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combine.c (try_combine): Add code to try to merge a set of a two-word pseudo to a constant with a... 

* 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.

From-SVN: r30674
This commit is contained in:
Richard Kenner 1999-11-27 13:59:20 +00:00 committed by Richard Kenner
parent 1baa375fea
commit 667c1c2c84
2 changed files with 50 additions and 0 deletions
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4
gcc/ChangeLog
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@ -1,5 +1,9 @@
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.

46
gcc/combine.c
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@ -1563,6 +1563,52 @@ try_combine (i3, i2, i1)
}
}
/* 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)))