re PR ada/18817 (ACATS c380004 fails at run time)

	PR ada/18817
	* utils.c (max_size): Perform constant folding of (A ? B : C) - D
	into A ? B - D : C - D when calculating the size of a MINUS_EXPR.

From-SVN: r116964

gcc/ada/ChangeLog

+2006-09-15  Roger Sayle  <roger@eyesopen.com>
+
+	PR ada/18817
+	* utils.c (max_size): Perform constant folding of (A ? B : C) - D
+	into A ? B - D : C - D when calculating the size of a MINUS_EXPR.
+
 2006-09-13  Olivier Hainque  <hainque@adacore.com>
 
 	PR ada/29025

gcc/ada/utils.c

@@ -2072,6 +2072,22 @@ max_size (tree exp, bool max_p)
 	  if (code == COMPOUND_EXPR)
 	    return max_size (TREE_OPERAND (exp, 1), max_p);
 
+	  /* Calculate "(A ? B : C) - D" as "A ? B - D : C - D" which
+	     may provide a tighter bound on max_size.  */
+	  if (code == MINUS_EXPR
+	      && TREE_CODE (TREE_OPERAND (exp, 0)) == COND_EXPR)
+	    {
+	      tree lhs = fold_build2 (MINUS_EXPR, type,
+				      TREE_OPERAND (TREE_OPERAND (exp, 0), 1),
+				      TREE_OPERAND (exp, 1));
+	      tree rhs = fold_build2 (MINUS_EXPR, type,
+				      TREE_OPERAND (TREE_OPERAND (exp, 0), 2),
+				      TREE_OPERAND (exp, 1));
+	      return fold_build2 (max_p ? MAX_EXPR : MIN_EXPR, type,
+				  max_size (lhs, max_p),
+				  max_size (rhs, max_p));
+	    }
+
 	  {
 	    tree lhs = max_size (TREE_OPERAND (exp, 0), max_p);
 	    tree rhs = max_size (TREE_OPERAND (exp, 1),

gcc/testsuite/ada/acats/norun.lst

-c380004
 c52103x
 c52104x
 c52104y
@@ -7,6 +6,5 @@ cb1010c
 cb1010d
 templat
 # Tests must be sorted in alphabetical order
-# c380004: should be front-end compile time error, PR ada/18817
 # c52103x, c52104x, c52104y: -fstack-check doesn't work, PR middle-end/20548
 # cb1010a, cb1010c, cb1010d: likewise