[PATCH] Better propagation of flags in access trees of SRA

[Martin Jambor]

Hi,

the way we propagate flags in SRA access tree has evolved in an
unfortunate way, this patch simplifies the whole thing while doing
exactly the same thing.

Bootstrapped and tested on x86_64-linux, OK for trunk?

Thanks,

Martin



2011-06-06  Martin Jambor  <mjambor@suse.cz>

	* tree-sra.c (mark_rw_status): Removed.
	(analyze_access_subtree): New parameter parent instead of
	mark_read and mark_write, propagate from that.

Index: src/gcc/tree-sra.c
===================================================================
*** src.orig/gcc/tree-sra.c
--- src/gcc/tree-sra.c
*************** expr_with_var_bounded_array_refs_p (tree
*** 1864,1871 ****
    return false;
  }
  
- enum mark_rw_status { SRA_MRRW_NOTHING, SRA_MRRW_DIRECT, SRA_MRRW_ASSIGN};
- 
  /* Analyze the subtree of accesses rooted in ROOT, scheduling replacements when
     both seeming beneficial and when ALLOW_REPLACEMENTS allows it.  Also set all
     sorts of access flags appropriately along the way, notably always set
--- 1864,1869 ----
*************** enum mark_rw_status { SRA_MRRW_NOTHING,
*** 1905,1913 ****
     1	1	1	1	Yes		Any of the above yeses  */
  
  static bool
! analyze_access_subtree (struct access *root, bool allow_replacements,
! 			enum mark_rw_status mark_read,
! 			enum mark_rw_status mark_write)
  {
    struct access *child;
    HOST_WIDE_INT limit = root->offset + root->size;
--- 1903,1910 ----
     1	1	1	1	Yes		Any of the above yeses  */
  
  static bool
! analyze_access_subtree (struct access *root, struct access *parent,
! 			bool allow_replacements)
  {
    struct access *child;
    HOST_WIDE_INT limit = root->offset + root->size;
*************** analyze_access_subtree (struct access *r
*** 1915,1943 ****
    bool scalar = is_gimple_reg_type (root->type);
    bool hole = false, sth_created = false;
  
!   if (root->grp_assignment_read)
!     mark_read = SRA_MRRW_ASSIGN;
!   else if (mark_read == SRA_MRRW_ASSIGN)
!     {
!       root->grp_read = 1;
!       root->grp_assignment_read = 1;
!     }
!   else if (mark_read == SRA_MRRW_DIRECT)
!     root->grp_read = 1;
!   else if (root->grp_read)
!     mark_read = SRA_MRRW_DIRECT;
! 
!   if (root->grp_assignment_write)
!     mark_write = SRA_MRRW_ASSIGN;
!   else if (mark_write == SRA_MRRW_ASSIGN)
      {
!       root->grp_write = 1;
!       root->grp_assignment_write = 1;
      }
-   else if (mark_write == SRA_MRRW_DIRECT)
-     root->grp_write = 1;
-   else if (root->grp_write)
-     mark_write = SRA_MRRW_DIRECT;
  
    if (root->grp_unscalarizable_region)
      allow_replacements = false;
--- 1912,1928 ----
    bool scalar = is_gimple_reg_type (root->type);
    bool hole = false, sth_created = false;
  
!   if (parent)
      {
!       if (parent->grp_read)
! 	root->grp_read = 1;
!       if (parent->grp_assignment_read)
! 	root->grp_assignment_read = 1;
!       if (parent->grp_write)
! 	root->grp_write = 1;
!       if (parent->grp_assignment_write)
! 	root->grp_assignment_write = 1;
      }
  
    if (root->grp_unscalarizable_region)
      allow_replacements = false;
*************** analyze_access_subtree (struct access *r
*** 1952,1960 ****
        else
  	covered_to += child->size;
  
!       sth_created |= analyze_access_subtree (child,
! 					     allow_replacements && !scalar,
! 					     mark_read, mark_write);
  
        root->grp_unscalarized_data |= child->grp_unscalarized_data;
        hole |= !child->grp_covered;
--- 1937,1944 ----
        else
  	covered_to += child->size;
  
!       sth_created |= analyze_access_subtree (child, root,
! 					     allow_replacements && !scalar);
  
        root->grp_unscalarized_data |= child->grp_unscalarized_data;
        hole |= !child->grp_covered;
*************** analyze_access_trees (struct access *acc
*** 2002,2009 ****
  
    while (access)
      {
!       if (analyze_access_subtree (access, true,
! 				  SRA_MRRW_NOTHING, SRA_MRRW_NOTHING))
  	ret = true;
        access = access->next_grp;
      }
--- 1986,1992 ----
  
    while (access)
      {
!       if (analyze_access_subtree (access, NULL, true))
  	ret = true;
        access = access->next_grp;
      }