[Bug tree-optimization/20612] New: ICE in verify_ssa for -ftree-loop-linear

[Bug tree-optimization/20612] New: ICE in verify_ssa for -ftree-loop-linear

[janis at gcc dot gnu dot org]

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The SPEC CPU2000 benchmark 171.swim fails to build on powerpc64-linux
using "-m32 -O2 -ftree-loop-linear" with current GCC mainline due to
an ICE in verify_ssa.  I'll attach a minimized test case that gets the
same error:
                                                                                
elm3b145% /opt/gcc-nightly/mline-20050322/bin/gfortran -O2 -ftree-loop-linear -c
bug.f
bug.f: In function ‘MAIN__’:
bug.f:7: error: Definition in block 9 does not dominate use in block 3
for SSA_NAME: lnivtmp.4_34in statement:
if (lletmp.6_32 <= lnivtmp.4_34) goto <L20>; else goto <L21>;
bug.f:7: internal compiler error: verify_ssa failed.
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.
                                                                                
The failure starts sometime between 2005-03-01 09:57 UTC and
2005-03-02 02 03:03 UTC; my regression hunt ran into a build failure
in that range but I'll try to continue it to identify the patch that
introduced the bug or exposed a latent bug.

-- 
           Summary: ICE in verify_ssa for -ftree-loop-linear
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: janis at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: powerpc-linux
  GCC host triplet: powerpc-linux
GCC target triplet: powerpc-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20612

[Bug tree-optimization/20612] ICE in verify_ssa for -ftree-loop-linear

[janis at gcc dot gnu dot org]

------- Additional Comments From janis at gcc dot gnu dot org  2005-03-24 00:27 -------
Created an attachment (id=8440)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8440&action=view)
minimized testcase


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20612

[Bug tree-optimization/20612] ICE in verify_ssa for -ftree-loop-linear

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-03-24 00:52 -------
There are only two patches during that time frame could have caused this:
+2005-03-01  Daniel Berlin <dberlin@dberlin.org>
+
+       * Makefile.in (tree-ssa-sink.o): New.


and:
+2005-03-01  Zdenek Dvorak  <dvorakz@suse.cz>
+
+       * cfgloop.c (flow_loop_entry_edges_find, flow_loop_exit_edges_find,
+       flow_loop_pre_header_scan, flow_loop_pre_header_find,

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20612

[Bug tree-optimization/20612] ICE in verify_ssa for -ftree-loop-linear

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-03-24 04:04 -------
And easy winner is:
+2005-03-01  Daniel Berlin <dberlin@dberlin.org>
+
+       * Makefile.in (tree-ssa-sink.o): New.

using -fno-tree-sink causes no ICE.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dberlin at gcc dot gnu dot
                   |                            |org, pinskia at gcc dot gnu
                   |                            |dot org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
           Keywords|                            |ice-on-valid-code
   Last reconfirmed|0000-00-00 00:00:00         |2005-03-24 04:04:27
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20612

[Bug tree-optimization/20612] ICE in verify_ssa for -ftree-loop-linear

[dberlin at gcc dot gnu dot org]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-03-24 04:19 -------
I know what's up

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |dberlin at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2005-03-24 04:04:27         |2005-03-24 04:19:13
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20612

[Bug tree-optimization/20612] ICE in verify_ssa for -ftree-loop-linear

[dberlin at gcc dot gnu dot org]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-03-24 04:21 -------
To add some more detail:

We sink the iv increment because it wasn't used in the old exit test.

However, the exit test we want to generate wants to use it, but because we sunk
it, it no longer dominates the right block.
The easy fix here is to take the iv var, increment it on our own (instead of
trying to use the pre-inc'ed version), and just let rednudancy elimination sort
the rest out :)

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |SUSPENDED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20612

[Bug tree-optimization/20612] ICE in verify_ssa for -ftree-loop-linear

[dberlin at gcc dot gnu dot org]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-03-24 04:32 -------
i accidently marked it suspended :(

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|SUSPENDED                   |ASSIGNED
   Last reconfirmed|2005-03-24 04:19:13         |2005-03-24 04:32:49
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20612

[Bug tree-optimization/20612] ICE in verify_ssa for -ftree-loop-linear

[janis at gcc dot gnu dot org]

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------- Additional Comments From janis at gcc dot gnu dot org  2005-03-24 18:51 -------
I tried the patch with a biarch powerpc64-linux compiler; sixtrack now
works with "-m32 -O2 -ftree-loop-linear" but the swim compile dies in a
new place:

/home/janis/tools/gcc-mline-20050323-20612/bin/gfortran -c -o swim.o
-m32 -O2 -ftree-loop-linear   swim.f
swim.f: In function ‘MAIN__’:
swim.f:46: internal compiler error: in get_loop_body, at cfgloop.c:819

This ought to be reproducible with a vanilla powerpc-linux cross compiler
but I haven't tried that and won't have time to play with this for a few
days.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20612

[Bug tree-optimization/20612] ICE in verify_ssa for -ftree-loop-linear

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-04-11 18:55 -------
Subject: Bug 20612

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	dberlin@gcc.gnu.org	2005-04-11 18:55:47

Modified files:
	gcc            : ChangeLog lambda-code.c 

Log message:
	2005-04-11  Daniel Berlin  <dberlin@dberlin.org>
	
	Fix PR tree-optimization/20612
	* lambda-code.c (lambda_loopnest_to_gcc_loopnest): Fix increment
	handling
	(perfect_nestify): preheaderbb is *not* part of loop of the
	old destination.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.8233&r2=2.8234
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/lambda-code.c.diff?cvsroot=gcc&r1=2.32&r2=2.33



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20612

[Bug tree-optimization/20612] ICE in verify_ssa for -ftree-loop-linear

[dberlin at gcc dot gnu dot org]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-04-11 19:13 -------
Fixed

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20612

[Bug tree-optimization/20612] ICE in verify_ssa for -ftree-loop-linear

[pinskia at gcc dot gnu dot org]

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20612