Re: [PATCH] Fix PR50189

[Richard Guenther <rguenther at suse dot de>]

On Wed, 12 Oct 2011, Richard Guenther wrote:

> 
> This changes VRP to use the type of the variable we record
> an assertion for to look for TYPE_MIN/MAX_VALUEs rather than
> the limit that it is tested against.  That makes sense anyway
> and happens to mitigate the wrong-code bug for the testcase
> in PR50189.
> 
> Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

Which shows I need to adjust types for plus/minus we build because
of possible mismatches.

Bootstrapped and tested on x86_64-unknown-linux-gnu, installed.

Richard.

2011-10-12  Paul Koning  <pkoning@gcc.gnu.org>

	PR tree-optimization/50189
	* tree-vrp.c (extract_range_from_assert): Use the type of
	the variable, not the limit.

	* g++.dg/torture/pr50189.C: New testcase.

Index: gcc/tree-vrp.c
===================================================================
*** gcc/tree-vrp.c	(revision 179850)
--- gcc/tree-vrp.c	(working copy)
*************** extract_range_from_assert (value_range_t
*** 1476,1482 ****
  
    limit = avoid_overflow_infinity (limit);
  
!   type = TREE_TYPE (limit);
    gcc_assert (limit != var);
  
    /* For pointer arithmetic, we only keep track of pointer equality
--- 1476,1482 ----
  
    limit = avoid_overflow_infinity (limit);
  
!   type = TREE_TYPE (var);
    gcc_assert (limit != var);
  
    /* For pointer arithmetic, we only keep track of pointer equality
*************** extract_range_from_assert (value_range_t
*** 1650,1657 ****
  	  /* For LT_EXPR, we create the range [MIN, MAX - 1].  */
  	  if (cond_code == LT_EXPR)
  	    {
! 	      tree one = build_int_cst (type, 1);
! 	      max = fold_build2 (MINUS_EXPR, type, max, one);
  	      if (EXPR_P (max))
  		TREE_NO_WARNING (max) = 1;
  	    }
--- 1650,1657 ----
  	  /* For LT_EXPR, we create the range [MIN, MAX - 1].  */
  	  if (cond_code == LT_EXPR)
  	    {
! 	      tree one = build_int_cst (TREE_TYPE (max), 1);
! 	      max = fold_build2 (MINUS_EXPR, TREE_TYPE (max), max, one);
  	      if (EXPR_P (max))
  		TREE_NO_WARNING (max) = 1;
  	    }
*************** extract_range_from_assert (value_range_t
*** 1685,1692 ****
  	  /* For GT_EXPR, we create the range [MIN + 1, MAX].  */
  	  if (cond_code == GT_EXPR)
  	    {
! 	      tree one = build_int_cst (type, 1);
! 	      min = fold_build2 (PLUS_EXPR, type, min, one);
  	      if (EXPR_P (min))
  		TREE_NO_WARNING (min) = 1;
  	    }
--- 1685,1692 ----
  	  /* For GT_EXPR, we create the range [MIN + 1, MAX].  */
  	  if (cond_code == GT_EXPR)
  	    {
! 	      tree one = build_int_cst (TREE_TYPE (min), 1);
! 	      min = fold_build2 (PLUS_EXPR, TREE_TYPE (min), min, one);
  	      if (EXPR_P (min))
  		TREE_NO_WARNING (min) = 1;
  	    }
Index: gcc/testsuite/g++.dg/torture/pr50189.C
===================================================================
*** gcc/testsuite/g++.dg/torture/pr50189.C	(revision 0)
--- gcc/testsuite/g++.dg/torture/pr50189.C	(revision 0)
***************
*** 0 ****
--- 1,121 ----
+ // { dg-do run }
+ // { dg-options "-fstrict-enums" }
+ 
+ extern "C" void abort (void);
+ class CCUTILS_KeyedScalarLevelPosition
+ {
+ public:
+ 
+     typedef enum
+     {
+         UNINITED = 0,
+         AT_BEGIN = 1,
+         AT_END = 2,
+         AT_KEY = 3
+ 
+     } position_t;
+ 
+     bool is_init() const
+     { return(m_timestamp != UNINITED); }
+ 
+     bool is_at_begin() const
+     { return(m_timestamp == AT_BEGIN); }
+ 
+     position_t get_state() const
+     {
+         return((m_timestamp >= AT_KEY)
+              ? AT_KEY
+              : ((position_t)m_timestamp));
+     }
+ 
+     void set_at_begin()
+     { m_timestamp = AT_BEGIN; }
+ 
+     unsigned int get_index() const
+     { return(m_index); }
+ 
+     void set_pos(unsigned int a_index, unsigned int a_timestmap)
+     {
+         m_index = a_index;
+         m_timestamp = a_timestmap;
+     }
+ 
+     bool check_pos(unsigned int a_num_entries, unsigned int a_timestamp) const
+     {
+         if (get_state() != AT_KEY)
+             return(false);
+ 
+         if (m_timestamp != a_timestamp)
+             return(false);
+ 
+         return(m_index < a_num_entries);
+     }
+ 
+     void set_not_init()
+     { m_timestamp = 0; }
+ 
+ private:
+ 
+     unsigned int m_timestamp;
+     unsigned int m_index;
+ 
+ };
+ 
+ class CCUTILS_KeyedScalarPosition
+ {
+ public:
+ 
+     CCUTILS_KeyedScalarLevelPosition m_L1;
+     CCUTILS_KeyedScalarLevelPosition m_L2;
+ };
+ 
+ class baz
+ {
+ public:
+     int *n[20];
+     unsigned int m_cur_array_len;
+     unsigned int m_timestamp;
+ 
+     unsigned int _get_timestamp() const
+     { return(m_timestamp); }
+ 
+     bool _check_L1_pos(const CCUTILS_KeyedScalarPosition &a_position) const
+     {
+         return(a_position.m_L1.check_pos(
+                    m_cur_array_len, _get_timestamp()));
+     }
+ 
+     void *next (CCUTILS_KeyedScalarPosition &);
+ };
+ 
+ void * baz::next (CCUTILS_KeyedScalarPosition &a_position)
+ {
+     if (a_position.m_L1.is_at_begin() || (!a_position.m_L1.is_init()))
+     {
+         a_position.m_L1.set_pos(0, _get_timestamp());
+         a_position.m_L2.set_at_begin();
+     }
+     else if (!_check_L1_pos(a_position))
+         return(0);
+ 
+     return n[a_position.m_L1.get_index ()];
+ }
+ 
+ int main (int, char **)
+ {
+     baz obj;
+     CCUTILS_KeyedScalarPosition a_pos;
+     void *ret;
+     int n[5];
+     
+     obj.n[0] = n;
+     obj.m_cur_array_len = 1;
+     obj.m_timestamp = 42;
+     
+     a_pos.m_L1.set_pos (0, 42);
+     
+     ret = obj.next (a_pos);
+     if (ret == 0)
+       abort ();
+     return 0;
+ }