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Re: [RFC][PR middle-end/59285] builtin-unreachable-6 on ARM


On 26 November 2013 22:05, Jeff Law <law@redhat.com> wrote:

> Open to other suggestions.  The fundamental issue is BARRIERs live outside
> the CFG.  So a pass that thinks it can manipulate the CFG and ignore the
> underlying RTL are going to have problems with things like this.

Here, the barrier itself acts like a JUMP_INSN with a special target -
a bit like return, except that our special destination here is
'unreachable'.

If you want to express this in the cfg other than having no successors, you
should have a special UNREACHABLE block, which thus becomes competition
for the exit block.


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