+2001-07-05 Brad Lucier <lucier@math.purdue.edu>
+ Gerald Pfeifer <pfeifer@dbai.tuwien.ac.at>
+
+ * doc/invoke.texi (Optimize Options): Document that -fgcse may
+ cause programs using computed gotos to run more slowly.
+
2001-07-05 Rainer Orth <ro@TechFak.Uni-Bielefeld.DE>
* doc/install.texi (Specific): Markup, spelling and typo fixes.
@option{-fforce-mem} option on all machines and frame pointer elimination
on machines where doing so does not interfere with debugging.
+Please note the warning under @option{-fgcse} about
+invoking @option{-O2} on programs that use computed gotos.
+
@item -O3
@opindex O3
Optimize yet more. @option{-O3} turns on all optimizations specified by
Perform a global common subexpression elimination pass.
This pass also performs global constant and copy propagation.
+@emph{Note:} When compiling a program using computed gotos, a GCC
+extension, you may get better runtime performance if you disable
+the global common subexpression elmination pass by adding
+@option{-fno-gcse} to the command line.
+
@item -fgcse-lm
@opindex fgcse-lm
When @option{-fgcse-lm} is enabled, global common subexpression elimination will