tree-flow.h (okay_component_ref_for_subvars): Remove.

2005-12-15  Richard Guenther  <rguenther@suse.de>

	* tree-flow.h (okay_component_ref_for_subvars): Remove.
	(get_ref_base_and_extent): Declare.
	* tree-dfa.c (okay_component_ref_for_subvars): Remove.
	(get_ref_base_and_extent): New function.
	* tree-ssa-alias.c (find_used_portions): Use it.
	* tree-ssa-structalias.c (get_constraint_for_component_ref):
	Likewise.
	* tree-ssa-operands.c (get_expr_operands): Likewise.

From-SVN: r108568

6 files changed, 182 insertions, 83 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index de3e458..dd6bda6 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2005-12-15  Richard Guenther  <rguenther@suse.de>
+
+	* tree-flow.h (okay_component_ref_for_subvars): Remove.
+	(get_ref_base_and_extent): Declare.
+	* tree-dfa.c (okay_component_ref_for_subvars): Remove.
+	(get_ref_base_and_extent): New function.
+	* tree-ssa-alias.c (find_used_portions): Use it.
+	* tree-ssa-structalias.c (get_constraint_for_component_ref):
+	Likewise.
+	* tree-ssa-operands.c (get_expr_operands): Likewise.
+
 2005-12-15  Paolo Bonzini  <bonzini@gnu.org>
 
         * combine.c: Remove force_to_mode's fourth parameter.
diff --git a/gcc/tree-dfa.c b/gcc/tree-dfa.c
index 3f89047..771c9f8 100644
--- a/gcc/tree-dfa.c
+++ b/gcc/tree-dfa.c
@@ -792,45 +792,157 @@ find_new_referenced_vars (tree *stmt_p)
 }
 
 
-/* If REF is a COMPONENT_REF for a structure that can have sub-variables, and
-   we know where REF is accessing, return the variable in REF that has the
-   sub-variables.  If the return value is not NULL, POFFSET will be the
-   offset, in bits, of REF inside the return value, and PSIZE will be the
-   size, in bits, of REF inside the return value.  */
+/* If REF is a handled component reference for a structure, return the
+   base variable.  The access range is delimited by bit positions *POFFSET and
+   *POFFSET + *PMAX_SIZE.  The access size is *PSIZE bits.  If either
+   *PSIZE or *PMAX_SIZE is -1, they could not be determined.  If *PSIZE
+   and *PMAX_SIZE are equal, the access is non-variable.  */
 
