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Re: [PATCH] PR optimization/11741: PRE multiple sets in a PARALLEL
- From: Richard Henderson <rth at redhat dot com>
- To: Roger Sayle <roger at eyesopen dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Wed, 3 Sep 2003 17:12:16 -0700
- Subject: Re: [PATCH] PR optimization/11741: PRE multiple sets in a PARALLEL
- References: <Pine.LNX.4.44.0309021503420.4821-100000@www.eyesopen.com>
On Tue, Sep 02, 2003 at 04:15:04PM -0600, Roger Sayle wrote:
> Unfortunately there's a mismatch. The code in hash_scan_insn that
> places available expressions in the expr hash table is happy to deal
> with parallels containg multiple sets.
This is the bug, because the code in the middle that does
the LCM isn't happy to deal with this. Indeed, afaik it'll
treat the two expressions separately, and may decide to put
them in different places. Which is not cool.
Thus changing pre_insert_copy_insn is exactly wrong.
r~