[Bug tree-optimization/65215] New: [5 Regression] Bswap load miscompilation

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65215

            Bug ID: 65215
           Summary: [5 Regression] Bswap load miscompilation
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: jakub at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org

Starting with r210843, following testcase is miscompiled on big-endian e.g. at
-O2:
static inline unsigned int
foo (unsigned int x)
{
  return (x >> 24) | ((x >> 8) & 0xFF00) | ((x << 8) & 0xFF0000) | (x << 24);
}

__attribute__((noinline, noclone)) unsigned int
bar (unsigned long *x)
{
  return foo (*x);
}

int
main ()
{
  unsigned long l = foo (0xdeadbeefU) | 0xfeedbea800000000ULL;
  if (bar (&l) != 0xdeadbeefU)
    __builtin_abort ();
  return 0;
}