[Bug tree-optimization/62238] New: ICE with LTO on valid code on x86_64-linux-gnu in verify_ssa (in 64-bit mode)

["su at cs dot ucdavis.edu" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62238

            Bug ID: 62238
           Summary: ICE with LTO on valid code on x86_64-linux-gnu in
                    verify_ssa (in 64-bit mode)
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu

The following code causes an ICE when compiled with the current gcc trunk (as
well as 4.9.x) with LTO on x86_64-linux-gnu in 64-bit mode (but not in 32-bit
mode).

It is a regression from 4.8.x.

$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-unknown-linux-gnu/5.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-trunk/configure --prefix=/usr/local/gcc-trunk
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 5.0.0 20140823 (experimental) [trunk revision 214394] (GCC) 
$ 
$ gcc-trunk -O0 -c fn1.c
$ gcc-trunk -O0 -c main.c
$ gcc-trunk -O3 *.o
$ ./a.out
$ 
$ gcc-4.8 -flto -O0 -c fn1.c
$ gcc-4.8 -flto -O0 -c main.c
$ gcc-4.8 -flto -O3 *.o
$ ./a.out
$ 
$ gcc-trunk -flto -O0 -c fn1.c
$ gcc-trunk -flto -O0 -c main.c
$ gcc-trunk -flto -O3 *.o
fn1.c: In function ‘fn1’:
fn1.c:4:1: error: missing definition
 fn1 (int p)
 ^
for SSA_NAME: _73 in statement:
_32 = (unsigned int) _73;
fn1.c:4:1: internal compiler error: verify_ssa failed
0xab6be1 verify_ssa(bool, bool)
    ../../gcc-trunk/gcc/tree-ssa.c:1055
0x830f4b execute_function_todo
    ../../gcc-trunk/gcc/passes.c:1758
0x831a23 execute_todo
    ../../gcc-trunk/gcc/passes.c:1808
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
lto-wrapper: fatal error: gcc-trunk returned 1 exit status
compilation terminated.
/usr/bin/ld: fatal error: lto-wrapper failed
collect2: error: ld returned 1 exit status
$ 
$ cat fn1.c
int a[4], b, c, d; 

int
fn1 (int p)
{
  for (; d; d++)
    {
      unsigned int h;
      for (h = 0; h < 3; h++)
    {
      if (a[c+c+h])
        {
          if (p)
        break;
          return 0;
        }
      b = 0;
    }
    }
  return 0;
}
$ cat main.c
extern int fn1 (int);

int
main ()
{
  fn1 (0);
  return 0;
}
$
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From: "d.g.gorbachev at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug lto/62239] New: [5 Regression] ICE: in execute_todo, at passes.c:1795 with LTO
Date: Sat, 23 Aug 2014 14:09:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idb239

            Bug ID: 62239
           Summary: [5 Regression] ICE: in execute_todo, at passes.c:1795
                    with LTO
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: d.g.gorbachev at gmail dot com

cat > foo.c
char *foo(unsigned n)
{
  char *s = __builtin_calloc(1, n);
  return __builtin___strcat_chk(s, " ", __builtin_object_size(s, 0));
}
^D
$ gcc -O -flto -shared foo.c
foo.c: In function 'foo':
foo.c:1:7: internal compiler error: in execute_todo, at passes.c:1795
 char *foo(unsigned n)
       ^
0x84e3f13 execute_todo
        ../../gcc-5/gcc/passes.c:1795
Please submit a full bug report,
[...]