I seem to be having a problem with the pre pass. When eliminate_dom_walker::eliminate_stmt is called with the gsi to "dedangled_864 = bea_43->tail;" which in turn calls eliminate_dom_walker::eliminate_avail op of dedangled_864. This gives VN_INFO (lhs)->valnum of _920. The _920 is not associated with any SSA variable in the function and I don't see how it got associated with dedangled_864. This is not a theoretical issue because it causes an error (the gcc_unreachable in eliminate_stmt is called.)
Here is how _920 (in function main) is used. _920 = arcnew_916->head; _921 = MEM[(struct node.reorg.reorder *)_920].firstin; MEM[(struct node.reorg.reorder *)_920].firstin = arcnew_916; Here is how dedangled_864 is used: <bb 63> [local count: 2609125]: dedangled_863 = bea_43->head; dedangled_864 = bea_43->tail; goto <bb 65>; [100.00%] <bb 64> [local count: 1813121]: dedangled_865 = bea_43->tail; dedangled_866 = bea_43->head; <bb 65> [local count: 4422246]: # dedangled_867 = PHI <dedangled_863(63), dedangled_865(64)> # dedangled_868 = PHI <dedangled_864(63), dedangled_866(64)> delta_461 = 1; goto <bb 82>; [100.00%] Note, dedangled_868 is used in an ever widening net of phis and operations. Also, the other similar statements dedangled_863 = bea_43->head; dedangled_865 = bea_43->tail; dedangled_866 = bea_43->head; don't seem to be malformed. I tried using a watchpoint to see what was happening but that turned out to be not productive in that it was tripping on something unrelated even if I set it at the start of the pre pass. I'm assuming that some of my code is malformed in some subtle way and I was wondering it anybody had any ideas? I say subtle because this was all working on a slightly different version of gcc without the code of some other Ampere optimizations in the mix (I disabled those optimizations and things still failed.) Note, if you guys don't have any ideas the next approach is adding tons of brute force instrumentation and special purpose sanity checking to the value numbering routine... please help me avoid that. Thanks, Gary CONFIDENTIALITY NOTICE: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and contains information that is confidential and proprietary to Ampere Computing or its subsidiaries. It is to be used solely for the purpose of furthering the parties' business relationship. Any unauthorized review, copying, or distribution of this email (or any attachments thereto) is strictly prohibited. If you are not the intended recipient, please contact the sender immediately and permanently delete the original and any copies of this email and any attachments thereto.
