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variables v1,...,vn in v = phi(v1,...,vn) sometimes have null type although v has non-null type. #18

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
This happens very rarely.  I've observed it only for the method: 

dropTable:(Lorg/hsqldb/Session;Ljava/lang/String;Ljava/lang/String;ZZZ)V@org.hsq
ldb.SchemaManager

in the dacapo/hsqldb benchmark, for variable R23 in the following phi 
instruction:

98  PHI                     R35,    (R23, R28), { BB3, BB6 }

The problem seems to occur when there is a chain of PHIs.  The quadcode of this 
method is attached.  Currently, the workaround is to ignore variables like R23 
which have a null type from domain V, and to ignore assignments like from R23 
to R35 in constructing relation RelMobjVarAsgnInst.

Original issue reported on code.google.com by mayur.naik on 17 Jun 2010 at 5:21

Attachments:

GoogleCodeExporter commented 9 years ago 
fixed in revision r1003.  Variables with null type are now accepted into domain 
V (with type java.lang.Object), and so it is fine now to have such variables in 
Phi instructions.

Original comment by mayur.naik on 6 Aug 2010 at 4:06