http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52838
Uros Bizjak <ubizjak at gmail dot com> changed:
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CC| |ubizjak at gmail dot com
--- Comment #4 from Uros Bizjak <ubizjak at gmail dot com> 2012-04-05 12:36:28
UTC ---
(In reply to comment #2)
> The existence of (subreg/s/u:SI (reg:DI 60) 0) means that (reg:DI 60) is known
> to be a zero-extended 32-bit value, so the optimization is valid (and useful).
Please note similar problem with sign_extend, PR 52876.
