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Re: Possible CSE quirk involving SUBREG on the i386
- To: john at feith dot com (John Wehle)
- Subject: Re: Possible CSE quirk involving SUBREG on the i386
- From: Jeffrey A Law <law at cygnus dot com>
- Date: Tue, 30 Jun 1998 15:04:46 -0600
- cc: egcs at cygnus dot com
- Reply-To: law at cygnus dot com
> It appears that CSE changed (reg/v:HI 23) in insn 16 to
> (subreg:HI (reg:SI 22) 0) yet it did not perform this
> same substitution in insn 18. I would have expected
> the same substitution in both places.
In that case, you might see if it was rejected because the perceived
cost wasn't worth the benefit. It may also be the case that the
zero_extendhisi pattern won't accept a subreg. I haven't looked.
jeff