[Bug target/63321] [SH] Unused T bit result of shll / shlr insns

[olegendo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63321

--- Comment #7 from Oleg Endo <olegendo at gcc dot gnu.org> ---
Another example:

unsigned int
count_trailing_nonzero_bits (unsigned int v, unsigned int c)
{
  c += v & 1;
  v >>= 1;
  c += v & 1;
  v >>= 1;
  c += v & 1;
  v >>= 1;
  c += v & 1;
  v >>= 1;
  c += v & 1;
  v >>= 1;
  c += v & 1;
  v >>= 1;
  c += v & 1;
  v >>= 1;
  c += v & 1;
  v >>= 1;
  return c;
}

ideally should compile to:
  mov   #0,r1
  shlr  r4
  movt  r0
  shlr  r4
  addc  r1,r0
  shlr  r4
  addc  r1,r0
  shlr  r4
  addc  r1,r0
  shlr  r4
  addc  r1,r0
  shlr  r4
  addc  r1,r0
  shlr  r4
  addc  r1,r0
  shlr  r4
  addc  r1,r0