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From: "mhillen at linux dot ibm.com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug rtl-optimization/92294] alias attribute generates incorrect code
Date: Thu, 19 Nov 2020 11:03:23 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D92294

--- Comment #7 from Marius Hillenbrand <mhillen at linux dot ibm.com> ---
A simpler example derived from alias-2.c reproduces this issue on aarch64,
ppc64, and s390x.=20

int a;
extern int b __attribute__ ((alias("a")));
int off;

int foo()
{
  /* make sure off is ahead of a and b in .bss, so that a has a non-negative
   * offset relative to the anchor. */
  return off;
}

main()
{
  b=3D1;
  a=3D2;
  if (b!=3D2)
   __builtin_abort ();
  return 0;
}

Note that gcc.c-torture/execute/alias-2.c did not reproduce this issue on
ppc64(le) for me. Removing the array indexing reduces the complexity of the=
 RTL
dumps somewhat.=