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[PATCH] Fix c/4389 (take 2)


On Wed, Feb 20, 2002 at 01:59:41PM -0500, Richard Kenner wrote:
>     I believe there has to be an TREE_UNSIGNED (TREE_TYPE (t))
>     check, though not where it used to be. IMHO it should look like:
> 
>               || (! pos && TREE_INT_CST_HIGH (t) == -1
>                   && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0
> 		  && ! TREE_UNSIGNED (TREE_TYPE (t)))
> 
> Yes, I think that's right.

Ok to commit Roger's patch plus the above fix then (bootstrapped and
regression tested on i386-redhat-linux, included below)?

> 
>     type of code will have to change to:
> 
>           HOST_WIDE_INT bitsize;
>     ...
>           if (host_integerp (bitsize, 0)
> 	      && tree_int_cst_sgn (bitsize) >= 0)
>             bitsize = tree_low_cst (bitsize, 0);
>           else
>             bitsize = -1;
> 
> Well, we treat all negative bitsizes as the same, so I think the added test
> accomplishes nothing in precisely this case.  

You're right, false alarm.

2002-02-20  Roger Sayle  <roger@eyesopen.com>
	    Jakub Jelinek  <jakub@redhat.com>

	PR c/4389
	* tree.c (host_integerp): Ensure that the constant integer is
	representable in a HOST_WIDE_INT or an unsigned HOST_WIDE_INT
	when pos is zero or non-zero respectively.  Clarify comment.
	* c-format.c (check_format_info_recurse): Fix host_integerp
	usage; the pos argument should be zero when assigning to a
	signed HOST_WIDE_INT.

	* gcc.dg/20020219-1.c: New test.

--- gcc/testsuite/gcc.dg/20020219-1.c.jj	Tue Feb 19 18:33:26 2002
+++ gcc/testsuite/gcc.dg/20020219-1.c	Wed Feb 20 17:49:04 2002
@@ -0,0 +1,28 @@
+/* PR c/4389
+   This testcase failed because host_integerp (x, 0) was returning
+   1 even for constants bigger than 2^31.  */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+extern void abort (void);
+extern void exit (int);
+struct A {
+  int a[10000][10000];
+};
+int b[2] = { 213151, 0 };
+
+void foo (struct A *x, int y)
+{
+  if (x->a[9999][9999] != x->a[y][y])
+    abort ();
+  if (x->a[9999][9999] != 213151)
+    abort ();
+}
+
+int main (void)
+{
+  struct A *x;
+  asm ("" : "=r" (x) : "0" (&b[1]));
+  foo (x - 1, 9999);
+  exit (0);
+}
--- gcc/tree.c.jj	Tue Feb 19 11:13:31 2002
+++ gcc/tree.c	Wed Feb 20 17:44:40 2002
@@ -3436,8 +3436,10 @@ tree_int_cst_compare (t1, t2)
     return 0;
 }
 
-/* Return 1 if T is an INTEGER_CST that can be represented in a single
-   HOST_WIDE_INT value.  If POS is nonzero, the result must be positive.  */
+/* Return 1 if T is an INTEGER_CST that can be manipulated efficiently on
+   the host.  If POS is zero, the value can be represented in a single
+   HOST_WIDE_INT.  If POS is nonzero, the value must be positive and can
+   be represented in a single unsigned HOST_WIDE_INT.  */
 
 int
 host_integerp (t, pos)
@@ -3449,9 +3451,9 @@ host_integerp (t, pos)
 	  && ((TREE_INT_CST_HIGH (t) == 0
 	       && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) >= 0)
 	      || (! pos && TREE_INT_CST_HIGH (t) == -1
-		  && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0)
-	      || (! pos && TREE_INT_CST_HIGH (t) == 0
-		  && TREE_UNSIGNED (TREE_TYPE (t)))));
+		  && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0
+		  && ! TREE_UNSIGNED (TREE_TYPE (t)))
+	      || (pos && TREE_INT_CST_HIGH (t) == 0)));
 }
 
 /* Return the HOST_WIDE_INT least significant bits of T if it is an
--- gcc/c-format.c.jj	Tue Nov 27 17:15:23 2001
+++ gcc/c-format.c	Wed Feb 20 17:47:22 2002
@@ -1,6 +1,6 @@
 /* Check calls to formatted I/O functions (-Wformat).
-   Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001
-   Free Software Foundation, Inc.
+   Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
+   2001, 2002 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -1516,13 +1516,12 @@ check_format_info_recurse (status, res, 
 	  res->number_non_literal++;
 	  return;
 	}
-      if (!host_integerp (arg1, 1))
+      if (!host_integerp (arg1, 0)
+	  || (offset = tree_low_cst (arg1, 0)) < 0)
 	{
 	  res->number_non_literal++;
 	  return;
 	}
-
-      offset = TREE_INT_CST_LOW (arg1);
     }
   if (TREE_CODE (format_tree) != ADDR_EXPR)
     {


	Jakub


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