@@ -764,6 +764,20 @@ force_subreg (machine_mode outermode, rtx op,
return res;
}
+/* Try to return an rvalue expression for the OUTERMODE lowpart of OP,
+ which has mode INNERMODE. Allow OP to be forced into a new register
+ if necessary.
+
+ Return null on failure. */
+
+rtx
+force_lowpart_subreg (machine_mode outermode, rtx op,
+ machine_mode innermode)
+{
+ auto byte = subreg_lowpart_offset (outermode, innermode);
+ return force_subreg (outermode, op, innermode, byte);
+}
+
/* If X is a memory ref, copy its contents to a new temp reg and return
that reg. Otherwise, return X. */
@@ -43,6 +43,7 @@ extern rtx copy_to_suggested_reg (rtx, rtx, machine_mode);
extern rtx force_reg (machine_mode, rtx);
extern rtx force_subreg (machine_mode, rtx, machine_mode, poly_uint64);
+extern rtx force_lowpart_subreg (machine_mode, rtx, machine_mode);
/* Return given rtx, copied into a new temp reg if it was in memory. */
extern rtx force_not_mem (rtx);
@@ -3096,26 +3096,6 @@ expand_ffs (scalar_int_mode mode, rtx op0, rtx target)
return 0;
}
-/* Extract the OMODE lowpart from VAL, which has IMODE. Under certain
- conditions, VAL may already be a SUBREG against which we cannot generate
- a further SUBREG. In this case, we expect forcing the value into a
- register will work around the situation. */
-
-static rtx
-lowpart_subreg_maybe_copy (machine_mode omode, rtx val,
- machine_mode imode)
-{
- rtx ret;
- ret = lowpart_subreg (omode, val, imode);
- if (ret == NULL)
- {
- val = force_reg (imode, val);
- ret = lowpart_subreg (omode, val, imode);
- gcc_assert (ret != NULL);
- }
- return ret;
-}
-
/* Expand a floating point absolute value or negation operation via a
logical operation on the sign bit. */
@@ -3204,7 +3184,7 @@ expand_absneg_bit (enum rtx_code code, scalar_float_mode mode,
gen_lowpart (imode, op0),
immed_wide_int_const (mask, imode),
gen_lowpart (imode, target), 1, OPTAB_LIB_WIDEN);
- target = lowpart_subreg_maybe_copy (mode, temp, imode);
+ target = force_lowpart_subreg (mode, temp, imode);
set_dst_reg_note (get_last_insn (), REG_EQUAL,
gen_rtx_fmt_e (code, mode, copy_rtx (op0)),
@@ -4043,7 +4023,7 @@ expand_copysign_bit (scalar_float_mode mode, rtx op0, rtx op1, rtx target,
temp = expand_binop (imode, ior_optab, op0, op1,
gen_lowpart (imode, target), 1, OPTAB_LIB_WIDEN);
- target = lowpart_subreg_maybe_copy (mode, temp, imode);
+ target = force_lowpart_subreg (mode, temp, imode);
}
return target;