 tree
-okay_component_ref_for_subvars (tree ref, unsigned HOST_WIDE_INT *poffset,
-				unsigned HOST_WIDE_INT *psize)
+get_ref_base_and_extent (tree exp, HOST_WIDE_INT *poffset,
+			 HOST_WIDE_INT *psize,
+			 HOST_WIDE_INT *pmax_size)
 {
-  tree result = NULL;
-  HOST_WIDE_INT bitsize;
-  HOST_WIDE_INT bitpos;
-  tree offset;
-  enum machine_mode mode;
-  int unsignedp;
-  int volatilep;
-
-  gcc_assert (!SSA_VAR_P (ref));
-  *poffset = 0;  
-  *psize = (unsigned int) -1;
-  
-  if (ref_contains_array_ref (ref))
-    return result;
-  ref = get_inner_reference (ref, &bitsize, &bitpos, &offset, &mode,
-			     &unsignedp, &volatilep, false);
-  if (TREE_CODE (ref) == INDIRECT_REF)
-    return result;
-  else if (offset == NULL && bitsize != -1 && SSA_VAR_P (ref))
+  HOST_WIDE_INT bitsize = -1;
+  HOST_WIDE_INT maxsize = -1;
+  tree size_tree = NULL_TREE;
+  tree bit_offset = bitsize_zero_node;
+
+  gcc_assert (!SSA_VAR_P (exp));
+
+  /* First get the final access size from just the outermost expression.  */
+  if (TREE_CODE (exp) == COMPONENT_REF)
+    size_tree = DECL_SIZE (TREE_OPERAND (exp, 1));
+  else if (TREE_CODE (exp) == BIT_FIELD_REF)
+    size_tree = TREE_OPERAND (exp, 1);
+  else
     {
-      *poffset = bitpos;      
-      *psize = bitsize;
-      if (get_subvars_for_var (ref) != NULL)
-	return ref;
+      enum machine_mode mode = TYPE_MODE (TREE_TYPE (exp));
+      if (mode == BLKmode)
+	size_tree = TYPE_SIZE (TREE_TYPE (exp));
+      else
+	bitsize = GET_MODE_BITSIZE (mode);
     }
-  else if (SSA_VAR_P (ref))
+  if (size_tree != NULL_TREE)
     {
-      if (get_subvars_for_var (ref) != NULL)
-	return ref;
+      if (! host_integerp (size_tree, 1))
+	bitsize = -1;
+      else
+	bitsize = TREE_INT_CST_LOW (size_tree);
     }
-  return NULL_TREE;
+
+  /* Initially, maxsize is the same as the accessed element size.
+     In the following it will only grow (or become -1).  */
+  maxsize = bitsize;
+
+  /* Compute cumulative bit-offset for nested component-refs and array-refs,
+     and find the ultimate containing object.  */
+  while (1)
+    {
+      switch (TREE_CODE (exp))
+	{
+	case BIT_FIELD_REF:
+	  bit_offset = size_binop (PLUS_EXPR, bit_offset,
+				   TREE_OPERAND (exp, 2));
+	  break;
+
+	case COMPONENT_REF:
+	  {
+	    tree field = TREE_OPERAND (exp, 1);
+	    tree this_offset = component_ref_field_offset (exp);
+
+	    if (this_offset && TREE_CODE (this_offset) == INTEGER_CST)
+	      {
+		this_offset = size_binop (MULT_EXPR,
+					  fold_convert (bitsizetype,
+							this_offset),
+					  bitsize_unit_node);
+		bit_offset = size_binop (PLUS_EXPR,
+				         bit_offset, this_offset);
+		bit_offset = size_binop (PLUS_EXPR, bit_offset,
+					 DECL_FIELD_BIT_OFFSET (field));
+	      }
+	    else
+	      {
+		tree csize = TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp, 0)));
+		/* We need to adjust maxsize to the whole structure bitsize.
+		   But we can subtract any constant offset seen sofar,
+		   because that would get us out of the structure otherwise.  */
+		if (maxsize != -1
+		    && csize && host_integerp (csize, 1))
+		  {
+		    maxsize = (TREE_INT_CST_LOW (csize)
+			       - TREE_INT_CST_LOW (bit_offset));
+		  }
+		else
+		  maxsize = -1;
+	      }
+	  }
+	  break;
+
