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Re: Why does GCJ generate so many explicit checks for null pointers?

From: Andrew Haley <aph at redhat dot com>
To: Jeff Sturm <jsturm at one-point dot com>
Cc: David Daney <ddaney at avtrex dot com>, tromey at redhat dot com, <java at gcc dot gnu dot org>
Date: Tue, 29 Jul 2003 11:34:48 +0100
Subject: Re: Why does GCJ generate so many explicit checks for null pointers?
References: <3F25591E.3040003@avtrex.com><Pine.LNX.4.44.0307290114520.32300-100000@ops2.one-point.com>

Jeff Sturm writes:
 > On Mon, 28 Jul 2003, David Daney wrote:
 > > Why check before the constructor call?  Is it ever possible for
 > > _Jv_AllocObjectNoFinalizer to return null?
 > 
 > No, but the backend optimizers don't know that, or else DCE would
 > eliminate the test.

 > Currently only a few java-specific optimizations are done by gcj.

Null pointer check elimination isn't really Java specific.  

The plan is to do this optimization in tree-SSA.  With that framework
it isn't very difficult.

Andrew.

Follow-Ups:
- Re: Why does GCJ generate so many explicit checks for null pointers?
  - From: Jeff Sturm

References:
- Re: Why does GCJ generate so many explicit checks for null pointers?
  - From: David Daney
- Re: Why does GCJ generate so many explicit checks for null pointers?
  - From: Jeff Sturm

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