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Re: [RFC] Contributing tree-ssa to mainline
- From: law at redhat dot com
- To: Robert Dewar <dewar at gnat dot com>
- Cc: Jan Hubicka <hubicka at ucw dot cz>, Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>, gcc at gcc dot gnu dot org
- Date: Mon, 19 Jan 2004 10:46:04 -0700
- Subject: Re: [RFC] Contributing tree-ssa to mainline
- Reply-to: law at redhat dot com
In message <400C142A.6010205@gnat.com>, Robert Dewar writes:
>> >However Ada is not the only language having checks. In some extend,
>> >Java has the array bounds too. If the value range propagation pass were
>> >available, Java would take benefit of it too.
>> And C/C++ when instrumented to detect invalid memory operations.
>>
>> jeff
>
>Certainly Ada would benefit from such a pass. Right now, the front end
>of Ada does a lot of work on computing value ranges, but it does a poor
>job of propagation, since we have not put any kind of non-trivial flow
>graph propagation into the front end.
FWIW, the plan is to use the CCP engine for global value range propagation
(and other stuff like global null pointer check elimination). The biggest
blocker is simply time to generalize the existing CCP code so that it can
do something other than propagate simple constants. Using a CCP engine
for these optimizations is well understood technology.
jeff