gcc dot gnu dot org @ 2007-01-09  5:42 UTC (permalink / raw)
  To: gcc-bugs



------- Comment #8 from jbuck at gcc dot gnu dot org  2007-01-09 05:42 -------
If it is "latent but not reproducible" it shouldn't be a P1.  Downgrading.


-- 

jbuck at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P1                          |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18401


^ permalink raw reply	[flat|nested] 12+ messages in thread
end of thread, other threads:[~2010-04-24 12:43 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2004-11-09 15:08 [Bug bootstrap/18401] New: [4.0.0 Regression] Bootstrap failure on all ARM targets due to incorrect GCSE rearnsha at gcc dot gnu dot org
2004-11-09 15:09 ` [Bug bootstrap/18401] " rearnsha at gcc dot gnu dot org
2004-11-09 15:10 ` pinskia at gcc dot gnu dot org
2004-11-09 15:47 ` rearnsha at gcc dot gnu dot org
2004-11-09 17:55 ` [Bug rtl-optimization/18401] " pinskia at gcc dot gnu dot org
2004-12-12 22:10 ` pinskia at gcc dot gnu dot org
2004-12-13  9:54 ` rearnsha at gcc dot gnu dot org
2004-12-22 13:03 ` steven at gcc dot gnu dot org
2005-01-05 19:00 ` rearnsha at gcc dot gnu dot org
2005-01-05 19:05 ` [Bug rtl-optimization/18401] " pinskia at gcc dot gnu dot org
     [not found] <bug-18401-374@http.gcc.gnu.org/bugzilla/>
2007-01-09  5:42 ` jbuck at gcc dot gnu dot org
2010-04-24 12:43 ` rearnsha at gcc dot gnu dot org

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