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combine.c (combine_simplify_rtx): Use gen_unary to distribute the NOT for De Morgan's rule.

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* combine.c (combine_simplify_rtx): Use gen_unary to distribute
        the NOT for De Morgan's rule.
        * simplify-rtx.c (simplify_unary_operation): Simplify a BImode NOT
        of a comparison to the reverse comparison.

From-SVN: r36506
This commit is contained in:
Richard Henderson 2000-09-18 11:24:32 -07:00 • committed by Richard Henderson
parent b4927ead98
commit 5bd60ce6de
3 changed files with 27 additions and 15 deletions
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5
gcc/ChangeLog
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@ -1,5 +1,10 @@
2000-09-18 Richard Henderson <rth@cygnus.com>
* combine.c (combine_simplify_rtx): Use gen_unary to distribute
the NOT for De Morgan's rule.
* simplify-rtx.c (simplify_unary_operation): Simplify a BImode NOT
of a comparison to the reverse comparison.
* combine.c (try_combine): Allow split to create a single insn.
* machmode.def: Add BImode. Add a column for bitsize.

20
gcc/combine.c
View file

@ -3933,21 +3933,17 @@ combine_simplify_rtx (x, op0_mode, last, in_dest)
if (GET_CODE (XEXP (x, 0)) == IOR || GET_CODE (XEXP (x, 0)) == AND)
{
rtx in1 = XEXP (XEXP (x, 0), 0), in2 = XEXP (XEXP (x, 0), 1);
enum machine_mode op_mode;
if (GET_CODE (in1) == NOT)
in1 = XEXP (in1, 0);
else
in1 = gen_rtx_combine (NOT, GET_MODE (in1), in1);
op_mode = GET_MODE (in1);
in1 = gen_unary (NOT, op_mode, op_mode, in1);
if (GET_CODE (in2) == NOT)
in2 = XEXP (in2, 0);
else if (GET_CODE (in2) == CONST_INT
&& GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT)
in2 = GEN_INT (GET_MODE_MASK (mode) & ~INTVAL (in2));
else
in2 = gen_rtx_combine (NOT, GET_MODE (in2), in2);
op_mode = GET_MODE (in2);
if (op_mode == VOIDmode)
op_mode = mode;
in2 = gen_unary (NOT, op_mode, op_mode, in2);
if (GET_CODE (in2) == NOT)
if (GET_CODE (in2) == NOT && GET_CODE (in1) != NOT)
{
rtx tem = in2;
in2 = in1; in1 = tem;

17
gcc/simplify-rtx.c
View file

@ -583,10 +583,21 @@ simplify_unary_operation (code, mode, op, op_mode)
aren't constant. */
switch (code)
{
case NEG:
case NOT:
/* (not (not X)) == X, similarly for NEG. */
if (GET_CODE (op) == code)
/* (not (not X)) == X. */
if (GET_CODE (op) == NOT)
return XEXP (op, 0);
/* (not (eq X Y)) == (ne X Y), etc. */
if (mode == BImode && GET_RTX_CLASS (GET_CODE (op)) == '<'
&& can_reverse_comparison_p (op, NULL_RTX))
return gen_rtx_fmt_ee (reverse_condition (GET_CODE (op)),
op_mode, XEXP (op, 0), XEXP (op, 1));
break;
case NEG:
/* (neg (neg X)) == X. */
if (GET_CODE (op) == NEG)
return XEXP (op, 0);
break;