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Date: Wed, 28 Jul 2010 09:54:00 -0000
Subject: [Bug debug/45103]  New: DW_OP_reg* has too large valid range for noreturn funcs
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From: "jan dot kratochvil at redhat dot com" <gcc-bugzilla@gcc.gnu.org>
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Use -g -O2.

DW_OP_reg5 is there valid for each PC, despite there si a `call' and reg5 is
caller-saved register.  Its value therefore gets corrupted in the callee.

FAIL all these:
gcc (GCC) 4.6.0 20100724 (experimental)
gcc (GCC) 4.5.1 20100728 (prerelease)
gcc (GCC) 4.4.5 20100724 (prerelease)
gcc-4.4.4-10.fc13.x86_64
GNU gdb (GDB) 7.2.50.20100724-cvs

#0  breakat (q=0) at 1.c:7
#1  0x000000000040053b in f (a1=<value optimized out>, a2=2, a3=3, a4=4, a5=5,
a6=6, a7=7) at 2.c:6
#2  0x00000000004004fc in g (x=0) at 1.c:14
                             ^^^ x=10 here, it should be <value optimized out>
#3  0x000000000040051e in main () at 2.c:14

==> 1.c <==
#include <stdlib.h>

extern __attribute__((noreturn)) void f (long a1, long a2, long a3, long a4,
long a5, long a6, long a7);

__attribute__((noreturn)) void
breakat (long q)
{
  exit (0);
}

__attribute__((noinline)) void
g (long x)
{
  f (x, 2, 3, 4, 5, 6, 7);
}

==> 2.c <==
extern __attribute__((noreturn)) void breakat (long q);

__attribute__((noreturn)) void
f (long a1, long a2, long a3, long a4, long a5, long a6, long a7)
{
  breakat (0);
}

extern __attribute__((noinline)) void g (long x);

int
main (void)
{
  g (10);
  return 0;
}


-- 
           Summary: DW_OP_reg* has too large valid range for noreturn funcs
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jan dot kratochvil at redhat dot com
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45103