Question about cfgrtl.c:flow_delete_block_noexpunge

[Richard Earnshaw]

> On Tue, Jun 10, 2003 at 08:41:32PM -0600, law@redhat.com wrote:
> > Kenner -- if you really want to fix this problem, attach the jump table
> > to the tablejump/switch insn itself.  Doing that would enable cleanups
> > in several places within the compiler.
> 
> Given my druthers, I wouldn't do that either.  I'd have the
> jump tables in a data structure external to the insn stream.
> 
> Consider that with the single exception of VAX and its funny
> casesi instruction, there is no architecture that absolutely
> requires the table to be adjacent to the jump insn (there are
> several that benefit from it, like arm, m68k, sh, but...).
> Keeping the table external means that we can solve problems
> related to basic block replication in trace scheduling and
> the like.

There are other problems with the case tables at present as well.  I'd 
really like to put compressed tables out-of-line for some ARM 
compilations; but in order to do that I need the address of dispatch 
instruction in addition to the address of the table.  Currently GCC only 
holds the latter and there's no way to get the former when emitting the 
table.

R.