diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f525c95441a..7493d2313b2 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2011-08-02  Kai Tietz  <ktietz@redhat.com>
+
+	* gimple.c (canonicalize_cond_expr_cond): Handle cast from
+	boolean-type.
+	(ssa_forward_propagate_and_combine): Interprete result of
+	forward_propagate_comparison.
+	* gcc/gimple-fold.c (fold_gimple_assign): Add canonicalization for
+	boolean-typed operands for comparisons.
+
 2011-08-02  Georg-Johann Lay  <avr@gjlay.de>
 	
 	* config/avr/libgcc.S: Gather related function in the
diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index cc89b2fd4fb..cd988b9c1db 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -814,6 +814,47 @@ fold_gimple_assign (gimple_stmt_iterator *si)
 					     gimple_assign_rhs1 (stmt),
 					     gimple_assign_rhs2 (stmt));
 	}
+      /* Try to canonicalize for boolean-typed X the comparisons
+	 X == 0, X == 1, X != 0, and X != 1.  */
+      else if (gimple_assign_rhs_code (stmt) == EQ_EXPR
+               || gimple_assign_rhs_code (stmt) == NE_EXPR)
+        {
+	  tree lhs = gimple_assign_lhs (stmt);
+	  tree op1 = gimple_assign_rhs1 (stmt);
+	  tree op2 = gimple_assign_rhs2 (stmt);
+	  tree type = TREE_TYPE (op1);
+
+	  /* Check whether the comparison operands are of the same boolean
+	     type as the result type is.
+	     Check that second operand is an integer-constant with value
+	     one or zero.  */
+	  if (TREE_CODE (op2) == INTEGER_CST
+	      && (integer_zerop (op2) || integer_onep (op2))
+	      && useless_type_conversion_p (TREE_TYPE (lhs), type))
+	    {
+	      enum tree_code cmp_code = gimple_assign_rhs_code (stmt);
+	      bool is_logical_not = false;
+
+	      /* X == 0 and X != 1 is a logical-not.of X
+	         X == 1 and X != 0 is X  */
+	      if ((cmp_code == EQ_EXPR && integer_zerop (op2))
+	          || (cmp_code == NE_EXPR && integer_onep (op2)))
+	        is_logical_not = true;
+
+	      if (is_logical_not == false)
+	        result = op1;
+	      /* Only for one-bit precision typed X the transformation
+	         !X -> ~X is valied.  */
+	      else if (TYPE_PRECISION (type) == 1)
+		result = build1_loc (gimple_location (stmt), BIT_NOT_EXPR,
+				     type, op1);
+	      /* Otherwise we use !X -> X ^ 1.  */
+	      else
+	        result = build2_loc (gimple_location (stmt), BIT_XOR_EXPR,
+				     type, op1, build_int_cst (type, 1));
+	     
+	    }
+	}
 
       if (!result)
         result = fold_binary_loc (loc, subcode,
diff --git a/gcc/gimple.c b/gcc/gimple.c
index e3095d7e261..af23c6a3fc9 100644
--- a/gcc/gimple.c
+++ b/gcc/gimple.c
@@ -3160,7 +3160,9 @@ canonicalize_cond_expr_cond (tree t)
 {
   /* Strip conversions around boolean operations.  */
   if (CONVERT_EXPR_P (t)
-      && truth_value_p (TREE_CODE (TREE_OPERAND (t, 0))))
+      && (truth_value_p (TREE_CODE (TREE_OPERAND (t, 0)))
+          || TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0)))
+	     == BOOLEAN_TYPE))
     t = TREE_OPERAND (t, 0);
 
   /* For !x use x == 0.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4ff8a1010d4..103bf569b86 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2011-08-02  Kai Tietz  <ktietz@redhat.com>
+
+	* gcc.dg/tree-ssa/forwprop-15.c: New testcase.
+
 2011-08-01  Jason Merrill  <jason@redhat.com>
 
 	PR c++/49932
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/forwprop-15.c b/gcc/testsuite/gcc.dg/tree-ssa/forwprop-15.c
new file mode 100644
index 00000000000..43c63516774
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/forwprop-15.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-forwprop1" }  */
+
+_Bool
+foo (_Bool a, _Bool b, _Bool c
+{
+  _Bool r1 = a == 0 & b != 0;
+  _Bool r2 = b != 0 & c == 0;
+  return (r1 == 0 & r2 == 0);
+}
+
+/* { dg-final { scan-tree-dump-times " == " 0 "forwprop1" } } */
+/* { dg-final { scan-tree-dump-times " != " 0 "forwprop1" } } */
+/* { dg-final { cleanup-tree-dump "forwprop1" } } */
diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index 7cf420ff496..2a56b79a423 100644
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -468,7 +468,9 @@ forward_propagate_into_comparison (gimple_stmt_iterator *gsi)
   if (tmp)
     {
       gimple_assign_set_rhs_from_tree (gsi, tmp);
+      fold_stmt_inplace (stmt);
       update_stmt (stmt);
+
       if (TREE_CODE (rhs1) == SSA_NAME)
 	cfg_changed |= remove_prop_source_from_use (rhs1);
       if (TREE_CODE (rhs2) == SSA_NAME)
@@ -2407,7 +2409,8 @@ ssa_forward_propagate_and_combine (void)
 	    }
 	  else if (TREE_CODE_CLASS (code) == tcc_comparison)
 	    {
-	      forward_propagate_comparison (stmt);
+	      if (forward_propagate_comparison (stmt))
+	        cfg_changed = true;
 	      gsi_next (&gsi);
 	    }
 	  else