From e8206491f015e63752c9db55d1b887a69d45b6af Mon Sep 17 00:00:00 2001
From: Roger Sayle <roger@eyesopen.com>
Date: Tue, 28 Mar 2006 17:06:19 +0000
Subject: [PATCH] fold-const.c (fold_unary): Fold (T1)(~(T2)X) as ~(T1)X...

	* fold-const.c (fold_unary) <NOP_EXPR>: Fold (T1)(~(T2)X) as
	~(T1)X, when T1 and T2 are integer types of the same precision
	and (T2)X isn't an extension.

	* gcc.dg/fold-convnotconv-1.c: New test case.

From-SVN: r112455
---
 gcc/ChangeLog                             |  6 ++++++
 gcc/fold-const.c                          | 16 ++++++++++++++++
 gcc/testsuite/ChangeLog                   |  4 ++++
 gcc/testsuite/gcc.dg/fold-convnotconv-1.c | 17 +++++++++++++++++
 4 files changed, 43 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/fold-convnotconv-1.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 69f7f65f6fcb..64bbd152acf1 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2006-03-28  Roger Sayle  <roger@eyesopen.com>
+
+	* fold-const.c (fold_unary) <NOP_EXPR>: Fold (T1)(~(T2)X) as
+	~(T1)X, when T1 and T2 are integer types of the same precision
+	and (T2)X isn't an extension.
+
 2006-03-28  Jeff Law  <law@redhat.com>
 
 	PR tree-optimization/26796
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 1381184f115c..695dc5d35122 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -7074,6 +7074,22 @@ fold_unary (enum tree_code code, tree type, tree op0)
 			   TREE_OPERAND (arg0, 1));
 	}
 
+      /* Convert (T1)(~(T2)X) into ~(T1)X if T1 and T2 are integral types
+	 of the same precision, and X is a integer type not narrower than
+	 types T1 or T2, i.e. the cast (T2)X isn't an extension.  */
+      if (INTEGRAL_TYPE_P (type)
+	  && TREE_CODE (op0) == BIT_NOT_EXPR
+	  && INTEGRAL_TYPE_P (TREE_TYPE (op0))
+	  && (TREE_CODE (TREE_OPERAND (op0, 0)) == NOP_EXPR
+	      || TREE_CODE (TREE_OPERAND (op0, 0)) == CONVERT_EXPR)
+	  && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (op0)))
+	{
+	  tem = TREE_OPERAND (TREE_OPERAND (op0, 0), 0);
+	  if (INTEGRAL_TYPE_P (TREE_TYPE (tem))
+	      && TYPE_PRECISION (type) <= TYPE_PRECISION (TREE_TYPE (tem)))
+	    return fold_build1 (BIT_NOT_EXPR, type, fold_convert (type, tem));
+	}
+
       tem = fold_convert_const (code, type, arg0);
       return tem ? tem : NULL_TREE;
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c2383d247b5d..8443fdaded5c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+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>
 
 	PR fortran/26779
diff --git a/gcc/testsuite/gcc.dg/fold-convnotconv-1.c b/gcc/testsuite/gcc.dg/fold-convnotconv-1.c
new file mode 100644
index 000000000000..fc07903c5159
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/fold-convnotconv-1.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-original" } */
+
+int test1(int a)
+{
+  return ~(unsigned int)a;
+}
+
+unsigned int test2(unsigned int b)
+{
+  return ~(int)b;
+}
+
+/* { dg-final { scan-tree-dump-times "~a" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "~b" 1 "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */
+