[PATCH], Remove undocumented -mtoc-fusion from PowerPC

[Segher Boessenkool]

Hi Mike,

On Fri, Jul 13, 2018 at 04:56:13PM -0400, Michael Meissner wrote:
> This means rather than keeping the toc fusion around (that nobody used), I
> would prefer to delete the current code, and replace it with better code as I
> implement it.


> +++ gcc/config/rs6000/constraints.md	(working copy)

> +;; wG is now available.  Previously it was a memory operand suitable for TOC
> +;; fusion.

There are many other constraints unused.  Keep track of all, instead?
Like we have (at the top of this file)
;; Available constraint letters: e k q t u A B C D S T
you could do something similar for the "w" names.


> --- gcc/config/rs6000/predicates.md	(revision 262647)
> +++ gcc/config/rs6000/predicates.md	(working copy)
> @@ -412,7 +412,7 @@ (define_predicate "fpr_reg_operand"
>  ;;
>  ;; If this is a pseudo only allow for GPR fusion in power8.  If we have the
>  ;; power9 fusion allow the floating point types.
> -(define_predicate "toc_fusion_or_p9_reg_operand"
> +(define_predicate "p9_fusion_reg_operand"

The comment before this needs fixing, too:

;; Return true if this is a register that can has D-form addressing (GPR and
;; traditional FPR registers for scalars).  ISA 3.0 (power9) adds D-form
;; addressing for scalars in Altivec registers.
;;
;; If this is a pseudo only allow for GPR fusion in power8.  If we have the
;; power9 fusion allow the floating point types.

It's not clear to me what this really stands for (not before the patch,
either).


Okay for trunk.  Thanks!  Please follow up to the above two things.


Segher