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From: "rth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/46219] Generate indirect jump instruction on x86-64
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46219

Richard Henderson <rth at gcc dot gnu.org> changed:

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--- Comment #3 from Richard Henderson <rth at gcc dot gnu.org> 2010-10-29 16:45:47 UTC ---
That would be because we have no good way to say: global memory is fine,
but the on-stack memory that we just deallocated is not.

In addition for this case, we have to ensure that the registers used to
do the indexing are still valid after call-saved registers have been
restored, and avoid any call-clobbered registers that might be needed
to execute the epilogue.

In general I don't think this is solvable, but for this specific case
we could add a peephole.