2008-06-28 Richard Guenther <rguenther@suse.de>

	* tree-ssa-structalias.c (callused_id, var_callused,
	callused_tree): Add.
	(handle_pure_call): New function.
	(find_func_aliases): Call it.
	(find_what_p_points_to): Handle the call-used set.
	(clobber_what_escaped): Likewise.
	(compute_call_used_vars): New function.
	(init_base_vars): Init the call-used variable.
	(do_sd_constraint): Do not propagate the solution from CALLUSED
	but use CALLUSED as a placeholder.
	(solve_graph): Likewise.
	* tree-flow-inline.h (gimple_call_used_vars): New function.
	* tree-flow.h (struct gimple_df): Add call_used_vars bitmap.
	(compute_call_used_vars): Declare.
	* tree-ssa-alias.c (set_initial_properties): Call
	compute_call_used_vars.
	(reset_alias_info): Clear call-used variables.
	(add_call_clobber_ops): Assert we are not called for const/pure
	functions.  Remove handling of them.
	(add_call_read_ops): Handle pure functions by adding the
	call-used set of variables as VUSEs.
	* tree-ssa.c (init_tree_ssa): Allocate call-used bitmap.
	(delete_tree_ssa): Free it.
	* tree-dfa.c (remove_referenced_var): Clear the var from the
	call-used bitmap.

	* gcc.dg/tree-ssa/pr24287.c: Remove XFAIL.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@137222 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 38 insertions, 26 deletions

diff --git a/gcc/tree-ssa-operands.c b/gcc/tree-ssa-operands.c
index 71fb883f84a..0aeea9f7f93 100644
--- a/gcc/tree-ssa-operands.c
+++ b/gcc/tree-ssa-operands.c
@@ -1660,7 +1660,10 @@ add_call_clobber_ops (tree stmt, tree callee)
   bitmap_iterator bi;
   stmt_ann_t s_ann = stmt_ann (stmt);
   bitmap not_read_b, not_written_b;
-  
+  tree call = get_call_expr_in (stmt);
+
+  gcc_assert (!(call_expr_flags (call) & (ECF_PURE | ECF_CONST)));
+
   /* If we created .GLOBAL_VAR earlier, just use it.  */
   if (gimple_global_var (cfun))
     {
@@ -1674,12 +1677,10 @@ add_call_clobber_ops (tree stmt, tree callee)
      or write that variable.  */
   not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL; 
   not_written_b = callee ? ipa_reference_get_not_written_global (callee) : NULL; 
-
   /* Add a VDEF operand for every call clobbered variable.  */
   EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)
     {
       tree var = referenced_var_lookup (u);
-      unsigned int escape_mask = var_ann (var)->escape_mask;
       tree real_var = var;
       bool not_read;
       bool not_written;
@@ -1697,24 +1698,6 @@ add_call_clobber_ops (tree stmt, tree callee)
 
       /* See if this variable is really clobbered by this function.  */
 
-      /* Trivial case: Things escaping only to pure/const are not
-	 clobbered by non-pure-const, and only read by pure/const. */
-      if ((escape_mask & ~(ESCAPE_TO_PURE_CONST)) == 0)
-	{
-	  tree call = get_call_expr_in (stmt);
-	  if (call_expr_flags (call) & (ECF_CONST | ECF_PURE))
-	    {
-	      add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
-	      clobber_stats.unescapable_clobbers_avoided++;
-	      continue;
-	    }
-	  else
-	    {
-	      clobber_stats.unescapable_clobbers_avoided++;
-	      continue;
-	    }
-	}
-            
       if (not_written)
 	{
 	  clobber_stats.static_write_clobbers_avoided++;
@@ -1739,18 +1722,47 @@ add_call_read_ops (tree stmt, tree callee)
   bitmap_iterator bi;
   stmt_ann_t s_ann = stmt_ann (stmt);
   bitmap not_read_b;
+  tree call = get_call_expr_in (stmt);
+
+  /* Const functions do not reference memory.  */
+  if (call_expr_flags (call) & ECF_CONST)
+    return;
 
-  /* if the function is not pure, it may reference memory.  Add
-     a VUSE for .GLOBAL_VAR if it has been created.  See add_referenced_var
-     for the heuristic used to decide whether to create .GLOBAL_VAR.  */
+  not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL;
+
+  /* For pure functions we compute non-escaped uses separately.  */
+  if (call_expr_flags (call) & ECF_PURE)
+    EXECUTE_IF_SET_IN_BITMAP (gimple_call_used_vars (cfun), 0, u, bi)
+      {
+	tree var = referenced_var_lookup (u);
+	tree real_var = var;
+	bool not_read;
+
+	if (unmodifiable_var_p (var))
+	  continue;
+
+	not_read = not_read_b
+	    ? bitmap_bit_p (not_read_b, DECL_UID (real_var))
+	    : false;
+
+	clobber_stats.readonly_clobbers++;
+
+	/* See if this variable is really used by this function.  */
+	if (!not_read)
+	  add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
+	else
+	  clobber_stats.static_readonly_clobbers_avoided++;
+      }
+
+  /* Add a VUSE for .GLOBAL_VAR if it has been created.  See
+     add_referenced_var for the heuristic used to decide whether to
+     create .GLOBAL_VAR.  */
   if (gimple_global_var (cfun))
     {
       tree var = gimple_global_var (cfun);
       add_virtual_operand (var, s_ann, opf_use, NULL, 0, -1, true);
       return;
     }
-  
-  not_read_b = callee ? ipa_reference_get_not_read_global (callee) : NULL; 
 
   /* Add a VUSE for each call-clobbered variable.  */
   EXECUTE_IF_SET_IN_BITMAP (gimple_call_clobbered_vars (cfun), 0, u, bi)