static void
find_flags_uses_in_insn (struct comparison *cmp, rtx_insn *insn)
{
df_ref use;
/* If we've already lost track of uses, don't bother collecting more. */
if (cmp->missing_uses)
return;
/* Find a USE of the flags register. */
FOR_EACH_INSN_USE (use, insn)
if (DF_REF_REGNO (use) == targetm.flags_regnum)
{
rtx x, *loc;
/* If this is an unusual use, quit. */
if (DF_REF_TYPE (use) != DF_REF_REG_USE)
goto fail;
/* If we've run out of slots to record uses, quit. */
if (cmp->n_uses == MAX_CMP_USE)
goto fail;
/* Unfortunately the location of the flags register, while present
in the reference structure, doesn't help. We need to find the
comparison code that is outer to the actual flags use. */
loc = DF_REF_LOC (use);
x = PATTERN (insn);
if (GET_CODE (x) == PARALLEL)
x = XVECEXP (x, 0, 0);
x = SET_SRC (x);
if (GET_CODE (x) == IF_THEN_ELSE)
x = XEXP (x, 0);
if (COMPARISON_P (x)
&& loc == &XEXP (x, 0)
&& XEXP (x, 1) == const0_rtx)
{
/* We've found a use of the flags that we understand. */
struct comparison_use *cuse = &cmp->uses[cmp->n_uses++];
cuse->insn = insn;
cuse->loc = loc;
cuse->code = GET_CODE (x);
}
else
goto fail;
}
return;
fail:
/* We failed to recognize this use of the flags register. */
cmp->missing_uses = true;
}
rtx
compare_from_rtx (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
enum machine_mode mode, rtx size)
{
rtx tem;
/* If one operand is constant, make it the second one. Only do this
if the other operand is not constant as well. */
if (swap_commutative_operands_p (op0, op1))
{
tem = op0;
op0 = op1;
op1 = tem;
code = swap_condition (code);
}
do_pending_stack_adjust ();
code = unsignedp ? unsigned_condition (code) : code;
tem = simplify_relational_operation (code, VOIDmode, mode, op0, op1);
if (tem)
{
if (CONSTANT_P (tem))
return tem;
if (COMPARISON_P (tem))
{
code = GET_CODE (tem);
op0 = XEXP (tem, 0);
op1 = XEXP (tem, 1);
mode = GET_MODE (op0);
unsignedp = (code == GTU || code == LTU
|| code == GEU || code == LEU);
}
}
emit_cmp_insn (op0, op1, code, size, mode, unsignedp);
#if HAVE_cc0
return gen_rtx_fmt_ee (code, VOIDmode, cc0_rtx, const0_rtx);
#else
return gen_rtx_fmt_ee (code, VOIDmode, op0, op1);
#endif
}
