Revert "PowerPC shrink-wrap support 3 of 3"

[Michael Meissner]

On Thu, Nov 10, 2011 at 02:29:04PM +0100, Bernd Schmidt wrote:
> On 11/10/11 13:14, Richard Guenther wrote:
> > Fair enough.  You can count me as "one" then, and I'll defer to Bernd
> > to either provide a fix or ack the revert.
> 
> I'm trying to track it down.
> 
> In 189r.outof_cfglayout, we have
> 
> (insn 31 33 35 3 (use (reg/i:SI 0 r0))
> ../../../../baseline-trunk/libstdc++-v3/libsupc++/new_opv.cc:34 -1
>      (nil))
> 
> ;; Successors:  EXIT [100.0%]  (fallthru)
> ;; lr  out       0 [r0] 11 [fp] 13 [sp] 14 [lr] 25 [sfp] 26 [afp]
> ;; live  out     0 [r0] 11 [fp] 13 [sp] 25 [sfp] 26 [afp]
> 
> followed by a number of other basic blocks, so that looks wrong to me.
> outof_cfglayout seems to assume that fallthrough edges to the exit block
> are OK and don't need fixing up, and changing that seems nontrivial at
> first glance.
> 
> The situation is first created during cfgcleanup in into_cfglayout. The
> following patch makes the testcase compile by stopping the compiler from
> moving the exit fallthru block around, but I've not checked whether it
> has a negative effect on code quality. HP, can you run full tests?

FWIW, I did bootstrap and make check with/without this patch, and it introduces
no regressions in the PowerPC, but I haven't look at the code generated.

-- 
Michael Meissner, IBM
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