[RFC] New intermediate languages

[Michael Matz]

Hi,

On Thu, 1 Feb 2001, Diego Novillo wrote:

> These are some of the general properties of MRTL.
> 
> - Control flow representation is similar to RTL. No structured
>   control-flow, everything is represented with jumps and
>   compare/branch.

Much of the inhomogenity and constrains of RTL should be removed here.
E.g. requiring a CC-setter to be one before the CC-user, may be even get
rid of both, introducing a new CODE containing both an boolean expression,
and the instruction. Removing PARALLEL alltogether by making it possible
to have many operations per INSN. Shortening of RTL expressions only
stating properties of contained elements (I think here of ZERO_EXTRACT,
SUBREG, STRICT_LOW_PART) by replacing them with attributes to the targets
(e.g. like (REG 32 <sub 0, strict_low>) ) as many of the loops dealing
with RTL do nothing more than reading over them to get hold of the regno
(e.g.). Get rid of freaking BASIC_BLOCK_NODES. Group all MRTL-INSN into
basic blocks, and make _that_ the main view on them (only optionally go
through INSN-chains crossing block boudaries). Make jump target's not
labels, but basic block numbers.

Such things, and more I can't currently think of ;)


Ciao,
Michael.