On Sun, 19 Oct 2014, Marc Glisse wrote: > Hello, > > looking though the patterns on the branch (not specifically the ones attached > here), I am surprised to see so few calls to has_single_use. In RTL-land, we > don't even valueize if there are several uses, so the question doesn't occur. > In generic, we assume everything is single use (CSE could later disagree, but > that's the user's fault for writing his code that way). In > tree-ssa-forwprop.c, helpers like get_prop_source_stmt do test for single use. > Since has_single_use is a bit painful to use in .pd files (separate test for > generic and constants), it might deserve another helper function, or a special > syntax.
But I don't think "has_single_use" is a good tool to disable transforms on. It's also used very inconsistently in tree-ssa-forwprop.c. See also my other mail. Richard.
