invoke.texi (Optimize Options): Document that -funit-at-a-time is enabled at -O and above.

	* doc/invoke.texi (Optimize Options): Document that -funit-at-a-time
	is enabled at -O and above.

From-SVN: r114139

gcc/ChangeLog

-2006-05-24  Steven Bosscher  <steven@gcc.gnu.org>
+2006-05-26  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* doc/invoke.texi (Optimize Options): Document that -funit-at-a-time
+	is enabled at -O and above.
+
+2006-05-26  Steven Bosscher  <steven@gcc.gnu.org>
 
 	PR target/27571
 	* config/alpha/alpha.c (alpha_does_function_need_gp): Skip jump

gcc/doc/invoke.texi

@@ -4419,7 +4419,7 @@ the performance and/or code size at the expense of compilation time
 and possibly the ability to debug the program.
 
 The compiler performs optimization based on the knowledge it has of
-the program.  Optimization levels @option{-O2} and above, in
+the program.  Optimization levels @option{-O} and above, in
 particular, enable @emph{unit-at-a-time} mode, which allows the
 compiler to consider information gained from later functions in
 the file when compiling a function.  Compiling multiple files at
@@ -4459,6 +4459,7 @@ compilation time.
 -ftree-copyrename @gol
 -ftree-fre @gol
 -ftree-ch @gol
+-funit-at-a-time @gol
 -fmerge-constants}
 
 @option{-O} also turns on @option{-fomit-frame-pointer} on machines
@@ -4489,7 +4490,6 @@ also turns on the following optimization flags:
 -fstrict-aliasing @gol
 -fdelete-null-pointer-checks @gol
 -freorder-blocks  -freorder-functions @gol
--funit-at-a-time @gol
 -falign-functions  -falign-jumps @gol
 -falign-loops  -falign-labels @gol
 -ftree-vrp @gol
@@ -5422,7 +5422,7 @@ attribute @code{used} will prevent this behavior.
 As a temporary workaround, @option{-fno-unit-at-a-time} can be used,
 but this scheme may not be supported by future releases of GCC@.
 
-Enabled at levels @option{-O2}, @option{-O3}.
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
 
 @item -fno-toplevel-reorder
 Do not reorder top-level functions, variables, and @code{asm}