https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84552
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Priority|P4 |P2 Target Milestone|8.0 |6.5 Summary|[8 Regression] Compile time |[6/7/8 Regression] Compile |hog w/ -O2 |time hog w/ -O2 |-floop-nest-optimize |-floop-nest-optimize |-fno-tree-copy-prop |-fno-tree-copy-prop |-fno-tree-fre |-fno-tree-fre |-fno-tree-loop-ivcanon |-fno-tree-loop-ivcanon --- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> --- So this is really a latent issue and not dependent on -floop-nest-optimize. It materializes during unrolling where we perform SCEV analysis on not up-to-date SSA form when analyzing.