About the is_gimple_min_invariant predicate

Richard Kenner kenner@vlsi1.ultra.nyu.edu
Thu Jul 5 12:32:00 GMT 2007


> Can you please, again,  explain why we even have this wasting space in
> all the component_ref's?
> 
> tree.def simply says "  Operand 2, if present, is the value of
> DECL_FIELD_OFFSET, measured
>    in units of DECL_OFFSET_ALIGN / BITS_PER_UNIT."
> 
> It doesn't say why this can't be computed on the fly and have 1 bit
> that says whether we need to use that value or not.

Same reason as the lower bound and size in an ARRAY_REF: it might be
a function of the value of a field in the record, so could be
different for every access (discriminated records in Ada).



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