invoke.texi: Document -Ofast.

2010-05-25  Richard Guenther  <rguenther@suse.de>

	* doc/invoke.texi: Document -Ofast.
	* target.h (struct gcc_target): Add handle_ofast.
	* target-def.h (TARGET_HANDLE_OFAST): Add.
	(TARGET_INITIALIZER): Adjust.
	* opts.c (decode_options): Handle -Ofast.  Enable
	-ffast-math with it.
	* common.opt (Ofast): Add.

From-SVN: r159815

gcc/ChangeLog

@@ -1,3 +1,13 @@
+2010-05-25  Richard Guenther  <rguenther@suse.de>
+
+	* doc/invoke.texi: Document -Ofast.
+	* target.h (struct gcc_target): Add handle_ofast.
+	* target-def.h (TARGET_HANDLE_OFAST): Add.
+	(TARGET_INITIALIZER): Adjust.
+	* opts.c (decode_options): Handle -Ofast.  Enable
+	-ffast-math with it.
+	* common.opt (Ofast): Add.
+
 2010-05-25  Paolo Bonzini  <bonzini@gnu.org>
 
 	* doc/tm.texi (STORE_FLAG_VALUE): Do not refer to sCC patterns.

gcc/common.opt

@@ -69,6 +69,10 @@ Os
 Common Optimization
 Optimize for space rather than speed
 
+Ofast
+Common Optimization
+Optimize for speed disregarding exact standards compliance
+
 W
 Common RejectNegative Var(extra_warnings) Warning
 This switch is deprecated; use -Wextra instead

gcc/doc/invoke.texi

@@ -393,7 +393,7 @@ Objective-C and Objective-C++ Dialects}.
 -fvariable-expansion-in-unroller -fvect-cost-model -fvpt -fweb @gol
 -fwhole-program -fwhopr[=@var{n}] -fwpa -fuse-linker-plugin @gol
 --param @var{name}=@var{value}
--O  -O0  -O1  -O2  -O3  -Os}
+-O  -O0  -O1  -O2  -O3  -Os -Ofast}
 
 @item Preprocessor Options
 @xref{Preprocessor Options,,Options Controlling the Preprocessor}.
@@ -5891,6 +5891,13 @@ optimizations designed to reduce code size.
 -falign-labels  -freorder-blocks  -freorder-blocks-and-partition @gol
 -fprefetch-loop-arrays  -ftree-vect-loop-version}
 
+@item -Ofast
+@opindex Ofast
+Disregard strict standards compliance.  @option{-Ofast} enables all
+@option{-O3} optimizations.  It also enables optimizations that are not
+valid for all standard compliant programs.
+It turns on @option{-ffast-math}.
+
 If you use multiple @option{-O} options, with or without level numbers,
 the last such option is the one that is effective.
 @end table

gcc/opts.c

@@ -63,7 +63,7 @@ bool warn_larger_than;
 HOST_WIDE_INT larger_than_size;
 
 /* True to warn about any function whose frame size is larger
- * than N bytes. */
+   than N bytes. */
 bool warn_frame_larger_than;
 HOST_WIDE_INT frame_larger_than_size;
 
@@ -804,6 +804,7 @@ decode_options (unsigned int argc, const char **argv)
   int opt2;
   int opt3;
   int opt1_max;
+  int ofast = 0;
 
   if (first_time_p)
     {
@@ -831,6 +832,7 @@ decode_options (unsigned int argc, const char **argv)
 	{
 	  optimize = 1;
 	  optimize_size = 0;
+	  ofast = 0;
 	}
       else if (argv[i][0] == '-' && argv[i][1] == 'O')
 	{
@@ -843,6 +845,14 @@ decode_options (unsigned int argc, const char **argv)
 
 	      /* Optimizing for size forces optimize to be 2.  */
 	      optimize = 2;
+	      ofast = 0;
+	    }
+	  else if (strcmp (p, "fast") == 0)
+	    {
+	      /* -Ofast only adds flags to -O3.  */
+	      optimize_size = 0;
+	      optimize = 3;
+	      ofast = 1;
 	    }
 	  else
 	    {
@@ -853,6 +863,7 @@ decode_options (unsigned int argc, const char **argv)
 		  if ((unsigned int) optimize > 255)
 		    optimize = 255;
 		  optimize_size = 0;
+		  ofast = 0;
 		}
 	    }
 	}
@@ -967,6 +978,17 @@ decode_options (unsigned int argc, const char **argv)
   else
     set_param_value ("min-crossjump-insns", initial_min_crossjump_insns);
 
+  /* -Ofast adds optimizations to -O3.  */
+  if (ofast)
+    {
+      /* Which is -ffast-math for now.  */
+      set_fast_math_flags (1);
+      /* Allow targets to enable extra options with -Ofast
+	 before general options processing so disabling them
+	 again afterwards works.  */
+      targetm.handle_ofast ();
+    }
+
   /* Enable -Werror=coverage-mismatch by default */
   enable_warning_as_error("coverage-mismatch", 1, lang_mask);
 

gcc/target-def.h

@@ -431,6 +431,7 @@
 #define TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE hook_void_void
 
 #define TARGET_HANDLE_OPTION hook_bool_size_t_constcharptr_int_true
+#define TARGET_HANDLE_OFAST hook_void_void
 #define TARGET_HELP NULL
 
 /* In except.c */
@@ -939,6 +940,7 @@
   TARGET_DEFAULT_TARGET_FLAGS,			\
   TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE,		\
   TARGET_HANDLE_OPTION,				\
+  TARGET_HANDLE_OFAST,				\
   TARGET_HELP,					\
   TARGET_EH_RETURN_FILTER_MODE,			\
   TARGET_LIBGCC_CMP_RETURN_MODE,                \

gcc/target.h

@@ -531,6 +531,9 @@ struct gcc_target
      form was.  Return true if the switch was valid.  */
   bool (* handle_option) (size_t code, const char *arg, int value);
 
+  /* Handle target-specific parts of specifying -Ofast.  */
+  void (* handle_ofast) (void);
+
   /* Display extra, target specific information in response to a
      --target-help switch.  */
   void (* target_help) (void);