[Bug lto/43455] New: Compiler hang with -O2 -flto

[Bug lto/43455] New: Compiler hang with -O2 -flto

[marbacz at gmail dot com]

gcc -O2 -flto 1.c 2.c hangs.
-O1 or without -flto compiles and links just fine.

1.c:
struct bar {int x;};
extern struct bar foo(void);
int main()
{
        struct bar x=foo();
        return 0;
}

2.c:
typedef struct{int x;} bar;
bar foo (void)
{
        bar x;
        return x;
}

gcc -v:
Using built-in specs.
COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.5.0-alpha20100318/gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.5.0-alpha20100318/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with:
/var/tmp/portage/sys-devel/gcc-4.5.0_alpha20100318/work/gcc-4.5-20100318/configure
--prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.5.0-alpha20100318
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.5.0-alpha20100318/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.5.0-alpha20100318
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.5.0-alpha20100318/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.5.0-alpha20100318/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.5.0-alpha20100318/include/g++-v4
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --disable-altivec
--disable-fixed-point --with-ppl --with-cloog --enable-nls
--without-included-gettext --with-system-zlib --disable-checking
--disable-werror --enable-secureplt --enable-multilib --enable-libmudflap
--disable-libssp --enable-libgomp --enable-cld
--with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.5.0-alpha20100318/python
--disable-libgcj --enable-languages=c,c++ --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
--with-bugurl=http://bugs.gentoo.org/ --with-pkgversion='Gentoo
4.5.0_alpha20100318' --enable-lto
Thread model: posix
gcc version 4.5.0-alpha20100318 20100318 (experimental) (Gentoo
4.5.0_alpha20100318)


-- 
           Summary: Compiler hang with -O2 -flto
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: marbacz at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43455

[Bug lto/43455] Compiler hang with -O2 -flto

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2010-03-20 20:15 -------
Works for me on i?86-linux.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu dot
                   |                            |org
           Keywords|                            |lto


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43455

[Bug lto/43455] Compiler hang with -O2 -flto

[marbacz at gmail dot com]

------- Comment #2 from marbacz at gmail dot com  2010-03-20 22:25 -------
Passing -m32 make the hang disappear.

Below is slightly less reduced version of previous test case. It comes from gnu
bc.

It causes ICE. Uncommenting declarations changes ICE into hang. ICE doesn't go
away with -m32.

gcc -O2 -flto numeric.c eval.c 
===
In file included from eval.c:28:0,
                 from numeric.c:19,
                 from :0:
eval.c: In function 'dc_evalstr':
eval.c:30:10: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://bugs.gentoo.org/> for instructions.
lto-wrapper: /usr/x86_64-pc-linux-gnu/gcc-bin/4.5.0-alpha20100318/gcc returned
1 exit status
collect2: lto-wrapper returned 1 exit status
===

eval.c:
====
typedef enum {DC_UNINITIALIZED, DC_NUMBER, DC_STRING} dc_value_type;
typedef struct dc_number *dc_num;
typedef struct dc_string *dc_str;
typedef struct {
        dc_value_type dc_type;
        union { dc_num number; dc_str string; } v;
} dc_data;

const char *progname;

int main()
{
        return 0;
}
/*
int dc_func(int a, int b, int c);
void dc_push(dc_data);
dc_data dc_getnum(int a, int b, int c);
*/
static const char *input_str_string;

int
dc_evalstr (dc_data *string)
{
        const char *s;
        int peekc;
        switch (dc_func(0, 0, 0)){
        case 0:
                input_str_string = s - 1;
                dc_push(dc_getnum(0, 0, 0));
                s = input_str_string;
                if (peekc != -1)
                        --s;
                break;
        }
        return 0;
}
===

numeric.c 
===
typedef enum {DC_UNINITIALIZED, DC_NUMBER, DC_STRING} dc_value_type;
typedef struct bc_struct *dc_num;
typedef struct dc_string *dc_str;
typedef struct {
        dc_value_type dc_type;
        union {
                dc_num number;
                dc_str string;
        } v;
} dc_data;

dc_data dc_getnum(int input, int ibase, int readahead)
{
        dc_data x;
        return x;
}

int dc_func(int a, int b, int c){return 0;}
void dc_push(dc_data a){}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43455

