How to debug sigfpe when divide-by-zero doesn't occur

Question

I'm trying to compile ruby with O0 -ggdb3 on sw64---- a alpha-like arch and met a weird SIGFPE error:

(gdb) bt 
#0  0x000002000544463c in __divlu ()
   from /lib/libc.so.6.1
#1  0x0000020001fe6808 in distance_multiply (
    d=18446744073709551615, m=1) at regcomp.c:109
#2  0x0000020001ff5a44 in optimize_node_left (
    node=0x121f43be0, opt=0x2000db31480,
    env=0x2000db31678) at regcomp.c:5247
#3  0x0000020001ff4b6c in optimize_node_left (
    node=0x122387f60, opt=0x2000db317c0,
    env=0x2000db319b8) at regcomp.c:4982
#4  0x0000020001ff62c4 in set_optimize_info_from_tree (node=0x122387f60, reg=0x12216df60,
    scan_env=0x2000db31a20) at regcomp.c:5417
#5  0x0000020001ff6d64 in onig_compile_ruby (
    reg=0x12216df60,
    pattern=0x121c021e0 "\\A([^:\\s]*)(?:::([^:\\s]*))?\\s*=(.*)\\z", pattern_end=0x121c02205 "",
    einfo=0x2000db31bc0,
    sourcefile=0x12109eea0 "-", sourceline=90)
    at regcomp.c:5854
#6  0x0000020001fd9ef4 in onig_new_with_source (
    reg=0x2000db31bd8,
    pattern=0x121c021e0 "\\A([^:\\s]*)(?:::([^:\\s]*))?\\s*=(.*)\\z", pattern_end=0x121c02205 "",
    option=0, enc=0x12108c840,
    syntax=0x2000213fef8 <OnigSyntaxRuby>,
    einfo=0x2000db31bc0,
    sourcefile=0x12109eea0 "-", sourceline=90)
    at re.c:842
#7  0x0000020001fd9fe8 in make_regexp (
    s=0x121c021e0 "\\A([^:\\s]*)(?:::([^:\\s]*))?\\s*=(.*)\\z", len=37, enc=0x12108c840, flags=0,
    err=0x2000db31d20 "",
<tinue, or q <return> to quit---

IIUC, the backtrace from gdb tells me that the frame 1 distance_multiply is the root cause of sigfpe.

Below is the definition of distance_multiply

static OnigDistance
distance_multiply(OnigDistance d, int m)
{
  if (m == 0) return 0;

  if (d < ONIG_INFINITE_DISTANCE / m)
    return d * m;
  else
    return ONIG_INFINITE_DISTANCE;
}

As you can see, if m is zero, it will return directly, so devided-by-zero sigfpe will never occur. I have also tried to dump the value of d and m with the help of printf:

static OnigDistance
distance_multiply(OnigDistance d, int m)
{
    fprintf(stderr, "\n\nd = %zu, m = %d, ONIG_INFINITE_DISTANCE = %d    ", d, m, ONIG_INFINITE_DISTA\
NCE );
  if (m == 0)
  {
    fprintf(stderr, "m == 0, should return\n");
          return 0;
  }

  if (d < ONIG_INFINITE_DISTANCE / m)
  {

    fprintf(stderr, "d < ONIG_INFINITE_DISTANCE / m\n");
    return d * m;
  }
  else
  {
    fprintf(stderr, "else\n");
    return ONIG_INFINITE_DISTANCE;
  }
}

output:

#+BEGIN_SRC
d = 1, m = 0, ONIG_INFINITE_DISTANCE = -1    m == 0, should return


d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1    d < ONIG_INFINITE_DISTANCE / m
 22% [198/871]  ext/psych/lib/psych.rb

d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1
Thread 1 "ruby2.5" received signal SIGFPE, Arithmetic exception.
0x000002000209263c in __divlu () from /lib/libc.so.6.1
#+END_SRC

#+BEGIN_SRC
d = 1, m = 0, ONIG_INFINITE_DISTANCE = -1    m == 0, should return


d = 1, m = 2, ONIG_INFINITE_DISTANCE = -1    d < ONIG_INFINITE_DISTANCE / m
 43% [378/871]  lib/net/http.rb

d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1
Thread 1 "ruby2.5" received signal SIGFPE, Arithmetic exception.
0x0000020004bbc63c in __divlu () from /lib/libc.so.6.1
#+END_SRC

#+BEGIN_SRC
d = 1, m = 0, ONIG_INFINITE_DISTANCE = -1    m == 0, should return


d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1    d < ONIG_INFINITE_DISTANCE / m
 22% [198/871]  ext/psych/lib/psych.rb

d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1
Thread 1 "ruby2.5" received signal SIGFPE, Arithmetic exception.
0x000002000d9f063c in __divlu () from /lib/libc.so.6.1
#+END_SRC

#+BEGIN_SRC
d = 1, m = 0, ONIG_INFINITE_DISTANCE = -1    m == 0, should return


d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1    d < ONIG_INFINITE_DISTANCE / m
 22% [198/871]  ext/psych/lib/psych.rb

d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1
Thread 1 "ruby2.5" received signal SIGFPE, Arithmetic exception.
0x0000020001abc63c in __divlu () from /lib/libc.so.6.1
#+END_SRC

#+BEGIN_SRC
d = 1, m = 0, ONIG_INFINITE_DISTANCE = -1    m == 0, should return


d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1    d < ONIG_INFINITE_DISTANCE / m
 22% [198/871]  ext/psych/lib/psych.rb

d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1
Thread 1 "ruby2.5" received signal SIGFPE, Arithmetic exception.
0x0000020005ce263c in __divlu () from /lib/libc.so.6.1
#+END_SRC

#+BEGIN_SRC
d = 23, m = 1, ONIG_INFINITE_DISTANCE = -1    d < ONIG_INFINITE_DISTANCE / m


d = 24, m = 1, ONIG_INFINITE_DISTANCE = -1    d < ONIG_INFINITE_DISTANCE / m


d = 1, m = 0, ONIG_INFINITE_DISTANCE = -1    m == 0, should return
 37% [329/871]  lib/getoptlong.rb

d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1
Thread 1 "ruby2.5" received signal SIGFPE, Arithmetic exception.
0x0000020000ba863c in __divlu () from /lib/libc.so.6.1
(gdb)
#+END_SRC

From the log, we can see that the last log is always:

d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1

and d < ONIG_INFINITE_DISTANCE / m part is not printed because it has trapped into sigfpe already. What's strange is that some previous logs also printed d = 1, m = 1, ONIG_INFINITE_DISTANCE = -1, which means when d = 1 and m = 1, sigfpe doesn't occur in those cases.

What may happend? I have no ideas any more. Can disassembly help here?

EDIT:

Sorry for the lack of macro definitions:

#define ONIG_INFINITE_DISTANCE  ~((OnigDistance )0)
typedef size_t         OnigDistance;