Re: [PATCH] Fix minor nits in gimple-ssa-sprintf.c (PR tree-optimization/78586)

[Martin Sebor]

So, let's use another testcase, -O2 -W -Wall -fno-tree-vrp -fno-tree-ccp
and again UB in it:
volatile bool e;
volatile int x;

int
main ()
{
  x = 123;
  *(char *)&e = x;
  bool f = e;
  x = __builtin_snprintf (0, 0, "%d", f);
}

This will store 1 into x, while without -fprintf-return-value it would store
3.

Great, that's what I was looking for.  I turned it into the following
test case.  Let me try to massage it into a compile-only test suitable
for the test suite and commit it later today.

volatile bool e;
volatile int x;

#define FMT "%d"
const char *fmt = FMT;

int
main ()
{
  x = 123;
  *(char *)&e = x;
  bool f = e;

  int n1 = __builtin_snprintf (0, 0, FMT, f);
  int n2 = __builtin_snprintf (0, 0, fmt, f);

  __builtin_printf ("%i == %i\n", n1, n2);
  if (n1 != n2)
    __builtin_abort ();
}

Martin