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Re: Why can't CSE recognize const_int's in HIGH LO_SUM pair?
- To: Richard Henderson <rth at redhat dot com>, law at redhat dot com, John David Anglin <dave at hiauly1 dot hia dot nrc dot ca>, Bernd Schmidt <bernds at redhat dot com>, gcc at gcc dot gnu dot org
- Subject: Re: Why can't CSE recognize const_int's in HIGH LO_SUM pair?
- From: David Edelsohn <dje at watson dot ibm dot com>
- Date: Mon, 10 Sep 2001 13:04:05 -0400
>>>>> Richard Henderson writes:
Richard> The thing I like about exposing the split early is that
Richard> gcse gets to move these expressions around. If you expose
Richard> the split later, nothing is going to move the parts around
Richard> as aggressively.
However, splitting the constant early inhibits other optimizations
in GCC which do not see the entire constant. Additionally, other parts of
GCC do not try to synthesize the larger constants internally if patterns
don't accept the full constant range.
David