[Bug lto/43455] ICE in fold_convert_loc, at fold-const.c:2670 with -O2 -flto

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2010-03-22 10:30 -------
I get on x86_64-linux

> ./xgcc -B. -flto t1.c t2.c -O2
In file included from t2.c:2:0,
                 from t1.c:2,
                 from :0:
t1.c: In function 'main':
t1.c:5:22: internal compiler error: in fold_convert_loc, at fold-const.c:2792
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
lto-wrapper: ././xgcc returned 1 exit status
collect2: lto-wrapper returned 1 exit status

same with the less reduced testcase on x86_64 and i?86 linux.

Thanks for the report.


This is because we do not merge

  struct bar {int x;};

and

  typedef struct{int x;} bar;

but we expect to be able to convert them into each other during inlining:

#2  0x0000000000c120ac in declare_return_variable (id=0x7fffffffd9d0, 
    return_slot=0x0, modify_dest=0x7ffff5af03c0)
    at /space/rguenther/src/svn/trunk/gcc/tree-inline.c:2690
2690        use = fold_convert (caller_type, var);
(gdb) l
2685
2686      /* Build the use expr.  If the return type of the function was
2687         promoted, convert it back to the expected type.  */
2688      use = var;
2689      if (!useless_type_conversion_p (caller_type, TREE_TYPE (var)))
2690        use = fold_convert (caller_type, var);


This is really invalid C as bar is re-declared in an incompatible way
(which you'd see if you combine both TUs).

Now, we shouldn't ICE here anyway and LTO should be forgiving to this
kind of errors.

The following fixes the symptoms.

Index: gcc/tree-inline.c
===================================================================
--- gcc/tree-inline.c   (revision 157619)
+++ gcc/tree-inline.c   (working copy)
@@ -2687,7 +2687,12 @@ declare_return_variable (copy_body_data
      promoted, convert it back to the expected type.  */
   use = var;
   if (!useless_type_conversion_p (caller_type, TREE_TYPE (var)))
-    use = fold_convert (caller_type, var);
+    {
+      if (fold_convertible_p (caller_type, var))
+       use = fold_convert (caller_type, var);
+      else
+       use = fold_build1 (VIEW_CONVERT_EXPR, caller_type, var);
+    }

   STRIP_USELESS_TYPE_CONVERSION (use);


-- 

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         |2010-03-22 10:30:26
               date|                            |
            Summary|Compiler hang with -O2 -flto|ICE in fold_convert_loc, at
                   |                            |fold-const.c:2670 with -O2 -
                   |                            |flto


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43455

[Bug lto/43455] ICE in fold_convert_loc, at fold-const.c:2670 with -O2 -flto

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |rguenth at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2010-03-22 10:30:26         |2010-03-22 10:30:41
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43455

[Bug lto/43455] ICE in fold_convert_loc, at fold-const.c:2670 with -O2 -flto

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2010-04-23 13:39 -------
I am testing a patch to tree_can_inline_p instead.  That doesn't work with
WPA as we do not have the call_stmt available there - Honza, any idea where
to re-apply the check?


-- 

rguenth at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43455

[Bug lto/43455] ICE in fold_convert_loc, at fold-const.c:2670 with -O2 -flto

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2010-04-23 15:18 -------
Subject: Bug 43455

Author: rguenth
Date: Fri Apr 23 15:18:24 2010
New Revision: 158669

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=158669
Log:
2010-04-23  Richard Guenther  <rguenther@suse.de>

        PR lto/43455
        * tree-inline.c (tree_can_inline_p): Also check compatibility
        of return types.

