[Bug target/91188] strict_low_part operations do not work

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91188

--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
The patched gcc compiles to:

test_andb:
        movl    %edi, %eax      # 2     [c=4 l=2]  *movsi_internal/0
        andb    %sil, %al       # 9     [c=4 l=3]  *andqi_1_slp
        ret             # 23    [c=0 l=1]  simple_return_internal

The patch also handles memory:

--cut here--
struct S1
{
  unsigned char val;
  unsigned char pad1;
  unsigned short pad2;
};

unsigned char m;

struct S1
__attribute__((noinline))
test_andb (struct S1 a)
{
  a.val &= m;

  return a;
}
--cut here--

gcc -O2:

test_andb:
        movl    %edi, %eax      # 2     [c=4 l=2]  *movsi_internal/0
        andb    m(%rip), %al    # 7     [c=8 l=6]  *andqi_1_slp
        ret             # 20    [c=0 l=1]  simple_return_internal

and immediate operands:

--cut here--
struct S1
{
  unsigned char val;
  unsigned char pad1;
  unsigned short pad2;
};

struct S1
__attribute__((noinline))
test_andb (struct S1 a)
{
  a.val &= 0x2a;

  return a;
}
--cut here--

gcc -O2:

test_andb:
        movl    %edi, %eax      # 2     [c=4 l=2]  *movsi_internal/0
        andb    $42, %al        # 7     [c=4 l=2]  *andqi_1_slp
        ret             # 20    [c=0 l=1]  simple_return_internal