https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
Bug ID: 78994 Summary: -Ofast makes aarch64 C++ benchmark slower Product: gcc Version: 5.4.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end Assignee: unassigned at gcc dot gnu.org Reporter: tulipawn at gmail dot com Target Milestone: --- Created attachment 40463 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40463&action=edit Preprocessed source + assembly files After make && ./build/dsp-bench, the results look as follows @ -O3 -mcpu=cortex-a53 -ftree-vectorize iir: 67945 ns per loop iir_2: 67952 ns per loop @ -Ofast -mcpu=cortex-a53 -ftree-vectorize iir: 73367 ns per loop iir_2: 73349 ns per loop