re PR target/36713 (r137252 breaks -O2 optimization on x86_64-unknown-linux-gnu)

2008-07-07  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/36713
	* tree-flow-inline.h (is_call_used): New function.
	* tree-nrv.c (dest_safe_for_nrv_p): Use it.
	* tree-tailcall.c (suitable_for_tail_opt_p): Likewise.
	* tree-outof-ssa.c (create_temp): Set call-used flag if required.

From-SVN: r137571

gcc/ChangeLog

+2008-07-07  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/36713
+	* tree-flow-inline.h (is_call_used): New function.
+	* tree-nrv.c (dest_safe_for_nrv_p): Use it.
+	* tree-tailcall.c (suitable_for_tail_opt_p): Likewise.
+	* tree-outof-ssa.c (create_temp): Set call-used flag if required.
+
 2008-07-07  Maxim Kuvyrkov  <maxim@codesourcery.com>
 
 	* config/m68k/m68k.c (m68k_return_in_memory): Fix arguments types.

gcc/tree-flow-inline.h

@@ -881,7 +881,15 @@ factoring_name_p (const_tree name)
   return TREE_CODE (SSA_NAME_VAR (name)) == MEMORY_PARTITION_TAG;
 }
 
-/* Return true if VAR is a clobbered by function calls.  */
+/* Return true if VAR is used by function calls.  */
+static inline bool
+is_call_used (const_tree var)
+{
+  return (var_ann (var)->call_clobbered
+	  || bitmap_bit_p (gimple_call_used_vars (cfun), DECL_UID (var)));
+}
+
+/* Return true if VAR is clobbered by function calls.  */
 static inline bool
 is_call_clobbered (const_tree var)
 {

gcc/tree-nrv.c

@@ -265,7 +265,7 @@ dest_safe_for_nrv_p (tree dest)
   if (TREE_CODE (dest) == SSA_NAME)
     dest = SSA_NAME_VAR (dest);
 
-  if (is_call_clobbered (dest))
+  if (is_call_used (dest))
     return false;
 
   return true;

gcc/tree-outof-ssa.c

@@ -128,6 +128,8 @@ create_temp (tree t)
   set_symbol_mem_tag (tmp, symbol_mem_tag (t));
   if (is_call_clobbered (t))
     mark_call_clobbered (tmp, var_ann (t)->escape_mask);
+  if (bitmap_bit_p (gimple_call_used_vars (cfun), DECL_UID (t)))
+    bitmap_set_bit (gimple_call_used_vars (cfun), DECL_UID (tmp));
 
   return tmp;
 }

gcc/tree-tailcall.c

@@ -138,14 +138,14 @@ suitable_for_tail_opt_p (void)
   if (cfun->stdarg)
     return false;
 
-  /* No local variable nor structure field should be call-clobbered.  We
+  /* No local variable nor structure field should be call-used.  We
      ignore any kind of memory tag, as these are not real variables.  */
 
   FOR_EACH_REFERENCED_VAR (var, rvi)
     {
       if (!is_global_var (var)
 	  && !MTAG_P (var)
-	  && (gimple_aliases_computed_p (cfun) ? is_call_clobbered (var)
+	  && (gimple_aliases_computed_p (cfun)? is_call_used (var)
 	      : TREE_ADDRESSABLE (var)))
 	return false;
     }