------- Additional Comments From rmathew at gcc dot gnu dot org 2005-06-18
05:14 -------
(In reply to comment #2)
> Subject: Re: Divide_1 test case hangs
>
> > -2147483648
> > -2147483648
> > 0
> > 0
> > [...]
> >
> > Note that the values are totally off.
> >
> This looks somewhat familiar. Could you try testing with
> -fno-tree-vrp?
Doesn't help. In a weird twist, I actually get the correct
result if I use any optimisation level (-O{1,2,3})! (That,
BTW, explains why the corresponding -O3 testcase didn't fail.)
When I compile this testcase manually and run it (at -O0),
I get:
1219954614
-2147483648
1174405120
12019755
0
Aborted
Under the debugger:
----------------------------- 8< -----------------------------
(gdb) r
Starting program: /home/rmathew/src/tmp/a.out
[Thread debugging using libthread_db enabled]
[New Thread -1225922896 (LWP 28945)]
[New Thread -1226114128 (LWP 28948)]
Program received signal SIGFPE, Arithmetic exception.
[Switching to Thread -1225922896 (LWP 28945)]
0x08048bc4 in Divide_1.probe_1() ([EMAIL PROTECTED]) at Divide_1.java:11
11 int c = a/b;
Current language: auto; currently java
(gdb) l
6
7 void probe_1 ()
8 {
9 try {
10 int a = Integer.parseInt ("-80000000", 16);
11 int c = a/b;
12 System.out.println (c);
13 } catch (Exception _) {
14 System.out.println (_);
15 }
(gdb) c
Continuing.
1488390214
-2147483648
Program received signal SIGFPE, Arithmetic exception.
0x08048dd3 in Divide_1.probe_1() ([EMAIL PROTECTED]) at Divide_1.java:27
27 int c = a%b;
(gdb) l
22 System.out.println (_);
23 }
24
25 try {
26 int a = Integer.parseInt ("-80000000", 16);
27 int c = a%b;
28 System.out.println (c);
29 } catch (Exception _) {
30 System.out.println (_);
31 }
(gdb) c
Continuing.
1174405120
Program received signal SIGFPE, Arithmetic exception.
0x08048eed in Divide_1.probe_1() ([EMAIL PROTECTED]) at Divide_1.java:35
35 int c = a%b1;
(gdb) l
30 System.out.println (_);
31 }
32
33 try {
34 int a = Integer.parseInt ("-80000000", 16);
35 int c = a%b1;
36 System.out.println (c);
37 } catch (Exception _) {
38 System.out.println (_);
39 }
(gdb) c
Continuing.
12019899
0
Program received signal SIGFPE, Arithmetic exception.
0x0804912a in Divide_1.probe_1() ([EMAIL PROTECTED]) at Divide_1.java:52
52 int c = a/b;
(gdb) l
47 }
48
49 try {
50 int a = Integer.parseInt ("8000", 16);
51 int b = Integer.parseInt ("0", 16);
52 int c = a/b;
53 System.out.println (c);
54 } catch (Exception _) {
55 System.out.println (_);
56 }
(gdb) c
Continuing.
Program received signal SIGSEGV, Segmentation fault.
uw_frame_state_for (context=0xbfffe6b8, fs=0xbfffe5f8) at linux-unwind.h:125
125 if (*(unsigned short *)(pc+0) == 0xb858
(gdb) p pc
No symbol "pc" in current context.
(gdb) p context->ra
$1 = (void *) 0x62f
(gdb) p *context
$2 = {reg = {0xbffff01c, 0xbffff018, 0xbffff014, 0xbffff4b1, 0x0, 0xbffff008,
0xbffff004, 0xbffff000, 0xbffff4b5, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0}, cfa = 0xbffff4b9, ra = 0x62f, lsda = 0x0, bases = {tbase = 0x0,
dbase = 0x804bc18, func = 0x8048b86}, args_size = 0}
(gdb) bt
#0 uw_frame_state_for (context=0xbfffe6b8, fs=0xbfffe5f8)
at linux-unwind.h:125
#1 0xb7fe5632 in _Unwind_Backtrace (
trace=0xb765d920 <_Jv_StackTrace::UnwindTraceFn(_Unwind_Context*, void*)>,
trace_argument=0xbfffef30) at unwind.inc:293
#2 0xb765dac0 in _Jv_StackTrace::GetStackTrace ()
at /extra/src/gcc/gcc-20050618/libjava/stacktrace.cc:159
#3 0xb768e29c in java::lang::VMThrowable::fillInStackTrace ()
at /extra/src/gcc/gcc-20050618/libjava/java/lang/natVMThrowable.cc:33
#4 0xb7871a52 in java.lang.Throwable.fillInStackTrace() (this=0x4f858)
at Throwable.java:498
#5 0xb7867532 in java.lang.Throwable.Throwable(java.lang.String) (
this=0x4f858, message=0x62f) at Throwable.java:159
#6 0xb7869f53 in java.lang.Exception.Exception(java.lang.String) (this=0x62f,
s=0x62f) at Exception.java:77
#7 0xb7869fe3 in java.lang.RuntimeException.RuntimeException(java.lang.String)
(this=0x62f, s=0x62f) at RuntimeException.java:75
#8 0xb786c273 in
java.lang.ArithmeticException.ArithmeticException(java.lang.String) (this=0x62f,
s=0x62f) at ArithmeticException.java:74
#9 0xb7650cde in catch_fpe (_dummy=8)
at /extra/src/gcc/gcc-20050618/libjava/prims.cc:166
#10 <signal handler called>
#11 0x0804912c in Divide_1.probe_1() (this=0x1e0004af) at Divide_1.java:52
---Type <return> to continue, or q <return> to quit---
#12 0x0000062f in ?? ()
#13 0x1e0004af in ?? ()
#14 0x000804a6 in ?? ()
#15 0x940004af in ?? ()
#16 0x08b7d3fa in ?? ()
#17 0x6dbffff5 in ?? ()
#18 0x00b78755 in ?? ()
#19 0x00b7e202 in ?? ()
[...and so on for 733 frames after which GDB 6.3 barfs out.]
----------------------------- 8< -----------------------------
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22084
