Comment 4 for bug 1899114

I think this still affects package GCC-10 on both focal and groovy. Specifically the second repro posted above still crashes GCC. I'm repeating it here for clarity:

```
a;
b() {
  int c, d;
  __sigsetjmp();
  for (; a;)
    for (; d;) {
      if (c)
        c = e();
      f();
    }
}

```

putting the repro into `/tmp/c.c` and running `gcc-10 -O3 -c /tmp/c.c` triggers the bug:

```
c.c:1:1: warning: data definition has no type or storage class
    1 | a;
      | ^
c.c:1:1: warning: type defaults to 'int' in declaration of 'a' [-Wimplicit-int]
c.c:2:1: warning: return type defaults to 'int' [-Wimplicit-int]
    2 | b() {
      | ^
c.c: In function 'b':
c.c:4:3: warning: implicit declaration of function '__sigsetjmp' [-Wimplicit-function-declaration]
    4 | __sigsetjmp();
      | ^~~~~~~~~~~
c.c:8:13: warning: implicit declaration of function 'e' [-Wimplicit-function-declaration]
    8 | c = e();
      | ^
c.c:9:7: warning: implicit declaration of function 'f' [-Wimplicit-function-declaration]
    9 | f();
      | ^

Unable to coalesce ssa_names 3 and 4 which are marked as MUST COALESCE.
c_3(ab) and c_4(ab)
during RTL pass: expand
c.c:2:1: internal compiler error: SSA corruption
    2 | b() {
      | ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-10/README.Bugs> for instructions.

```

I tried the same repro on hirsute today and cannot reproduce the error.