[Bug tree-optimization/42917] New: [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

[Bug tree-optimization/42917] New: [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

[zsojka at seznam dot cz]

Command line:
gcc -O1 -ftree-loop-linear -fcompare-debug -c testcase.c
(fails at all -O1, -O2 and -O3 levels)

Tested revisions:
r156367 - crash
r155833 - crash
r154830 - crash
r153685 - crash

Output:
$ /mnt/svn/gcc-trunk/binary-156367-lto/bin/gcc -O1 -ftree-loop-linear
testcase.c -fcompare-debug
gcc: testcase.c: -fcompare-debug failure (length)

There is actually different code generated with -g, the outer loop isn't
removed. 4.4.2 generates the same code for both cases.


-- 
           Summary: [4.5 Regression] "-fcompare-debug failure" with -ftree-
                    loop-linear
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        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=42917

[Bug tree-optimization/42917] [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

[zsojka at seznam dot cz]

------- Comment #1 from zsojka at seznam dot cz  2010-01-31 21:41 -------
Created an attachment (id=19767)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19767&action=view)
reduced testcase

Command line:
gcc -O1 -ftree-loop-linear -fcompare-debug -c pr42917.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42917

[Bug tree-optimization/42917] [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42917

[Bug tree-optimization/42917] [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42917

[Bug tree-optimization/42917] [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

[jakub at gcc dot gnu dot org]

------- Comment #2 from jakub at gcc dot gnu dot org  2010-02-17 13:56 -------
I guess lambda-code.c needs to be taught about debug stmts.
This is actually more important than usual -fcompare-debug differences, here
debug stmt actually prevent the optimization altogether.
Without -g the loops are perfectly nested (perfect_nest_p succeeds), without it
the debug stmt cause both perfect_nest_p and can_convert_to_perfect_nest to
fail.

I guess best would be to ignore debug stmts in these functions, and do
something about them in perfect_nestify and in lambda_loopnest_to_gcc_loopnest,
but am not sure it will actually possible.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42917

[Bug tree-optimization/42917] [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

[jakub at gcc dot gnu dot org]

------- Comment #3 from jakub at gcc dot gnu dot org  2010-02-19 12:35 -------
I've tried
--- gcc/lambda-code.c.jj 2009-11-25 16:47:37.000000000 +0100
+++ gcc/lambda-code.c 2010-02-17 15:00:40.000000000 +0100
@@ -1885,7 +1885,8 @@ not_interesting_stmt (gimple stmt)
      loop, we would have already failed the number of exits tests.  */
   if (gimple_code (stmt) == GIMPLE_LABEL
       || gimple_code (stmt) == GIMPLE_GOTO
-      || gimple_code (stmt) == GIMPLE_COND)
+      || gimple_code (stmt) == GIMPLE_COND
+      || is_gimple_debug (stmt))
     return true;
   return false;
 }
and while it is sufficient for this testcase, it is not sufficient say for
gfortran.dg/ltrans-7.f90 with
--target_board=unix/-fcompare-debug/-ftree-loop-linear and a bunch of other
testcases, that no longer die on -fcompare-debug failures, but with checking
ICEs.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42917

[Bug tree-optimization/42917] [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2010-02-22 12:41 -------
Confirmed.


-- 

rguenth 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         |2010-02-22 12:41:57
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42917

[Bug tree-optimization/42917] [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

[aldyh at gcc dot gnu dot org]

-- 

aldyh at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42917

[Bug tree-optimization/42917] [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

[aldyh at gcc dot gnu dot org]

------- Comment #5 from aldyh at gcc dot gnu dot org  2010-03-16 11:34 -------
Subject: Bug 42917

Author: aldyh
Date: Tue Mar 16 11:33:45 2010
New Revision: 157477

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=157477
Log:
        PR tree-optimization/42917
        * lambda-code.c (remove_iv): Skip debug statements.
        (lambda_loopnest_to_gcc_loopnest): Likewise.
        (not_interesting_stmt): Debug statements are not interesting.


Added:
    trunk/gcc/testsuite/gcc.dg/pr42917.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/lambda-code.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42917

[Bug tree-optimization/42917] [4.5 Regression] "-fcompare-debug failure" with -ftree-loop-linear

[aldyh at gcc dot gnu dot org]

------- Comment #6 from aldyh at gcc dot gnu dot org  2010-03-16 11:36 -------
Fixed here:
http://gcc.gnu.org/ml/gcc-patches/2010-03/msg00560.html


-- 

aldyh at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42917