[Bug debug/45673] New: -fcompare-debug failure with minor difference in dumps

[Bug debug/45673] New: -fcompare-debug failure with minor difference in dumps

[zsojka at seznam dot cz]

Command line:
$ gcc -O3 -fcompare-debug -march=amdfam10 ada-langn.i
or
$ gcc -O2 -fcompare-debug -finline-functions -fipa-cp-clone
-fkeep-inline-functions  ada-langn.i
(I am not able to reproduce it with these flags anymore)
or
$ gcc -O1 -fgcse -finline-small-functions -foptimize-sibling-calls -ftree-pre
-ftree-switch-conversion -ftree-vrp -fpartial-inlining -finline-functions
-fkeep-inline-functions -fcompare-debug ada-langn.i

The difference in dumps is small:
$ diff *gkd
107804c107804
<                 (const_int 32 [0x20])) [ MEM[(struct type *)0B].main_type+0
S8 A64])) ada-langn.i:15638# {*movdi_internal_rex64}
---
>                 (const_int 32 [0x20])) [ 0B->main_type+0 S8 A64])) ada-langn.i:15638# {*movdi_internal_rex64}

"MEM[(struct type *)0B]." <=> "0B->"

Tested revision:
r164287 - fail
r164280 - fail
r164228 - fail


-- 
           Summary: -fcompare-debug failure with minor difference in dumps
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: zsojka at seznam dot cz
  GCC host triplet: x86_64-pc-linux-gnu
GCC target triplet: x86_64-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45673

[Bug debug/45673] -fcompare-debug failure with minor difference in dumps

[zsojka at seznam dot cz]

------- Comment #1 from zsojka at seznam dot cz  2010-09-14 23:43 -------
Created an attachment (id=21797)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=21797&action=view)
testcase, preprocessed ada-lang.c from GDB (licensed under GPLv2)

Reducing is very slow, after 4 hours of delta run I got to ~16000 lines. So I
am uploading the original testcase.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45673

[Bug debug/45673] -fcompare-debug failure with minor difference in dumps

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2010-09-15 09:49 -------
Another dumping artifact probably.  At some point I'd like to dump all
MEM_REFs as MEM[(...)p + cst] and drop the fancy ways.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45673

[Bug debug/45673] -fcompare-debug failure with minor difference in dumps

[aoliva at gcc dot gnu dot org]

------- Comment #3 from aoliva at gcc dot gnu dot org  2010-09-21 08:02 -------
Mine


-- 

aoliva at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |aoliva at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2010-09-21 08:02:06
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45673

[Bug debug/45673] -fcompare-debug failure with minor difference in dumps

[aoliva at gcc dot gnu dot org]

------- Comment #4 from aoliva at gcc dot gnu dot org  2010-09-21 08:53 -------
Created an attachment (id=21854)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=21854&action=view)
Patch that fixes the problem

Here's the patch I'm testing.  Turns out it's not enough to take only the
second pointer type into account, the first also matters because we'll get
different dump output depending on whether they're equal or not.  In this case,
we failed to distinguish (void*)0B and (struct type*)0B in the first operands. 
Richi, care to pre-approve it in case it passes regstrap?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45673