https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81245
Bug ID: 81245 Summary: [8 Regression] ICE building calculix with -Ofast Product: gcc Version: 7.0 Status: UNCONFIRMED Keywords: ice-on-valid-code Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: pinskia at gcc dot gnu.org Target Milestone: --- Target: aarch64-linux-gnu This started with my copysign patch. Here is a reduced testcase: double sg[18]; void f(void) { for (int i = 0 ;i < 18;i++) { if (sg[i] < 0.0) sg[i] = -1.0; else sg[i] = 1.0; } } ---- CUT --- Compile with -Ofast. 0x6f53b4 flow_bb_inside_loop_p(loop const*, basic_block_def const*) ../../gcc/gcc/cfgloop.c:794 0xd82b5b vect_stmt_relevant_p ../../gcc/gcc/tree-vect-stmts.c:326 0xd8366f vect_mark_stmts_to_be_vectorized(_loop_vec_info*) ../../gcc/gcc/tree-vect-stmts.c:664 0xdae127 vect_analyze_loop_2 ../../gcc/gcc/tree-vect-loop.c:1944 0xdae127 vect_analyze_loop(loop*, _loop_vec_info*) ../../gcc/gcc/tree-vect-loop.c:2403 0xdc4e4f vectorize_loops() ../../gcc/gcc/tree-vectorizer.c:614 Please submit a full bug report, >From what I can tell, is ifcvt clones the loop and ifconverts that loop only and enables it only for vectorization and that cloned loop has the a>0.0?1.0:-1.0 optimized to copysign.