[PATCH] Optimization docs part 5

[Jerry Quinn]

This is the last patch I have for the optimization docs.  It is a
cleanup of the text for the -O flag descriptions.

Geoff Keating okay'd the previous version in
http://gcc.gnu.org/ml/gcc-patches/2002-09/msg00955.html.  This version
is almost identical.  I just removed a redundant sentence.

Patch is against the 3.3 branch.

2002-12-17  Jerry Quinn  <jlquinn@optonline.net>

	* gcc/doc/invoke.texi (Optimization Options): Clean up -O flag
	  descriptions.

--- invoke.texi.p5	Tue Dec 17 01:50:40 2002
+++ invoke.texi	Tue Dec 17 02:14:03 2002
@@ -3388,7 +3388,22 @@
 @cindex optimize options
 @cindex options, optimization
 
-These options control various sorts of optimizations:
+These options control various sorts of optimizations.
+
+Without any optimization option, the compiler's goal is to reduce the
+cost of compilation and to make debugging produce the expected
+results.  Statements are independent: if you stop the program with a
+breakpoint between statements, you can then assign a new value to any
+variable or change the program counter to any other statement in the
+function and get exactly the results you would expect from the source
+code.
+
+Turning on optimization flags makes the compiler attempt to improve
+the performance and/or code size at the expense of compilation time
+and possibly the ability to debug the program.
+
+Not all optimizations are controlled directly by a flag.  Only
+optimizations that have a flag are listed.
 
 @table @gcctabopt
 @item -O
@@ -3398,13 +3413,6 @@
 Optimize.  Optimizing compilation takes somewhat more time, and a lot
 more memory for a large function.
 
-Without @option{-O}, the compiler's goal is to reduce the cost of
-compilation and to make debugging produce the expected results.
-Statements are independent: if you stop the program with a breakpoint
-between statements, you can then assign a new value to any variable or
-change the program counter to any other statement in the function and
-get exactly the results you would expect from the source code.
-
 With @option{-O}, the compiler tries to reduce code size and execution
 time, without performing any optimizations that take a great deal of
 compilation time.
@@ -3481,10 +3489,15 @@
 
 Options of the form @option{-f@var{flag}} specify machine-independent
 flags.  Most flags have both positive and negative forms; the negative
-form of @option{-ffoo} would be @option{-fno-foo}.  In the table below,
-only one of the forms is listed---the one which is not the default.
-You can figure out the other form by either removing @samp{no-} or
-adding it.
+form of @option{-ffoo} would be @option{-fno-foo}.  In the table
+below, only one of the forms is listed---the one you typically will
+use.  You can figure out the other form by either removing @samp{no-}
+or adding it.
+
+The following options control specific optimizations.  They are either
+activated by @option{-O} options or are related to ones that are.  You
+can use the following flags in the rare cases when ``fine-tuning'' of
+optimizations to be performed is desired.
 
 @table @gcctabopt
 @item -fno-default-inline
@@ -3651,21 +3664,6 @@
 
 The default is @option{-fzero-initialized-in-bss}.
 
-@end table
-
-The following options control specific optimizations.  The @option{-O2}
-option turns on all of these optimizations except @option{-funroll-loops}
-and @option{-funroll-all-loops}.  On most machines, the @option{-O} option
-turns on the @option{-fthread-jumps} and @option{-fdelayed-branch} options,
-but specific machines may handle it differently.
-
-You can use the following flags in the rare cases when ``fine-tuning''
-of optimizations to be performed is desired.
-
-Not all of the optimizations performed by GCC have @option{-f} options
-to control them.
-
-@table @gcctabopt
 @item -fstrength-reduce
 @opindex fstrength-reduce
 Perform the optimizations of loop strength reduction and