+	case ARRAY_REF:
+	case ARRAY_RANGE_REF:
+	  {
+	    tree index = TREE_OPERAND (exp, 1);
+	    tree low_bound = array_ref_low_bound (exp);
+	    tree unit_size = array_ref_element_size (exp);
+
+	    if (! integer_zerop (low_bound))
+	      index = fold_build2 (MINUS_EXPR, TREE_TYPE (index),
+				   index, low_bound);
+	    index = size_binop (MULT_EXPR,
+				fold_convert (sizetype, index), unit_size);
+	    if (TREE_CODE (index) == INTEGER_CST)
+	      {
+		index = size_binop (MULT_EXPR,
+				    fold_convert (bitsizetype, index),
+				    bitsize_unit_node);
+		bit_offset = size_binop (PLUS_EXPR, bit_offset, index);
+	      }
+	    else
+	      {
+		tree asize = TYPE_SIZE (TREE_TYPE (TREE_OPERAND (exp, 0)));
+		/* We need to adjust maxsize to the whole array bitsize.
+		   But we can subtract any constant offset seen sofar,
+		   because that would get us outside of the array otherwise.  */
+		if (maxsize != -1
+		    && asize && host_integerp (asize, 1))
+		  {
+		    maxsize = (TREE_INT_CST_LOW (asize)
+			       - TREE_INT_CST_LOW (bit_offset));
+		  }
+		else
+		  maxsize = -1;
+	      }
+	  }
+	  break;
+
+	case REALPART_EXPR:
+	  break;
+
+	case IMAGPART_EXPR:
+	  bit_offset = size_binop (PLUS_EXPR, bit_offset,
+				   bitsize_int (bitsize));
+	  break;
+
+	case VIEW_CONVERT_EXPR:
+	  /* ???  We probably should give up here and bail out.  */
+	  break;
+
+	default:
+	  goto done;
+	}
+
+      exp = TREE_OPERAND (exp, 0);
+    }
+ done:
+
+  /* ???  Due to negative offsets in ARRAY_REF we can end up with
+     negative bit_offset here.  We might want to store a zero offset
+     in this case.  */
+  *poffset = TREE_INT_CST_LOW (bit_offset);
+  *psize = bitsize;
+  *pmax_size = maxsize;
+
+  return exp;
 }
diff --git a/gcc/tree-flow.h b/gcc/tree-flow.h
index 62b8027..9ebfeb8 100644
--- a/gcc/tree-flow.h
+++ b/gcc/tree-flow.h
@@ -592,8 +592,8 @@ static inline subvar_t get_subvars_for_var (tree);
 static inline tree get_subvar_at (tree, unsigned HOST_WIDE_INT);
 static inline bool ref_contains_array_ref (tree);
 static inline bool array_ref_contains_indirect_ref (tree);
-extern tree okay_component_ref_for_subvars (tree, unsigned HOST_WIDE_INT *,
-					    unsigned HOST_WIDE_INT *);
+extern tree get_ref_base_and_extent (tree, HOST_WIDE_INT *,
+				     HOST_WIDE_INT *, HOST_WIDE_INT *);
 static inline bool var_can_have_subvars (tree);
 static inline bool overlap_subvar (unsigned HOST_WIDE_INT,
 				   unsigned HOST_WIDE_INT,
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 1a9c006..d7d11c1 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -2695,16 +2695,14 @@ find_used_portions (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
     case COMPONENT_REF:
       {
 	HOST_WIDE_INT bitsize;
+	HOST_WIDE_INT bitmaxsize;
 	HOST_WIDE_INT bitpos;
-	tree offset;
-	enum machine_mode mode;
-	int unsignedp;
-	int volatilep;	
 	tree ref;
-	ref = get_inner_reference (*tp, &bitsize, &bitpos, &offset, &mode,
-				   &unsignedp, &volatilep, false);
-	if (DECL_P (ref) && offset == NULL && bitsize != -1)
-	  {	    
+	ref = get_ref_base_and_extent (*tp, &bitpos, &bitsize, &bitmaxsize);
+	if (DECL_P (ref)
+	    && var_can_have_subvars (ref)
+	    && bitmaxsize != -1)
+	  {
 	    size_t uid = DECL_UID (ref);
 	    used_part_t up;
 
