[Bug tree-optimization/42645] New: "-fcompare-debug failure" at -O1

[Bug tree-optimization/42645] New: "-fcompare-debug failure" at -O1

[zsojka at seznam dot cz]

Command line:
g++ -O1 -fcompare-debug -c testcase.cpp
-fno-web doesn't help

Tested revisions (x86_64):
r155680 - crash
r155662 - crash (x86)
r154886 - crash
r153685 - crash

Output:
$ /mnt/svn/gcc-trunk/binary-155680-lto/bin/g++ -O1 -fcompare-debug -c
testcase.cpp
g++: testcase.cpp: -fcompare-debug failure

Valgrind:
no errors reported


-- 
           Summary: "-fcompare-debug failure" at -O1
           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=42645

[Bug tree-optimization/42645] "-fcompare-debug failure" at -O1

[zsojka at seznam dot cz]

------- Comment #1 from zsojka at seznam dot cz  2010-01-07 13:12 -------
Created an attachment (id=19497)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19497&action=view)
reduced testcase


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42645

[Bug tree-optimization/42645] "-fcompare-debug failure" at -O1

[jakub at gcc dot gnu dot org]

------- Comment #2 from jakub at gcc dot gnu dot org  2010-01-11 10:31 -------
The problem here are different holes in SSA_NAMEs - with
-fvar-tracking-assignments most of the SSA_NAME_VERSION values are one larger
than without it.  -fcompare-debug dumps include these versions in some MEMs, so
it triggers the failure, on this testcase no actual code difference is present
though.  The difference shows up during early inlining,
#0  make_ssa_name_fn (fn=0x7ffff1e8a6c0, var=0x7ffff1e9ebe0, stmt=0x0) at
../../gcc/tree-ssanames.c:126
#1  0x0000000000e97142 in make_ssa_name (var=0x7ffff1e9ebe0, stmt=0x0) at
../../gcc/tree-flow-inline.h:1247
#2  0x0000000000e9741d in remap_ssa_name (name=0x7ffff1de2898,
id=0x7fffffffde90) at ../../gcc/tree-inline.c:202
#3  0x0000000000e9a9b7 in remap_gimple_op_r (tp=0x7ffff1ddf238,
walk_subtrees=0x7fffffffd6b0, data=0x7fffffffda50) at
../../gcc/tree-inline.c:738
#4  0x0000000000dc3988 in walk_tree_1 (tp=0x7ffff1ddf238, func=0xe9a936
<remap_gimple_op_r>, data=0x7fffffffda50, pset=0x0, lh=0)
    at ../../gcc/tree.c:9978
#5  0x0000000000ea13bb in copy_debug_stmt (stmt=0x7ffff1ddf200,
id=0x7fffffffde90) at ../../gcc/tree-inline.c:2163
#6  0x0000000000ea1441 in copy_debug_stmts (id=0x7fffffffde90) at
../../gcc/tree-inline.c:2192
creates a SSA_NAME which of course -g0 doesn't create.  The debug stmt is even
reset immediately afterwards.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42645

[Bug tree-optimization/42645] "-fcompare-debug failure" at -O1

[zsojka at seznam dot cz]

------- Comment #3 from zsojka at seznam dot cz  2010-01-11 10:45 -------
Created an attachment (id=19538)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19538&action=view)
different reduced testcase

$ /mnt/svn/gcc-trunk/binary-155777-lto/bin/g++ -O1 -fcompare-debug -c
testcase-min15-manual.ii
g++: testcase-min15-manual.ii: -fcompare-debug failure (length)

Testcases like these are often created by delta when reducing with grepping for
'-fcompare-debug failure'. The important part in both testcases seems to be "no
return statement in function returning non-void" with returned value stored to
a variable.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42645

[Bug tree-optimization/42645] "-fcompare-debug failure" at -O1

[jakub at gcc dot gnu dot org]

------- Comment #4 from jakub at gcc dot gnu dot org  2010-01-11 11:28 -------
Testing a fix.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jakub at gcc dot gnu dot org
                   |dot org                     |
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2010-01-11 11:28:30
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42645

[Bug tree-optimization/42645] "-fcompare-debug failure" at -O1

[jakub at gcc dot gnu dot org]

------- Comment #5 from jakub at gcc dot gnu dot org  2010-01-11 12:12 -------
Created an attachment (id=19539)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=19539&action=view)
gcc45-pr42645.patch

Fix I'm going to bootstrap/regtest.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42645

[Bug tree-optimization/42645] "-fcompare-debug failure" at -O1

[jakub at gcc dot gnu dot org]

------- Comment #6 from jakub at gcc dot gnu dot org  2010-01-12 09:43 -------
Subject: Bug 42645

Author: jakub
Date: Tue Jan 12 09:43:31 2010
New Revision: 155830

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=155830
Log:
        PR tree-optimization/42645
        * tree-inline.c (processing_debug_stmt): Move earlier.  Make static.
        (remap_ssa_name): If processing_debug_stmt and name wasn't found in
        decl_map, set processing_debug_stmt to -1 and return name without
        any remapping.

        * g++.dg/other/pr42645-1.C: New test.
        * g++.dg/other/pr42645-2.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/other/pr42645-1.C
    trunk/gcc/testsuite/g++.dg/other/pr42645-2.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-inline.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42645

[Bug tree-optimization/42645] "-fcompare-debug failure" at -O1

[jakub at gcc dot gnu dot org]

------- Comment #7 from jakub at gcc dot gnu dot org  2010-01-13 10:08 -------
Fixed.


-- 

jakub at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42645