[Bug target/54236] [SH] Improve addc and subc insn utilization

[olegendo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54236

--- Comment #3 from Oleg Endo <olegendo at gcc dot gnu.org> ---
Some more addc candidates I ran into:

int test00 (int a, int b, int c, int d)
{
  return (d & 1) + a + b;
}

-O2 -m4:
        mov     r7,r0
        and     #1,r0
        add     r4,r0
        rts
        add     r5,r0

better:
        shlr    r7      // T = r7 & 1
        addc    r4,r5
        rts
        mov     r5,r0



int test01 (int a, int b, int c, int d)
{
  return ((d >> 31) & 1) + a + b;
}

-O2 -m4:
        shll    r7
        movt    r0
        add     r4,r0
        rts
        add     r5,r0

better:
        shll    r7      // T = (r7 >> 31) & 1
        addc    r4,r5
        rts
        mov     r5,r0