fold-const.c (fold_binary): Fold (X & Y) ^ Y as the equivalent ~X & Y, and the symmetry related transformations.

	* fold-const.c (fold_binary) <BIT_XOR_EXPR>: Fold (X & Y) ^ Y as
	the equivalent ~X & Y, and the symmetry related transformations.
	(fold_binary) <BIT_AND_EXPR>: Similarly, fold (X ^ Y) & Y as 
	~X & Y, and symmetry related transforms.

	* gcc.dg/fold-andxor-1.c: New test case.
	* gcc.dg/fold-xorand-1.c: Likewise.

From-SVN: r112459

5 files changed, 148 insertions, 0 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 12d43d4..17f1e2e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2006-03-28  Roger Sayle  <roger@eyesopen.com>
+
+	* fold-const.c (fold_binary) <BIT_XOR_EXPR>: Fold (X & Y) ^ Y as
+	the equivalent ~X & Y, and the symmetry related transformations.
+	(fold_binary) <BIT_AND_EXPR>: Similarly, fold (X ^ Y) & Y as 
+	~X & Y, and symmetry related transforms.
+
 2006-03-28  Maxim Kuvyrkov  <mkuvyrkov@ispras.ru>
 
 	Revert my 2006-03-27 patches.
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 695dc5d..aa710b1 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -8803,6 +8803,45 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
 	return fold_build2 (EQ_EXPR, type, arg0,
 			    build_int_cst (TREE_TYPE (arg0), 0));
 
+      /* Fold (X & Y) ^ Y as ~X & Y.  */
+      if (TREE_CODE (arg0) == BIT_AND_EXPR
+	  && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
+	{
+	  tem = fold_convert (type, TREE_OPERAND (arg0, 0));
+	  return fold_build2 (BIT_AND_EXPR, type, 
+			      fold_build1 (BIT_NOT_EXPR, type, tem),
+			      fold_convert (type, arg1));
+	}
+      /* Fold (X & Y) ^ X as ~Y & X.  */
+      if (TREE_CODE (arg0) == BIT_AND_EXPR
+	  && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)
+	  && reorder_operands_p (TREE_OPERAND (arg0, 1), arg1))
+	{
+	  tem = fold_convert (type, TREE_OPERAND (arg0, 1));
+	  return fold_build2 (BIT_AND_EXPR, type,
+			      fold_build1 (BIT_NOT_EXPR, type, tem),
+			      fold_convert (type, arg1));
+	}
+      /* Fold X ^ (X & Y) as X & ~Y.  */
+      if (TREE_CODE (arg1) == BIT_AND_EXPR
+	  && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
+	{
+	  tem = fold_convert (type, TREE_OPERAND (arg1, 1));
+	  return fold_build2 (BIT_AND_EXPR, type,
+			      fold_convert (type, arg0),
+			      fold_build1 (BIT_NOT_EXPR, type, tem));
+	}
+      /* Fold X ^ (Y & X) as ~Y & X.  */
+      if (TREE_CODE (arg1) == BIT_AND_EXPR
+	  && operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0)
+	  && reorder_operands_p (arg0, TREE_OPERAND (arg1, 0)))
+	{
+	  tem = fold_convert (type, TREE_OPERAND (arg1, 0));
+	  return fold_build2 (BIT_AND_EXPR, type,
+			      fold_build1 (BIT_NOT_EXPR, type, tem),
+			      fold_convert (type, arg0));
+	}
+
       /* See if this can be simplified into a rotate first.  If that
 	 is unsuccessful continue in the association code.  */
       goto bit_rotate;
@@ -8877,6 +8916,45 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1)
 			      build_int_cst (TREE_TYPE (tem), 0));
 	}
 
+      /* Fold (X ^ Y) & Y as ~X & Y.  */
+      if (TREE_CODE (arg0) == BIT_XOR_EXPR
+	  && operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
+	{
+	  tem = fold_convert (type, TREE_OPERAND (arg0, 0));
+	  return fold_build2 (BIT_AND_EXPR, type, 
+			      fold_build1 (BIT_NOT_EXPR, type, tem),
+			      fold_convert (type, arg1));
+	}
+      /* Fold (X ^ Y) & X as ~Y & X.  */
+      if (TREE_CODE (arg0) == BIT_XOR_EXPR
+	  && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0)
+	  && reorder_operands_p (TREE_OPERAND (arg0, 1), arg1))
+	{
+	  tem = fold_convert (type, TREE_OPERAND (arg0, 1));
+	  return fold_build2 (BIT_AND_EXPR, type,
+			      fold_build1 (BIT_NOT_EXPR, type, tem),
+			      fold_convert (type, arg1));
+	}
+      /* Fold X & (X ^ Y) as X & ~Y.  */
+      if (TREE_CODE (arg1) == BIT_XOR_EXPR
+	  && operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
+	{
+	  tem = fold_convert (type, TREE_OPERAND (arg1, 1));
+	  return fold_build2 (BIT_AND_EXPR, type,
+			      fold_convert (type, arg0),
+			      fold_build1 (BIT_NOT_EXPR, type, tem));
+	}
+      /* Fold X & (Y ^ X) as ~Y & X.  */
+      if (TREE_CODE (arg1) == BIT_XOR_EXPR
+	  && operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0)
+	  && reorder_operands_p (arg0, TREE_OPERAND (arg1, 0)))
+	{
+	  tem = fold_convert (type, TREE_OPERAND (arg1, 0));
+	  return fold_build2 (BIT_AND_EXPR, type,
+			      fold_build1 (BIT_NOT_EXPR, type, tem),
+			      fold_convert (type, arg0));
+	}
+
       t1 = distribute_bit_expr (code, type, arg0, arg1);
       if (t1 != NULL_TREE)
 	return t1;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8443fda..91e2220 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2006-03-28  Roger Sayle  <roger@eyesopen.com>
 
+	* gcc.dg/fold-andxor-1.c: New test case.
+	* gcc.dg/fold-xorand-1.c: Likewise.
+
+2006-03-28  Roger Sayle  <roger@eyesopen.com>
+
 	* gcc.dg/fold-convnotconv-1.c: New test case.
 
 2006-03-28 Paul Thomas <pault@gcc.gnu.org>
diff --git a/gcc/testsuite/gcc.dg/fold-andxor-1.c b/gcc/testsuite/gcc.dg/fold-andxor-1.c
new file mode 100644
index 0000000..cc46577
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fold-andxor-1.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-original" } */
+
+int test1(int a, int b)
+{
+  return (a ^ b) & a;
+}
+
+int test2(int c, int d)
+{
+  return (c ^ d) & d;
+}
+
+int test3(int e, int f)
+{
+  return e & (e ^ f);
+}
+
+int test4(int g, int h)
+{
+  return g & (h ^ g);
+}
+
+/* { dg-final { scan-tree-dump-times "~b \& a" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "~c \& d" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "~f \& e" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "~h \& g" 1 "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */
+
diff --git a/gcc/testsuite/gcc.dg/fold-xorand-1.c b/gcc/testsuite/gcc.dg/fold-xorand-1.c
new file mode 100644
index 0000000..8d42654
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fold-xorand-1.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-original" } */
+
+int test1(int a, int b)
+{
+  return (a & b) ^ a;
+}
+
+int test2(int c, int d)
+{
+  return (c & d) ^ d;
+}
+
+int test3(int e, int f)
+{
+  return e ^ (e & f);
+}
+
+int test4(int g, int h)
+{
+  return g ^ (h & g);
+}
+
+/* { dg-final { scan-tree-dump-times "~b \& a" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "~c \& d" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "~f \& e" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "~h \& g" 1 "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */
+