[Bug rtl-optimization/24883] New: [4.1 Regression] fatal error: internal consistency failure building xorg-x11

[Bug rtl-optimization/24883] New: [4.1 Regression] fatal error: internal consistency failure building xorg-x11

[rguenth at gcc dot gnu dot org]

/usr/lib/gcc/s390-suse-linux/4.1.0/cc1 -fpreprocessed reo.i -quiet -dumpbase
reo.i -m31 -mesa -march=g5 -ansi -auxbase reo -O2 -Wall -Wpointer-arith
-Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations
-Wredundant-decls -Wnested-externs -Wundef -ansi -version -fomit-frame-pointer
-fno-strict-aliasing -o /tmp/ccC1ZDOL.s
reo.c: In function ?orec_alt?:
reo.c:199: fatal error: internal consistency failure
compilation terminated.


-- 
           Summary: [4.1 Regression]  fatal error: internal consistency
                    failure building xorg-x11
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: critical
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org
GCC target triplet: s390-*-*


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1 Regression] fatal error: internal consistency failure building xorg-x11

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2005-11-15 22:03 -------
Created an attachment (id=10245)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10245&action=view)
reduced testcase

testcase


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1 Regression] fatal error: internal consistency failure building xorg-x11

[janis at gcc dot gnu dot org]

------- Comment #2 from janis at gcc dot gnu dot org  2005-11-16 19:31 -------
A regression hunt using an s390-linux cross compiler on powerpc-linux
identified the following patch:

http://gcc.gnu.org/viewcvs?view=rev&rev=103955

r103955 | ian | 2005-09-06 17:51:48 +0000 (Tue, 06 Sep 2005) | 3 lines

        * simplify-rtx.c (simplify_binary_operation_1): Correct the
        condition for detecting cases like (a&a) and (a^a).


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janis at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ian at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1 Regression] fatal error: internal consistency failure building xorg-x11

[saurabh dot verma at codito dot com]

------- Comment #3 from saurabh dot verma at codito dot com  2005-11-17 10:05 -------
Adding myself to CC list, as the offending patch was given by me


-- 

saurabh dot verma at codito dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |saurabh dot verma at codito
                   |                            |dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1 Regression] fatal error: internal consistency failure building xorg-x11

[uweigand at gcc dot gnu dot org]

------- Comment #4 from uweigand at gcc dot gnu dot org  2005-11-17 12:45 -------
It looks like the simplify-rtx patch is not really the cause of the problem,
it simply exposes a pre-existing bug in combine and/or flow.

Before combine, we have a situation that looks like (simplified):

  insn 82:  reg46 = reg49 ^ reg50  (REG_DEAD reg49)
  insn 87:  reg50 = reg46 ^ reg50  (REG_READ reg46)

Note that reg 50 is live both at the start and the end of the current
basic block.

Now, due to the improved XOR optimization in simplify-rtx, combine
recognized these insn can be combined into:

  insn 87:  reg50 = reg49          (REG_READ reg49)

And suddenly reg50 is no longer live at the start of this basic block.

Unfortunately, there appears to be no code in combine that recognizes
this fact and schedules the basic block for updating of global life
info.  (The only cases where that happens are related to moving REG_DEAD
notes, but in this situation we don't *have* a REG_DEAD note for reg50
in the first place.)

Thus, reg50 remains marked live-at-start in this basic block, and when
a later pass does a local live info update on the block, the sanity
check in verify_local_life_at_start triggers.

Right now I don't know how and where to fix this.


-- 

uweigand at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-11-17 12:45:27
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1 Regression] fatal error: internal consistency failure building xorg-x11

[ian at airs dot com]

------- Comment #5 from ian at airs dot com  2005-11-18 20:13 -------
Created an attachment (id=10277)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10277&action=view)
Patch

This patch appears to fix the problem.

However, I am about to leave for the weekend, and won't be back until Monday. 
Given that we are about to branch, I would greatly appreciate if somebody else
could run a bootstrap and testsuite run.  I will preapprove the patch if those
pass.

(Otherwise I will tackle it on Monday, but it would be nice to get it done
before then.  Thanks!)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1 Regression] fatal error: internal consistency failure building xorg-x11

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1 Regression] fatal error: internal consistency failure building xorg-x11

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2005-11-18 20:30 -------
I'll do it.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1 Regression] fatal error: internal consistency failure building xorg-x11

[mmitchel at gcc dot gnu dot org]

------- Comment #7 from mmitchel at gcc dot gnu dot org  2005-11-19 02:16 -------
S390 is not release critical.


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mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1 Regression] fatal error: internal consistency failure building xorg-x11

[rguenth at gcc dot gnu dot org]

------- Comment #8 from rguenth at gcc dot gnu dot org  2005-11-19 10:12 -------
Bootstrapped and regtested on s390-linux-gnu for all default languages.  We
already branched, so I leave it to you comitting the patch.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1/4.2 Regression] fatal error: internal consistency failure building xorg-x11

[ian at gcc dot gnu dot org]

------- Comment #9 from ian at gcc dot gnu dot org  2005-11-21 05:41 -------
Subject: Bug 24883

Author: ian
Date: Mon Nov 21 05:41:36 2005
New Revision: 107279

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=107279
Log:
./:
        PR rtl-optimization/24883
        * combine.c (combinable_i3pat): When checking whether the
        destination of i3 is used in i3, consider paradoxical subregs.
testsuite/:
        PR rtl-optimization/24883
        * gcc.c-torture/compile/pr24883.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/compile/pr24883.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/combine.c
    trunk/gcc/testsuite/ChangeLog


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1/4.2 Regression] fatal error: internal consistency failure building xorg-x11

[ian at gcc dot gnu dot org]

------- Comment #10 from ian at gcc dot gnu dot org  2005-11-21 05:43 -------
Subject: Bug 24883

Author: ian
Date: Mon Nov 21 05:43:32 2005
New Revision: 107280

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=107280
Log:
./:
        PR rtl-optimization/24883
        * combine.c (combinable_i3pat): When checking whether the
        destination of i3 is used in i3, consider paradoxical subregs.
testsuite/:
        PR rtl-optimization/24883
        * gcc.c-torture/compile/pr24883.c: New test.

Added:
    branches/gcc-4_1-branch/gcc/testsuite/gcc.c-torture/compile/pr24883.c
Modified:
    branches/gcc-4_1-branch/gcc/ChangeLog
    branches/gcc-4_1-branch/gcc/combine.c
    branches/gcc-4_1-branch/gcc/testsuite/ChangeLog


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883

[Bug rtl-optimization/24883] [4.1/4.2 Regression] fatal error: internal consistency failure building xorg-x11

[ian at airs dot com]

------- Comment #11 from ian at airs dot com  2005-11-21 05:45 -------
Fixed on mainline and 4.1 branch.


-- 

ian at airs dot com changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24883