        * gcc.dg/lto/20100423-1_0.c: New testcase.
        * gcc.dg/lto/20100423-1_1.c: Likewise.

Added:
    trunk/gcc/testsuite/gcc.dg/lto/20100423-1_0.c
    trunk/gcc/testsuite/gcc.dg/lto/20100423-1_1.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-inline.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43455

[Bug lto/43455] ICE in fold_convert_loc, at fold-const.c:2670 with -O2 -flto

[rguenth at gcc dot gnu dot org]

------- Comment #5 from rguenth at gcc dot gnu dot org  2010-04-23 15:18 -------
Fixed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to fail|                            |4.5.0
         Resolution|                            |FIXED
   Target Milestone|---                         |4.6.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43455

[Bug lto/43455] ICE in fold_convert_loc, at fold-const.c:2670 with -O2 -flto

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.6.0                       |4.5.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43455

[Bug lto/43455] ICE in fold_convert_loc, at fold-const.c:2670 with -O2 -flto

[rguenth at gcc dot gnu dot org]

------- Comment #7 from rguenth at gcc dot gnu dot org  2010-05-19 13:16 -------
Subject: Bug 43455

Author: rguenth
Date: Wed May 19 13:14:37 2010
New Revision: 159564

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=159564
Log:
2010-05-19  Richard Guenther  <rguenther@suse.de>

        Backport from mainline:
        2010-04-26  Richard Guenther  <rguenther@suse.de>

        PR lto/43455
        * tree-inline.c (tree_can_inline_p): Also check compatibility
        of return types.

        * gcc.dg/lto/20100423-1_0.c: New testcase.
        * gcc.dg/lto/20100423-1_1.c: Likewise.

        2010-04-23  Richard Guenther  <rguenther@suse.de>

        PR lto/42653
        * tree.c (free_lang_data_in_decl): Do not reset DECL_CONTEXT
        of FUNCTION_DECLs.

        * g++.dg/lto/20100423-1_0.C: New testcase.

        2010-04-26  Richard Guenther  <rguenther@suse.de>

        PR lto/42425
        * tree.c (free_lang_data_in_type): Do not free TYPE_CONTEXT
        if emitting debug information and it is either a function
        or a namespace decl.

        * g++.dg/lto/20100423-2_0.C: New testcase.

        2010-04-26  Richard Guenther  <rguenther@suse.de>

        PR lto/43080
        * gimple.c (gimple_decl_printable_name): Deal gracefully
        with a NULL DECL_NAME.

        * g++.dg/lto/20100423-3_0.C: New testcase.

        2010-04-30  Richard Guenther  <rguenther@suse.de>

        PR lto/43946
        * passes.c (init_optimization_passes): Move pass_ipa_free_lang_data
        first after all lowering passes.

        * gcc.dg/lto/20100430-1_0.c: New testcase.

Added:
    branches/gcc-4_5-branch/gcc/testsuite/g++.dg/lto/20100423-1_0.C
    branches/gcc-4_5-branch/gcc/testsuite/g++.dg/lto/20100423-2_0.C
    branches/gcc-4_5-branch/gcc/testsuite/g++.dg/lto/20100423-3_0.C
    branches/gcc-4_5-branch/gcc/testsuite/gcc.dg/lto/20100423-1_0.c
    branches/gcc-4_5-branch/gcc/testsuite/gcc.dg/lto/20100423-1_1.c
    branches/gcc-4_5-branch/gcc/testsuite/gcc.dg/lto/20100430-1_0.c
Modified:
    branches/gcc-4_5-branch/gcc/ChangeLog
    branches/gcc-4_5-branch/gcc/gimple.c
    branches/gcc-4_5-branch/gcc/passes.c
    branches/gcc-4_5-branch/gcc/testsuite/ChangeLog
    branches/gcc-4_5-branch/gcc/tree-inline.c
    branches/gcc-4_5-branch/gcc/tree.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43455