flags.h (flag_optimize_sibling_calls): Declare.

* flags.h (flag_optimize_sibling_calls): Declare.
	* calls.c (expand_call): Fail sibcall when
	!flag_optimize_sibling_calls
	* invoke.texi (flag_optimize_sibling_calls): Document.
	* toplev.c (flag_optimize_sibling_calls): New global variable.
	(f_options): Add flag_optimize_sibling_calls.
	(rest_of_compilation): Conditionize
	optimize_sibling_and_tail_recursive_calls by
	flag_optimize_sibling_calls.
	(main): Set flag_optimize_sibling_calls for -O2.
	* stmt.c (expand_return): Conditionize tail recursion by
	flag_optimize_sibling_calls.

From-SVN: r32802

gcc/ChangeLog

@@ -1,3 +1,18 @@
+Wed Mar 29 11:51:13 MET DST 2000  Jan Hubicka  <jh@suse.cz>
+
+	* flags.h (flag_optimize_sibling_calls): Declare.
+	* calls.c (expand_call): Fail sibcall when
+	!flag_optimize_sibling_calls
+	* invoke.texi (flag_optimize_sibling_calls): Document.
+	* toplev.c (flag_optimize_sibling_calls): New global variable.
+	(f_options): Add flag_optimize_sibling_calls.
+	(rest_of_compilation): Conditionize
+	optimize_sibling_and_tail_recursive_calls by
+	flag_optimize_sibling_calls.
+	(main): Set flag_optimize_sibling_calls for -O2.
+	* stmt.c (expand_return): Conditionize tail recursion by
+	flag_optimize_sibling_calls.
+
 2000-03-29  Richard Henderson  <rth@cygnus.com>
 
 	* config/i386/att.h (LOCAL_LABEL_PREFIX): Define.

gcc/calls.c

@@ -2034,7 +2034,7 @@ expand_call (exp, target, ignore)
      the call.  */
 
   try_tail_call = 0;
-  if (optimize >= 2
+  if (flag_optimize_sibling_calls
       && currently_expanding_call == 1
       && stmt_loop_nest_empty ()
       && ! any_pending_cleanups (1))

gcc/flags.h

@@ -299,6 +299,10 @@ extern int flag_volatile_static;
 
 extern int flag_fast_math;
 
+/* Nonzero allows GCC to optimize sibling and tail recursive calls.  */
+
+extern int flag_optimize_sibling_calls;
+
 /* Nonzero means the front end generally wants `errno' maintained by math
    operations, like built-in SQRT, unless overridden by flag_fast_math.  */
 

gcc/invoke.texi

@@ -164,8 +164,8 @@ in the following sections.
 -finline-functions  -finline-limit=@var{n}  -fkeep-inline-functions
 -fmove-all-movables  -fno-default-inline  -fno-defer-pop
 -fno-function-cse  -fno-inline  -fno-peephole
--fomit-frame-pointer  -foptimize-register-moves  -fregmove
--frerun-cse-after-loop  -frerun-loop-opt  -freduce-all-givs
+-fomit-frame-pointer  -foptimize-register-moves -foptimize-sibling-calls
+-fregmove -frerun-cse-after-loop  -frerun-loop-opt  -freduce-all-givs
 -fschedule-insns  -fschedule-insns2  -fstrength-reduce
 -fstrict-aliasing  -fthread-jumps  -funroll-all-loops
 -funroll-loops
@@ -2461,6 +2461,9 @@ restore frame pointers; it also makes an extra register available
 in many functions.  @strong{It also makes debugging impossible on
 some machines.}
 
+@item -foptimize-sibling-calls
+Optimize sibling and tail recursive calls.
+
 @ifset INTERNALS
 On some machines, such as the Vax, this flag has no effect, because
 the standard calling sequence automatically handles the frame pointer

gcc/stmt.c

@@ -2872,7 +2872,7 @@ expand_return (retval)
     }
 
   /* Attempt to optimize the call if it is tail recursive.  */
-  if (optimize
+  if (flag_optimize_sibling_calls
       && retval_rhs != NULL_TREE
       && frame_offset == 0
       && TREE_CODE (retval_rhs) == CALL_EXPR

gcc/toplev.c

@@ -519,6 +519,10 @@ int flag_no_peephole = 0;
 
 int flag_fast_math = 0;
 
+/* Nonzero allows GCC to optimize sibling and tail recursive calls.  */
+
+int flag_optimize_sibling_calls = 0;
+
 /* Nonzero means the front end generally wants `errno' maintained by math
    operations, like built-in SQRT, unless overridden by flag_fast_math.  */
 
@@ -863,6 +867,8 @@ lang_independent_options f_options[] =
    "Defer popping functions args from stack until later" },
   {"omit-frame-pointer", &flag_omit_frame_pointer, 1,
    "When possible do not generate stack frames"},
+  {"optimize-sibling-calls", &flag_optimize_sibling_calls, 1,
+   "Optimize sibling and tail recursive calls" },
   {"cse-follow-jumps", &flag_cse_follow_jumps, 1,
    "When running CSE, follow jumps to their targets" },
   {"cse-skip-blocks", &flag_cse_skip_blocks, 1,
@@ -2991,7 +2997,7 @@ rest_of_compilation (decl)
   /* We may have potential sibling or tail recursion sites.  Select one
      (of possibly multiple) methods of performing the call.  */
   init_EXPR_INSN_LIST_cache ();
-  if (optimize)
+  if (flag_optimize_sibling_calls)
     optimize_sibling_and_tail_recursive_calls ();
   
   if (ggc_p)
@@ -4733,6 +4739,7 @@ main (argc, argv)
 
   if (optimize >= 2)
     {
+      flag_optimize_sibling_calls = 1;
       flag_cse_follow_jumps = 1;
       flag_cse_skip_blocks = 1;
       flag_gcse = 1;