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
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