[PATCH] Fix PR56384

[Richard Biener <rguenther at suse dot de>]

This fixes PHI value-numbering which did not correctly distinguish
types in case of still VN_TOP PHI arguments.

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

Richard.

2013-02-19  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/56384
	* tree-ssa-sccvn.h (struct vn_phi_s): Add type member.
	(vn_hash_type): Split out from ...
	(vn_hash_constant_with_type): ... here.
	* tree-ssa-sccvn.c (vn_phi_compute_hash): Use vn_hash_type.
	(vn_phi_eq): Compare types from vn_phi_s structure.
	(vn_phi_lookup): Populate vn_phi_s type.
	(vn_phi_insert): Likewise.

	* gcc.dg/torture/pr56384.c: New testcase.

Index: gcc/tree-ssa-sccvn.h
===================================================================
*** gcc/tree-ssa-sccvn.h	(revision 196134)
--- gcc/tree-ssa-sccvn.h	(working copy)
*************** typedef struct vn_phi_s
*** 67,72 ****
--- 67,73 ----
    hashval_t hashcode;
    vec<tree> phiargs;
    basic_block block;
+   tree type;
    tree result;
  } *vn_phi_t;
  typedef const struct vn_phi_s *const_vn_phi_t;
*************** typedef struct vn_constant_s
*** 122,138 ****
  enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
  enum vn_kind vn_get_stmt_kind (gimple);
  
  /* Hash the constant CONSTANT with distinguishing type incompatible
     constants in the types_compatible_p sense.  */
  
  static inline hashval_t
  vn_hash_constant_with_type (tree constant)
  {
-   tree type = TREE_TYPE (constant);
    return (iterative_hash_expr (constant, 0)
! 	  + INTEGRAL_TYPE_P (type)
! 	  + (INTEGRAL_TYPE_P (type)
! 	     ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
  }
  
  /* Compare the constants C1 and C2 with distinguishing type incompatible
--- 123,147 ----
  enum vn_kind { VN_NONE, VN_CONSTANT, VN_NARY, VN_REFERENCE, VN_PHI };
  enum vn_kind vn_get_stmt_kind (gimple);
  
+ /* Hash the type TYPE using bits that distinguishes it in the
+    types_compatible_p sense.  */
+ 
+ static inline hashval_t
+ vn_hash_type (tree type)
+ {
+   return (INTEGRAL_TYPE_P (type)
+ 	  + (INTEGRAL_TYPE_P (type)
+ 	     ? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
+ }
+ 
  /* Hash the constant CONSTANT with distinguishing type incompatible
     constants in the types_compatible_p sense.  */
  
  static inline hashval_t
  vn_hash_constant_with_type (tree constant)
  {
    return (iterative_hash_expr (constant, 0)
! 	  + vn_hash_type (TREE_TYPE (constant)));
  }
  
  /* Compare the constants C1 and C2 with distinguishing type incompatible
Index: gcc/tree-ssa-sccvn.c
===================================================================
*** gcc/tree-ssa-sccvn.c	(revision 196134)
--- gcc/tree-ssa-sccvn.c	(working copy)
*************** vn_phi_compute_hash (vn_phi_t vp1)
*** 2401,2410 ****
  
    /* If all PHI arguments are constants we need to distinguish
       the PHI node via its type.  */
!   type = TREE_TYPE (vp1->phiargs[0]);
!   result += (INTEGRAL_TYPE_P (type)
! 	     + (INTEGRAL_TYPE_P (type)
! 		? TYPE_PRECISION (type) + TYPE_UNSIGNED (type) : 0));
  
    FOR_EACH_VEC_ELT (vp1->phiargs, i, phi1op)
      {
--- 2401,2408 ----
  
    /* If all PHI arguments are constants we need to distinguish
       the PHI node via its type.  */
!   type = vp1->type;
!   result += vn_hash_type (type);
  
    FOR_EACH_VEC_ELT (vp1->phiargs, i, phi1op)
      {
*************** vn_phi_eq (const void *p1, const void *p
*** 2443,2450 ****
  
        /* If the PHI nodes do not have compatible types
  	 they are not the same.  */
!       if (!types_compatible_p (TREE_TYPE (vp1->phiargs[0]),
! 			       TREE_TYPE (vp2->phiargs[0])))
  	return false;
  
        /* Any phi in the same block will have it's arguments in the
--- 2441,2447 ----
  
        /* If the PHI nodes do not have compatible types
  	 they are not the same.  */
!       if (!types_compatible_p (vp1->type, vp2->type))
  	return false;
  
        /* Any phi in the same block will have it's arguments in the
*************** vn_phi_lookup (gimple phi)
*** 2484,2489 ****
--- 2481,2487 ----
        def = TREE_CODE (def) == SSA_NAME ? SSA_VAL (def) : def;
        shared_lookup_phiargs.safe_push (def);
      }
+   vp1.type = TREE_TYPE (gimple_phi_result (phi));
    vp1.phiargs = shared_lookup_phiargs;
    vp1.block = gimple_bb (phi);
    vp1.hashcode = vn_phi_compute_hash (&vp1);
*************** vn_phi_insert (gimple phi, tree result)
*** 2516,2521 ****
--- 2514,2520 ----
        args.safe_push (def);
      }
    vp1->value_id = VN_INFO (result)->value_id;
+   vp1->type = TREE_TYPE (gimple_phi_result (phi));
    vp1->phiargs = args;
    vp1->block = gimple_bb (phi);
    vp1->result = result;