@@ -2712,37 +2710,18 @@ find_used_portions (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
 
 	    if (bitpos <= up->minused)
 	      up->minused = bitpos;
-	    if ((bitpos + bitsize >= up->maxused))
-	      up->maxused = bitpos + bitsize;	    
+	    if ((bitpos + bitmaxsize >= up->maxused))
+	      up->maxused = bitpos + bitmaxsize;
 
-	    up->explicit_uses = true;
+	    if (bitsize == bitmaxsize)
+	      up->explicit_uses = true;
+	    else
+	      up->implicit_uses = true;
 	    up_insert (uid, up);
 
 	    *walk_subtrees = 0;
 	    return NULL_TREE;
 	  }
-	else if (DECL_P (ref))
-	  {
-	    if (DECL_SIZE (ref)
-		&& var_can_have_subvars (ref)
-		&& TREE_CODE (DECL_SIZE (ref)) == INTEGER_CST)
-	      {
-		used_part_t up;
-		size_t uid = DECL_UID (ref);
-
-		up = get_or_create_used_part_for (uid);
-
-		up->minused = 0;
-		up->maxused = TREE_INT_CST_LOW (DECL_SIZE (ref));
-
-		up->implicit_uses = true;
-
-		up_insert (uid, up);
-
-		*walk_subtrees = 0;
-		return NULL_TREE;
-	      }
-	  }
       }
       break;
       /* This is here to make sure we mark the entire base variable as used
diff --git a/gcc/tree-ssa-operands.c b/gcc/tree-ssa-operands.c
index c75f30c..0e0f365 100644
--- a/gcc/tree-ssa-operands.c
+++ b/gcc/tree-ssa-operands.c
@@ -1133,25 +1133,26 @@ get_expr_operands (tree stmt, tree *expr_p, int flags)
     case IMAGPART_EXPR:
       {
 	tree ref;
-	unsigned HOST_WIDE_INT offset, size;
+	HOST_WIDE_INT offset, size, maxsize;
  	/* This component ref becomes an access to all of the subvariables
 	   it can touch,  if we can determine that, but *NOT* the real one.
 	   If we can't determine which fields we could touch, the recursion
 	   will eventually get to a variable and add *all* of its subvars, or
 	   whatever is the minimum correct subset.  */
 
-	ref = okay_component_ref_for_subvars (expr, &offset, &size);
-	if (ref)
+	ref = get_ref_base_and_extent (expr, &offset, &size, &maxsize);
+	if (SSA_VAR_P (ref) && get_subvars_for_var (ref))
 	  {	  
 	    subvar_t svars = get_subvars_for_var (ref);
 	    subvar_t sv;
 	    for (sv = svars; sv; sv = sv->next)
 	      {
 		bool exact;		
-		if (overlap_subvar (offset, size, sv, &exact))
+		if (overlap_subvar (offset, maxsize, sv, &exact))
 		  {
 	            int subvar_flags = flags;
-		    if (!exact)
+		    if (!exact
+			|| size != maxsize)
 		      subvar_flags &= ~opf_kill_def;
 		    add_stmt_operand (&sv->var, s_ann, subvar_flags);
 		  }
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 7f3446b..9ed4d78 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -2348,11 +2348,8 @@ get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
 {
   tree orig_t = t;
   HOST_WIDE_INT bitsize = -1;
+  HOST_WIDE_INT bitmaxsize = -1;
   HOST_WIDE_INT bitpos;
-  tree offset = NULL_TREE;
-  enum machine_mode mode;
-  int unsignedp;
-  int volatilep;
   tree forzero;
   struct constraint_expr *result;
   unsigned int beforelength = VEC_length (ce_s, *results);
@@ -2374,8 +2371,7 @@ get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
       return;
     }
  
-  t = get_inner_reference (t, &bitsize, &bitpos, &offset, &mode,
-			   &unsignedp, &volatilep, false);
+  t = get_ref_base_and_extent (t, &bitpos, &bitsize, &bitmaxsize);
   get_constraint_for (t, results, anyoffset);
   result = VEC_last (ce_s, *results);
 
@@ -2386,11 +2382,11 @@ get_constraint_for_component_ref (tree t, VEC(ce_s, heap) **results,
     result->type = SCALAR;
   
   /* If we know where this goes, then yay. Otherwise, booo. */
-
-  if (offset == NULL && bitsize != -1)
+  if (bitmaxsize != -1
+      && bitsize == bitmaxsize)
     {
       result->offset = bitpos;
-    }	
+    }
   /* FIXME: Handle the DEREF case.  */
   else if (anyoffset && result->type != DEREF)
     {