[patch] New backend header reduction

[Jeff Law]

On 10/23/2015 10:53 AM, Andrew MacLeod wrote:
> Just finished running...  I think the external hard drive was slowing
> down this run :-P  It took quite a while.
>
> Anyway, this is the reduction patch independent of the header-ordering
> patch... ie, that patch needs to be applied before this one.   So this
> should be mostly just removals.   I also need to follow up and build all
> the target and bootstrap from scratch to make sure there arent any
> weirdnesses with it.   But you can at least get a look at it now.
>
> a few interesting stats:
>
> Top reductions:
>
> passes.c: Reduction performed, 26 includes removed.
> shrink-wrap.c: Reduction performed, 21 includes removed.
> ipa-polymorphic-call.c: Reduction performed, 21 includes removed.
> lto-cgraph.c: Reduction performed, 19 includes removed.
> ddg.c: Reduction performed, 19 includes removed.
> tree-ssa-pre.c: Reduction performed, 18 includes removed.
> lra-remat.c: Reduction performed, 18 includes removed.
> cgraph.c: Reduction performed, 18 includes removed.
> cgraphclones.c: Reduction performed, 18 includes removed.
> tsan.c: Reduction performed, 17 includes removed.
> tree-into-ssa.c: Reduction performed, 17 includes removed.
> lto-section-in.c: Reduction performed, 17 includes removed.
>
> And headers most often removed:
>
> alias.h: Removed 230 times.
> flags.h: Removed 207 times.
> internal-fn.h: Removed 143 times.
> stmt.h: Removed 128 times.
> dojump.h: Removed 122 times.
> expmed.h: Removed 115 times.
> explow.h: Removed 115 times.
> varasm.h: Removed 114 times.
> calls.h: Removed 114 times.
> expr.h: Removed 81 times.
> insn-config.h: Removed 77 times.
> emit-rtl.h: Removed 62 times.
> hard-reg-set.h: Removed 60 times.
> tm_p.h: Removed 56 times.
> fold-const.h: Removed 56 times.
> diagnostic-core.h: Removed 53 times.
> except.h: Removed 51 times.
Approved.  This was the easy part :-)

A quick grep shows 2309 unnecessary #includes removed.

jeff