re PR middle-end/27529 (Does not fold (char *)(size_t)char_ptr or (size_t)(char *)size_t_var)

2006-05-11  Richard Guenther  <rguenther@suse.de>

	PR middle-end/27529
	* fold-const.c (fold_unary): Handle intermediate conversion
	to a pointer type like intermediate conversion to an integer
	type in folding of (T1)(T2)var to var.
	Match the code to the comment in the final conversion for
	(T1)(T2)var to (T1)var regarding to type precision.  Rather
	than disallow T1 being of pointer type, assert that both T1
	and var are of pointer type or not.  Make sure not to fall
	over the frontends lazyness wrt array to pointer decay though.

	* gcc.dg/tree-ssa/foldcast-1.c: New testcase.

From-SVN: r113692

gcc/ChangeLog

@@ -1,3 +1,15 @@
+2006-05-11  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/27529
+	* fold-const.c (fold_unary): Handle intermediate conversion
+	to a pointer type like intermediate conversion to an integer
+	type in folding of (T1)(T2)var to var.
+	Match the code to the comment in the final conversion for
+	(T1)(T2)var to (T1)var regarding to type precision.  Rather
+	than disallow T1 being of pointer type, assert that both T1
+	and var are of pointer type or not.  Make sure not to fall
+	over the frontends lazyness wrt array to pointer decay though.
+
 2006-05-10  Richard Earnshaw  <rearnsha@arm.com>
 
 	* arm.c (arm_struct_value_rtx): Delete.

gcc/fold-const.c

@@ -7323,7 +7323,8 @@ fold_unary (enum tree_code code, tree type, tree op0)
 	     type via an object of identical or wider precision, neither
 	     conversion is needed.  */
 	  if (TYPE_MAIN_VARIANT (inside_type) == TYPE_MAIN_VARIANT (type)
-	      && ((inter_int && final_int) || (inter_float && final_float))
+	      && (((inter_int || inter_ptr) && final_int)
+		  || (inter_float && final_float))
 	      && inter_prec >= final_prec)
 	    return fold_build1 (code, type, TREE_OPERAND (op0, 0));
 
@@ -7362,10 +7363,13 @@ fold_unary (enum tree_code code, tree type, tree op0)
 	     - the initial type is a pointer type and the precisions of the
 	       intermediate and final types differ, or
 	     - the final type is a pointer type and the precisions of the
-	       initial and intermediate types differ.  */
+	       initial and intermediate types differ.
+	     - the final type is a pointer type and the initial type not
+	     - the initial type is a pointer to an array and the final type
+	       not.  */
 	  if (! inside_float && ! inter_float && ! final_float
 	      && ! inside_vec && ! inter_vec && ! final_vec
-	      && (inter_prec > inside_prec || inter_prec > final_prec)
+	      && (inter_prec >= inside_prec || inter_prec >= final_prec)
 	      && ! (inside_int && inter_int
 		    && inter_unsignedp != inside_unsignedp
 		    && inter_prec < final_prec)
@@ -7375,7 +7379,10 @@ fold_unary (enum tree_code code, tree type, tree op0)
 	      && ! (final_ptr && inside_prec != inter_prec)
 	      && ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (type))
 		    && TYPE_MODE (type) == TYPE_MODE (inter_type))
-	      && ! final_ptr)
+	      && final_ptr == inside_ptr
+	      && ! (inside_ptr
+		    && TREE_CODE (TREE_TYPE (inside_type)) == ARRAY_TYPE
+		    && TREE_CODE (TREE_TYPE (type)) != ARRAY_TYPE))
 	    return fold_build1 (code, type, TREE_OPERAND (op0, 0));
 	}
 

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2006-05-11  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/27529
+	* gcc.dg/tree-ssa/foldcast-1.c: New testcase.
+
 2006-05-10  Janis Johnson  <janis187@us.ibm.com>
 
 	* lib/target-supports-dg.exp (check-flags): New.

gcc/testsuite/gcc.dg/tree-ssa/foldcast-1.c

@@ -0,0 +1,16 @@
+/* { dg-do "compile" } */
+/* { dg-options "-fdump-tree-original" } */
+
+typedef int ssize_t __attribute__((mode(pointer)));
+ssize_t foo (ssize_t x)
+{
+  return (ssize_t)(char *)x;
+}
+
+char *bar (char *x)
+{
+  return (char *)(ssize_t)x;
+}
+
+/* { dg-final { scan-tree-dump-times "return x;" 2 "original" } } */
+/* { dg-final { cleanup-tree-dump "original" } } */