From 5bd60ce6de2d4e0b0e7975c04772393b76b97909 Mon Sep 17 00:00:00 2001
From: Richard Henderson <rth@cygnus.com>
Date: Mon, 18 Sep 2000 11:24:32 -0700
Subject: [PATCH] combine.c (combine_simplify_rtx): Use gen_unary to distribute
 the NOT for De Morgan's rule.

        * 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
---
 gcc/ChangeLog      |  5 +++++
 gcc/combine.c      | 20 ++++++++------------
 gcc/simplify-rtx.c | 17 ++++++++++++++---
 3 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a4612dd21a4..2e1a280d33b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -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.
diff --git a/gcc/combine.c b/gcc/combine.c
index 07c7e6733f4..033bfac8d64 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -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;
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 1e130768eed..eb1ac584dbb 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -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;