2007-07-20 Richard Guenther <rguenther@suse.de>

	* tree-cfg.c (verify_expr): COND_EXPRs can have any
	integral typed condition.
	* tree-ssa.c (useless_type_conversion_p): Do not preserve
	booleanness.  Only preserve conversions from a non-base
	type to a base type, not in general between types with
	different TYPE_MIN_VALUE or TYPE_MAX_VALUE.
	* tree.def (COND_EXPR): Document that the condition
	can be of any integral type.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@126804 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 25 insertions, 18 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ba96d763d96..9dbaf38ac16 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2007-07-20  Richard Guenther  <rguenther@suse.de>
+
+	* tree-cfg.c (verify_expr): COND_EXPRs can have any
+	integral typed condition.
+	* tree-ssa.c (useless_type_conversion_p): Do not preserve
+	booleanness.  Only preserve conversions from a non-base
+	type to a base type, not in general between types with
+	different TYPE_MIN_VALUE or TYPE_MAX_VALUE.
+	* tree.def (COND_EXPR): Document that the condition
+	can be of any integral type.
+
 2007-07-20  Nigel Stephens  <nigel@mips.com>
 	    Richard Sandiford  <richard@codesourcery.com>
 
diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index 09fe7ebbe10..889e7d747d7 100644
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -3201,9 +3201,9 @@ verify_expr (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
 
     case COND_EXPR:
       x = COND_EXPR_COND (t);
-      if (TREE_CODE (TREE_TYPE (x)) != BOOLEAN_TYPE)
+      if (!INTEGRAL_TYPE_P (TREE_TYPE (x)))
 	{
-	  error ("non-boolean used in condition");
+	  error ("non-integral used in condition");
 	  return x;
 	}
       if (!is_gimple_condexpr (x))
diff --git a/gcc/tree-ssa.c b/gcc/tree-ssa.c
index db16f2315d0..858745e683a 100644
--- a/gcc/tree-ssa.c
+++ b/gcc/tree-ssa.c
@@ -940,23 +940,18 @@ useless_type_conversion_p (tree outer_type, tree inner_type)
 	  || TYPE_PRECISION (inner_type) != TYPE_PRECISION (outer_type))
 	return false;
 
-      /* Preserve booleanness.  Some code assumes an invariant that boolean
-	 types stay boolean and do not become 1-bit bit-field types.  */
-      if ((TREE_CODE (inner_type) == BOOLEAN_TYPE)
-	  != (TREE_CODE (outer_type) == BOOLEAN_TYPE))
+      /* Conversions from a non-base to a base type are not useless.
+	 This way we preserve the invariant to do arithmetic in
+	 base types only.  */
+      if (TREE_TYPE (inner_type)
+	  && TREE_TYPE (inner_type) != inner_type
+	  && (TREE_TYPE (outer_type) == outer_type
+	      || TREE_TYPE (outer_type) == NULL_TREE))
 	return false;
 
-      /* Preserve changes in the types minimum or maximum value.
-	 ???  Due to the way we handle sizetype as signed we need
-	 to jump through hoops here to make sizetype and size_type_node
-	 compatible.  */
-      if (!tree_int_cst_equal (fold_convert (outer_type,
-					     TYPE_MIN_VALUE (inner_type)),
-			       TYPE_MIN_VALUE (outer_type))
-	  || !tree_int_cst_equal (fold_convert (outer_type,
-						TYPE_MAX_VALUE (inner_type)),
-				  TYPE_MAX_VALUE (outer_type)))
-	return false;
+      /* We don't need to preserve changes in the types minimum or
+	 maximum value in general as these do not generate code
+	 unless the types precisions are different.  */
 
       return true;
     }
diff --git a/gcc/tree.def b/gcc/tree.def
index fc9408af2d8..3b7750a909d 100644
--- a/gcc/tree.def
+++ b/gcc/tree.def
@@ -485,7 +485,8 @@ DEFTREECODE (TARGET_EXPR, "target_expr", tcc_expression, 4)
    Operand 0 may be of any type.
    Operand 1 must have the same type as the entire expression, unless
    it unconditionally throws an exception, in which case it should
-   have VOID_TYPE.  The same constraints apply to operand 2.  */
+   have VOID_TYPE.  The same constraints apply to operand 2.  The
+   condition in operand 0 must be of integral type.  */
 DEFTREECODE (COND_EXPR, "cond_expr", tcc_expression, 3)
 
 /* Vector conditional expression. It is like COND_EXPR, but with