Revert part of 2004-04-17 change that moved -frename-registers to -O1.

2004-04-19  Paolo Bonzini  <bonzini@gnu.org>

	Revert part of 2004-04-17 change that moved -frename-registers
	to -O1.  -frename-registers is buggy.

	* toplev.c (flag_rename_registers): Initialize to 0.
	* doc/invoke.texi (Optimize options): Move -frename-registers
	to "Not triggered by any -O level" section.  Adjust commentary
	accordingly.

From-SVN: r80887

gcc/ChangeLog

+2004-04-20  Paolo Bonzini  <bonzini@gnu.org>
+
+	Revert part of 2004-04-17 change that moved -frename-registers
+	to -O1.  -frename-registers is buggy.
+
+	* toplev.c (flag_rename_registers): Initialize to 0.
+	* doc/invoke.texi (Optimize options): Move -frename-registers
+	to "Not triggered by any -O level" section.  Adjust commentary
+	accordingly.
+					
 2004-04-20  Anil Paranjpe   <anilp1@kpitcummins.com>
 
 	* toplev.c (compile_file): Move targetm.asm_out.file_end call to end.

gcc/doc/invoke.texi

@@ -4342,19 +4342,6 @@ If @var{n} is not specified or is zero, use a machine-dependent default.
 
 Enabled at levels @option{-O2}, @option{-O3}.
 
-@item -frename-registers
-@opindex frename-registers
-Attempt to avoid false dependencies in scheduled code by making use
-of registers left over after register allocation.  This optimization
-will most benefit processors with lots of registers.  Depending on the
-debug information format adopted by the target, however, it can
-make debugging impossible, since variables will no longer stay in
-a ``home register''.
-
-Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os},
-on targets where the default format for debugging information supports
-variable tracking.
-
 @item -fweb
 @opindex fweb
 Constructs webs as commonly used for register allocation purposes and assign
@@ -4575,6 +4562,17 @@ using the knowledge about the value of the denominator.
 
 Enabled with @option{-profile-generate} and @option{-profile-use}.
 
+@item -frename-registers
+@opindex frename-registers
+Attempt to avoid false dependencies in scheduled code by making use
+of registers left over after register allocation.  This optimization
+will most benefit processors with lots of registers.  Depending on the
+debug information format adopted by the target, however, it can
+make debugging impossible, since variables will no longer stay in
+a ``home register''.
+
+Not enabled by default at any level because it has known bugs.
+
 @item -fnew-ra
 @opindex fnew-ra
 Use a graph coloring register allocator.  Currently this option is meant

gcc/toplev.c

@@ -268,8 +268,9 @@ int flag_reorder_functions = 0;
 
 /* Nonzero if registers should be renamed.  When
    flag_rename_registers == AUTODETECT_FLAG_VAR_TRACKING it will be set
-   according to optimize and default_debug_hooks in process_options ().  */
-int flag_rename_registers = AUTODETECT_FLAG_VAR_TRACKING;
+   according to optimize and default_debug_hooks in process_options (),
+   but we do not do this yet because it triggers aborts in flow.c.  */
+int flag_rename_registers = 0;
 int flag_cprop_registers = 0;
 
 /* Nonzero for -pedantic switch: warn about anything