re PR middle-end/49189 (infinite recursion in constant folder)

2011-05-27  Richard Guenther  <rguenther@suse.de>

	PR middle-end/49189
	* fold-const.c (fold_unary_loc): Do not re-fold folding conversions
	of comparisons.

	* gnat.dg/bit_packed_array5.adb: New testcase.
	* gnat.dg/bit_packed_array5.ads: Likewise.

From-SVN: r174330

5 files changed, 60 insertions, 7 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9574435..6271933 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2011-05-27  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/49189
+	* fold-const.c (fold_unary_loc): Do not re-fold folding conversions
+	of comparisons.
+
 2011-05-27  Bernd Schmidt  <bernds@codesourcery.com>
 
 	* haifa-sched.c (sched_scan_info): Remove.
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index ebb1d34..9a3f8cb 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -7660,15 +7660,19 @@ fold_unary_loc (location_t loc, enum tree_code code, tree type, tree op0)
       if (COMPARISON_CLASS_P (op0))
 	{
 	  /* If we have (type) (a CMP b) and type is an integral type, return
-	     new expression involving the new type.  */
+	     new expression involving the new type.  Canonicalize
+	     (type) (a CMP b) to (a CMP b) ? (type) true : (type) false for
+	     non-integral type.
+	     Do not fold the result as that would not simplify further, also
+	     folding again results in recursions.  */
 	  if (INTEGRAL_TYPE_P (type))
-	    return fold_build2_loc (loc, TREE_CODE (op0), type,
-				    TREE_OPERAND (op0, 0),
-				    TREE_OPERAND (op0, 1));
+	    return build2_loc (loc, TREE_CODE (op0), type,
+			       TREE_OPERAND (op0, 0),
+			       TREE_OPERAND (op0, 1));
 	  else
-	    return fold_build3_loc (loc, COND_EXPR, type, op0,
-				    fold_convert (type, boolean_true_node),
-				    fold_convert (type, boolean_false_node));
+	    return build3_loc (loc, COND_EXPR, type, op0,
+			       fold_convert (type, boolean_true_node),
+			       fold_convert (type, boolean_false_node));
 	}
 
       /* Handle cases of two conversions in a row.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a6ce74b..2bf68b3 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2011-05-27  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/49189
+	* gnat.dg/bit_packed_array5.adb: New testcase.
+	* gnat.dg/bit_packed_array5.ads: Likewise.
+
 2011-05-26  Jason Merrill  <jason@redhat.com>
 
 	* g++.dg/cpp0x/friend1.C: New.
diff --git a/gcc/testsuite/gnat.dg/bit_packed_array5.adb b/gcc/testsuite/gnat.dg/bit_packed_array5.adb
new file mode 100644
index 0000000..de574fb
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/bit_packed_array5.adb
@@ -0,0 +1,21 @@
+with System;
+
+package body Bit_Packed_Array5 is
+
+   function Inv (Word : Word_Type) return Word_Type is
+      W : Word_Type := Word;
+      pragma Volatile (W);
+
+      A_W : constant System.Address := W'Address;
+
+      V : Short_Bit_Array_Type;
+      for V'Address use A_W;
+      pragma Volatile (V);
+   begin
+      for I in V'Range loop
+          V (I) := not V (I);
+      end loop;
+      return W;
+   end;
+
+end Bit_Packed_Array5;
diff --git a/gcc/testsuite/gnat.dg/bit_packed_array5.ads b/gcc/testsuite/gnat.dg/bit_packed_array5.ads
new file mode 100644
index 0000000..8d335f0
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/bit_packed_array5.ads
@@ -0,0 +1,16 @@
+-- { dg-do compile }
+
+package Bit_Packed_Array5 is
+
+   type Bit_Array is array (Integer range <>) of Boolean;
+   pragma Pack (Bit_Array);
+
+   type Short_Bit_Array_Type is new Bit_Array (0 .. 15);
+   for Short_Bit_Array_Type'Size use 16;
+
+   type Word_Type is range 0 .. 65535;
+   for Word_Type'Size use 16;
+
+   function Inv (Word : Word_Type) return Word_Type;
+
+end Bit_Packed_Array5;