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From: "tnfchris at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/113734] [14 regression] libarchive miscompiled
 (fails libarchive_test_read_format_rar5_extra_field_version test) since
 r14-8768-g85094e2aa6dba7
Date: Tue, 13 Feb 2024 04:33:18 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D113734

--- Comment #24 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
The case I thought would go wrong with the above fix is:

#include <string.h>
#include <stdlib.h>
#include <stdio.h>

#define N 306
#define NEEDLE 135

__attribute__ ((noipa, noinline))
int use(int x[N])
{
  printf("res=3D%d\n", x[NEEDLE]);
  return x[NEEDLE];
}

__attribute__ ((noipa, noinline))
int foo (int i, unsigned short parse_tables_n)
{
  int table[N];
  memset (table, -1, sizeof (table));

  parse_tables_n >>=3D 9;
  parse_tables_n +=3D 9;
  while (i < N && parse_tables_n--)
    table[i++] =3D 0;

  return use (table);
}

int main ()
{
  if (foo (0, 0xFFFF) !=3D 0)
    abort ();

  return 0;
}

---
but this seems fine because of the bias_for_lowest which I now understand t=
o be
there to account for this.

So starting a regtest for that patch.=