This seems to work, with a suitable extendhipsi2 pattern for m32c:
Index: expr.c
===================================================================
--- expr.c (revision 140759)
+++ expr.c (working copy)
@@ -8455,12 +8459,34 @@ expand_expr_real_1 (tree exp, rtx target
if (modifier != EXPAND_SUM && modifier != EXPAND_INITIALIZER)
op0 = force_operand (op0, target);
return REDUCE_BIT_FIELD (op0);
}
}
+ if (code == POINTER_PLUS_EXPR
+ || TYPE_PRECISION (TREE_OPERAND (exp, 1)) < TYPE_PRECISION
(TREE_OPERAND (exp, 0)))
+ {
+ rtx reg;
+ enum machine_mode imode, omode;
+
+ expand_operands (TREE_OPERAND (exp, 0), TREE_OPERAND (exp, 1),
+ subtarget, &op0, &op1, 0);
+
+ if (op0 == const0_rtx)
+ return op1;
+ if (op1 == const0_rtx)
+ return op0;
+
+ imode = GET_MODE (op1);
+ omode = GET_MODE (op0);
+ reg = gen_reg_rtx (omode);
+ emit_move_insn (reg, gen_rtx_fmt_e (SIGN_EXTEND, omode, op1));
+ op1 = reg;
+ goto binop2;
+ }
+
/* No sense saving up arithmetic to be done
if it's all in the wrong mode to form part of an address.
And force_operand won't know whether to sign-extend or
zero-extend. */
if ((modifier != EXPAND_SUM && modifier != EXPAND_INITIALIZER)
|| mode != ptr_mode)
