[Bug tree-optimization/93044] extra cast is not removed

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93044

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note this is the original testcase where I saw the issue (even without the
bit-field lowering pass; that I am working on):
#define N 100
#define M 1111
struct S { int a : 3; int b : 17; int c : 12; };
struct S A[N][M];

int __attribute__((noinline))
foo (void)
{
  int i = 0, j = 0;

  A[j][i].a = A[j][i].a*5;

  return 0;
}