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Re: try_split lossage
- To: John Wehle <john at feith dot com>
- Subject: Re: try_split lossage
- From: Jeffrey A Law <law at cygnus dot com>
- Date: Wed, 04 Aug 1999 01:19:15 -0600
- cc: egcs at egcs dot cygnus dot com
- Reply-To: law at cygnus dot com
In message <199906161751.NAA13265@jwlab.FEITH.COM>you write:
> An insn may have various characteristics (such as CONST_CALL_P,
> INSN_ANNULLED_BRANCH_P, INSN_FROM_TARGET_P, RTX_FRAME_RELATED_P)
> which affect code generation. try_split attempts to replace the
> insn with other insn(s). What isn't clear to me is how the new
> insn(s) inherit the characteristics of the insn which is being
> replaced.
>
> Should try_split either abort or avoid splitting insns which
> have any of these characteristics?
Well, losing a CONST_CALL_P or RTX_FRAME_RELATED_P shouldn't cause any serious
problems.
However, losing the ANNULLED_BRANCH_P or INSN_FROM_TARGET_P could cause
problems. But we shouldn't get insns with those bits set because they
would have already been split by the delay slot scheduler.
jeff