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Re: literal pool support
- To: Richard Henderson <rth at cygnus dot com>
- Subject: Re: literal pool support
- From: David Edelsohn <dje at watson dot ibm dot com>
- Date: Wed, 07 Jul 1999 18:22:52 -0400
- Cc: linas at linas dot org, egcs-patches at egcs dot cygnus dot com
>>>>> Richard Henderson writes:
Richard> On Wed, Jul 07, 1999 at 05:27:49PM -0400, David Edelsohn wrote:
>> Is there a good reason why a compiler should be relying on a
>> literal pool located in the code segment at all?
Richard> Branch addresses are formed like memory addresses. So you need
Richard> some sort of pointer within code already.
I am not sure what you mean by this. Yes, one needs a base
register for branches, but one need not create a literal pool which must
be addressed by that base register. One needs local addressibility for
branches, but one does not need a literal pool.
If one did not generate a literal pool then one would not need to
keep track of the size of a literal pool in addition to the normal length
attribute. The choice of branch instructions would be based solely on
instruction length using the normal shorten_branches() optimization
without any modification and without creating an additional "length"-like
attribute.
David