[Bug rtl-optimization/25677] New: [4.2 regression] testsuite failure:gcc.c-torture/execute/960802-1.c -O1 and -O2

[Bug rtl-optimization/25677] New: [4.2 regression] testsuite failure:gcc.c-torture/execute/960802-1.c -O1 and -O2

[hp at gcc dot gnu dot org]

Last known to work with: "Mon Dec 12 22:04:54 UTC 2005 (revision 108426M)".
Known to fail with: "Mon Jan  2 13:08:54 UTC 2006 (revision 109236M)":

Running
/home/hp/combined/combined/gcc/testsuite/gcc.c-torture/execute/execute.exp ...
FAIL: gcc.c-torture/execute/960802-1.c execution,  -O1
FAIL: gcc.c-torture/execute/960802-1.c execution,  -O2

With the message in gcc.log showing an abort call.
The assembly code acts as if the line
 v = (v & 0x00ffffff) | (o & 0xff000000);
was
 v = o;
(actually there are no instructions which is the same as passing on the
return value from the previous call as the first parameter in this ABI.)
Looking at the RTL dumps, it seems combine is at fault; all the bit fiddling
is gone.
As there has been changes in this area after Jan 2, I expect it to have been
fixed but it seemed proper to add this PR before updating.
I assign it to myself until I've checked whether it remains, so no-one is
tempted to do a wild goose chase.


-- 
           Summary: [4.2 regression] testsuite failure:gcc.c-
                    torture/execute/960802-1.c -O1 and -O2
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: hp at gcc dot gnu dot org
        ReportedBy: hp at gcc dot gnu dot org
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: cris-axis-elf, cris-axis-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25677

[Bug rtl-optimization/25677] [4.2 regression] testsuite failure:gcc.c-torture/execute/960802-1.c -O1 and -O2

[hp at gcc dot gnu dot org]

------- Comment #1 from hp at gcc dot gnu dot org  2006-01-05 15:08 -------
It's still there LAST_UPDATED "Thu Jan  5 03:26:35 UTC 2006 (revision
109371M)",
so I unassign myself, at least temporarily.
Bonzini, a comment?


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hp at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bonzini at gnu dot org
         AssignedTo|hp at gcc dot gnu dot org   |unassigned at gcc dot gnu
                   |                            |dot org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2006-01-05 15:08:50
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25677

[Bug rtl-optimization/25677] [4.2 regression] testsuite failure:gcc.c-torture/execute/960802-1.c -O1 and -O2

[bonzini at gnu dot org]

------- Comment #2 from bonzini at gnu dot org  2006-01-05 15:10 -------
If it's still there, assign it to me.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25677

[Bug rtl-optimization/25677] [4.2 regression] testsuite failure:gcc.c-torture/execute/960802-1.c -O1 and -O2

[hp at gcc dot gnu dot org]

------- Comment #3 from hp at gcc dot gnu dot org  2006-01-05 15:51 -------
As offered in comment #2. Thanks!


-- 

hp at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |bonzini at gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25677

[Bug rtl-optimization/25677] [4.2 regression] testsuite failure:gcc.c-torture/execute/960802-1.c -O1 and -O2

[bonzini at gnu dot org]

------- Comment #5 from bonzini at gnu dot org  2006-01-05 16:59 -------
Created an attachment (id=10585)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10585&action=view)
patch to try


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25677

[Bug rtl-optimization/25677] [4.2 regression] testsuite failure:gcc.c-torture/execute/960802-1.c -O1 and -O2

[bonzini at gnu dot org]

------- Comment #4 from bonzini at gnu dot org  2006-01-05 16:59 -------
Combine does not try to combine across a call.  But it does not invalidate
equivalences and, in this case, it tries to replace v (the result of a function
call) with the return value register... even though in the meanwhile a
different function call has clobbered it.

H-P can you please run an assembly language comparison on this patch, to check
that it does not pessimize anything?

I think the bug is latent in other branches as well.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25677

[Bug rtl-optimization/25677] [4.2 regression] testsuite failure:gcc.c-torture/execute/960802-1.c -O1 and -O2

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org
   Target Milestone|---                         |4.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25677

[Bug rtl-optimization/25677] [4.2 regression] testsuite failure:gcc.c-torture/execute/960802-1.c -O1 and -O2

[hp at gcc dot gnu dot org]

------- Comment #6 from hp at gcc dot gnu dot org  2006-01-07 00:02 -------
I built and checked cross from i686-pc-linux-gnu to cris-axis-linux-gnu with
this
patch, and built CSiBE-2.1.1 at -O0, -O1, -O2 (note 1) and -O3 compile-time
tests and -Os compile-time and size tests, with just the two expected
differences in the generated code (using the previously posted unrandomization
and asm-wrapper patches).
Thanks!

(note 1: fails to compile -O2: invalid assembly code is generated for
linux-2.4.23-pre3-testplatform/net/ipv4/tcp_input.c at -O2 with and without
the patch due to a different bug)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25677

[Bug rtl-optimization/25677] [4.2 regression] testsuite failure:gcc.c-torture/execute/960802-1.c -O1 and -O2

[bonzini at gnu dot org]

------- Comment #7 from bonzini at gnu dot org  2006-01-16 18:21 -------
Patch committed


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bonzini at gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25677