Sat Nov 27 08:38:26 1999 Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
+ * combine.c (try_combine): Add code to try to merge a set of a
+ two-word pseudo to a constant with a setting of one of those words
+ to a constant.
+
* fold-const.c (negate_expr, associate_trees, extract_muldiv): New.
(split_tree): Completely rework to make more general.
(make_range, fold): Call negate_expr.
}
}
+ /* If I2 is setting a double-word pseudo to a constant and I3 is setting
+ one of those words to another constant, merge them by making a new
+ constant. */
+ if (i1 == 0
+ && (temp = single_set (i2)) != 0
+ && (GET_CODE (SET_SRC (temp)) == CONST_INT
+ || GET_CODE (SET_SRC (temp)) == CONST_DOUBLE)
+ && GET_CODE (SET_DEST (temp)) == REG
+ && GET_MODE_CLASS (GET_MODE (SET_DEST (temp))) == MODE_INT
+ && GET_MODE_SIZE (GET_MODE (SET_DEST (temp))) == 2 * UNITS_PER_WORD
+ && GET_CODE (PATTERN (i3)) == SET
+ && GET_CODE (SET_DEST (PATTERN (i3))) == SUBREG
+ && SUBREG_REG (SET_DEST (PATTERN (i3))) == SET_DEST (temp)
+ && GET_MODE_CLASS (GET_MODE (SET_DEST (PATTERN (i3)))) == MODE_INT
+ && GET_MODE_SIZE (GET_MODE (SET_DEST (PATTERN (i3)))) == UNITS_PER_WORD
+ && GET_CODE (SET_SRC (PATTERN (i3))) == CONST_INT)
+ {
+ HOST_WIDE_INT lo, hi;
+
+ if (GET_CODE (SET_SRC (temp)) == CONST_INT)
+ lo = INTVAL (SET_SRC (temp)), hi = lo < 0 ? -1 : 0;
+ else
+ {
+ lo = CONST_DOUBLE_LOW (SET_SRC (temp));
+ hi = CONST_DOUBLE_HIGH (SET_SRC (temp));
+ }
+
+ if (subreg_lowpart_p (SET_DEST (PATTERN (i3))))
+ lo = INTVAL (SET_SRC (PATTERN (i3)));
+ else
+ hi = INTVAL (SET_SRC (PATTERN (i3)));
+
+ combine_merges++;
+ subst_insn = i3;
+ subst_low_cuid = INSN_CUID (i2);
+ added_sets_2 = added_sets_1 = 0;
+ i2dest = SET_DEST (temp);
+
+ SUBST (SET_SRC (temp),
+ immed_double_const (lo, hi, GET_MODE (SET_DEST (temp))));
+
+ newpat = PATTERN (i2);
+ i3_subst_into_i2 = 1;
+ goto validate_replacement;
+ }
+
#ifndef HAVE_cc0
/* If we have no I1 and I2 looks like:
(parallel [(set (reg:CC X) (compare:CC OP (const_int 0)))