https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90055
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Priority|P3 |P2 Status|UNCONFIRMED |NEW Known to work| |6.5.0, 8.1.0 Keywords| |needs-bisection, wrong-code Last reconfirmed| |2019-04-12 CC| |marxin at gcc dot gnu.org Ever confirmed|0 |1 Summary|Incorrect result with |[7 Regression] Incorrect |ffast-math + tree-vectorize |result with ffast-math + | |tree-vectorize Target Milestone|--- |7.5 Known to fail| |7.1.0 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- Confirmed - this is likely a duplicate since it seems to be fixed on the GCC 8 branch and trunk. -mavx2 -mfma triggers the issue. w/o -mfma the GCC 7 branch produces -0.0. The GCC 8 branch doesn't vectorize the loop at t.c:104 but the basic-block at 103. Note I observe different unrolling between 7 and 8 so the actual issue might be latent. Martin, can you bisect what fixed this?