https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84149
Bug ID: 84149 Summary: [8 Regression] SPEC CPU2017 505.mcf/605.mcf ~10% performance regression with r256888 Product: gcc Version: 8.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: ipa Assignee: unassigned at gcc dot gnu.org Reporter: alexander.nesterovskiy at intel dot com CC: marxin at gcc dot gnu.org Target Milestone: --- Minimal options to reproduce regression (x86, 64-bit): -O3 -flto The reason behind the regression is that since r256888 a cost_compare function is not inlined into spec_qsort. These two functions are in different source files. I've managed to force cost_compare to be inlined by creating in the same source file a copy of spec_qsort function with explicit calls of cost_compare. This reverted performance to r256887 level.