From: Roger Sayle <roger@eyesopen.com>
Date: Sat, 1 Jun 2002 16:51:00 +0000 (+0000)
Subject: fold-const.c (fold_truthop): Transform "a || b" into "(a|b) != 0" and "!p && !q"... 
X-Git-Tag: releases/gcc-3.3.0~4636
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=01c58f2670a5f7858b8762e06cab0a68b98a684f;p=thirdparty%2Fgcc.git

fold-const.c (fold_truthop): Transform "a || b" into "(a|b) != 0" and "!p && !q" into "(p|q) == 0" under...


	* fold-const.c (fold_truthop): Transform "a || b" into "(a|b) != 0"
	and "!p && !q" into "(p|q) == 0" under suitable conditions.

From-SVN: r54148
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 753ea40e102f..0dd65f30b66a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2002-06-01  Roger Sayle  <roger@eyesopen.com>
+
+	* fold-const.c (fold_truthop): Transform "a || b" into "(a|b) != 0"
+	and "!p && !q" into "(p|q) == 0" under suitable conditions.
+
 2002-06-01  Andreas Jaeger  <aj@suse.de>
 
 	* cppexp.c (cpp_classify_number): Cast precission to int for
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 400285e5fec2..0998a93aa2e4 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -3506,7 +3506,29 @@ fold_truthop (code, truth_type, lhs, rhs)
       && ! FLOAT_TYPE_P (TREE_TYPE (rl_arg))
       && simple_operand_p (rl_arg)
       && simple_operand_p (rr_arg))
-    return build (code, truth_type, lhs, rhs);
+    {
+      /* Convert (a != 0) || (b != 0) into (a | b) != 0.  */
+      if (code == TRUTH_OR_EXPR
+	  && lcode == NE_EXPR && integer_zerop (lr_arg)
+	  && rcode == NE_EXPR && integer_zerop (rr_arg)
+	  && TREE_TYPE (ll_arg) == TREE_TYPE (rl_arg))
+	return build (NE_EXPR, truth_type,
+		      build (BIT_IOR_EXPR, TREE_TYPE (ll_arg),
+			     ll_arg, rl_arg),
+		      integer_zero_node);
+
+      /* Convert (a == 0) && (b == 0) into (a | b) == 0.  */
+      if (code == TRUTH_AND_EXPR
+	  && lcode == EQ_EXPR && integer_zerop (lr_arg)
+	  && rcode == EQ_EXPR && integer_zerop (rr_arg)
+	  && TREE_TYPE (ll_arg) == TREE_TYPE (rl_arg))
+	return build (EQ_EXPR, truth_type,
+		      build (BIT_IOR_EXPR, TREE_TYPE (ll_arg),
+			     ll_arg, rl_arg),
+		      integer_zero_node);
+
+      return build (code, truth_type, lhs, rhs);
+    }
 
   /* See if the comparisons can be merged.  Then get all the parameters for
      each side.  */