Re: [PATCH] Fix PR34458, ICE in data-ref with using int_cst_value

[Richard Guenther <rguenther at suse dot de>]

On Wed, 9 Jan 2008, Richard Guenther wrote:

> 
> Fixed by using tree_low_cst instead.  For 4.4 we want to implement
> int_cst_value in terms of tree_low_cst instead (or get rid of 
> int_cst_value by replacing all callers) - not appropriate at this stage
> though.
> 
> The problem is that int_cst_value insists on the constants type being
> completely representable in a HOST_WIDE_INT.  But what (usually) matters
> is, whether the actual constant fits in a HOST_WIDE_INT - which is
> what tree_low_cst ensures.  64bit types are common, but constants that
> do not fit in a 32bit type not, so this avoids the ICE.
> 
> Note this doesn't fix the fundamental problem with data-ref, and as
> Zdenek mentions data-ref should possibly use double_ints for its
> calculations.
> 
> But this is an easy and obvious fix here.  Bootstrap and regtest in
> progress, I'll apply this after it completes.

Of course it isn't always _that_ easy.  So, here's what I committed.

Richard.

2008-01-09  Richard Guenther  <rguenther@suse.de>

	PR middle-end/34458
	* tree-data-ref.c (initialize_matrix_A): Use tree_low_cst,
	adjust return type.

	* gcc.c-torture/compile/pr34458.c: New testcase.

Index: testsuite/gcc.c-torture/compile/pr34458.c
===================================================================
*** testsuite/gcc.c-torture/compile/pr34458.c	(revision 0)
--- testsuite/gcc.c-torture/compile/pr34458.c	(revision 0)
***************
*** 0 ****
--- 1,16 ----
+ /* Testcase by Martin Michlmayr <tbm@cyrius.com> */
+ 
+ typedef struct
+ {
+   int data[1024];
+ }
+ Lint;
+ Lint lint_operate (Lint a, long long ammount)
+ {
+   int index;
+   Lint ret;
+   for (index = 0; index < 24; index++)
+     ret.data[index] =
+       a.data[index + ammount / 32 + 1] << a.data[index + ammount / 32];
+   return ret;
+ }
Index: tree-data-ref.c
===================================================================
*** tree-data-ref.c	(revision 131424)
--- tree-data-ref.c	(working copy)
*************** analyze_siv_subscript_cst_affine (tree c
*** 1820,1834 ****
  /* Helper recursive function for initializing the matrix A.  Returns
     the initial value of CHREC.  */
  
! static int
  initialize_matrix_A (lambda_matrix A, tree chrec, unsigned index, int mult)
  {
    gcc_assert (chrec);
  
    if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
!     return int_cst_value (chrec);
! 
!   A[index][0] = mult * int_cst_value (CHREC_RIGHT (chrec));
    return initialize_matrix_A (A, CHREC_LEFT (chrec), index + 1, mult);
  }
  
--- 1820,1843 ----
  /* Helper recursive function for initializing the matrix A.  Returns
     the initial value of CHREC.  */
  
! static HOST_WIDE_INT
  initialize_matrix_A (lambda_matrix A, tree chrec, unsigned index, int mult)
  {
+   tree type;
+ 
    gcc_assert (chrec);
  
+   type = TREE_TYPE (chrec);
    if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
!     return tree_low_cst (chrec, TYPE_UNSIGNED (type)
! 				&& !(TREE_CODE (type) == INTEGER_TYPE
! 				     && TYPE_IS_SIZETYPE (type)));
! 
!   type = TREE_TYPE (CHREC_RIGHT (chrec));
!   A[index][0] = mult * tree_low_cst (CHREC_RIGHT (chrec),
! 				     TYPE_UNSIGNED (type)
! 				     && !(TREE_CODE (type) == INTEGER_TYPE
! 					  && TYPE_IS_SIZETYPE (type)));
    return initialize_matrix_A (A, CHREC_LEFT (chrec), index + 1, mult);
  }