https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64058
Bug ID: 64058 Summary: Performance degradation after r216304 Product: gcc Version: 5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: izamyatin at gmail dot com Target: x86 Created attachment 34101 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34101&action=edit reproducer Got a performance regression for the codes similar to attached test (well, rather specific, my simple attempts to reduce it more failed). Regression root cause is not obviuos at the first glance but noticed that after r216304 we have l1=u1 placed differently after expand pass. Seems for r216303 this assignment was sinked lower and this potentially affects live ranges and thus performance. GCC options: -Ofast -flto -m32