------- Comment #5 from aldot at gcc dot gnu dot org 2007-12-30 10:47 ------- Created an attachment (id=14842) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14842&action=view) rough, half-finished, disfunctional thought; not a patch
The attached thoughts do not yet insert/remove stmt candidates but just record possible candidates in the corresponding bitmaps. Unfortunately this prooves that the current SSA-SCCN-VN does not work for the testcase in comment #1 since antic_in is empty (but it should contain ++i). Nevertheless this will potentially help for PR23286 and PR5738 since for those testcases the hoisting-candidates are found properly. I intend to think about finishing this draft as described by stevenb soonish but still, i will have to finish up the inefficient variant that only cares about switch stmts (perhaps defaulting to on at -Os, just for my personal use) until SSA-SCCN-VN recognizes the VN for the testcase of #1 -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11832
