On Fri, 2005-11-11 at 22:53 -0800, Ian Lance Taylor wrote: > David Daney <[EMAIL PROTECTED]> writes: > > > > Eventually we should manually mark certain function DECLs as > > > not-returning-null instead of my kludgy test for this one case. I don't > > > know if/when I can get to that. Perhaps somebody else can take it from > > > here. > > > > Looks like all the bits in struct tree_common are used up. > > > > Q: Would it make sense to add a flag to struct tree_decl_common to > > indicate !zero, set it using an attribute, (and automatically in the > > java front-end for the cases above), and then test for it in > > tree-vrp.c similar to below? > > This should be done using an attribute, yes. If this is going to be > tested frequently enough, it would make sense to add a bit to struct > tree_function_decl (I don't see any reason to put it in struct > tree_decl-common) (there is currently room for one more bit in > tree_function_decl on a machine which requires 16-bit alignment, or 17 > more bits on a machine which requires 32-bit alignment).
Note you could also put things in decl_non_common, but i'd probably beat you up :) > Note that it > is also possible to simply store the attribute on DECL_ATTRIBUTES and > look it up using lookup_attribute. IMHO, this is the way to go. The number of times we look at attributes on function_decls (IE through call_expr_flags, etc) is so small i've never understood why we use so many bits to represent thing we are getting from attributes. Most functions have no attributes, so it's a very simple check for lookup_attribute to perform. Even when they have *1* attribute, it's still simple. > > Ian
