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
