https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84650
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2018-03-01 CC| |amker.cheng at gmail dot com, | |rguenth at gcc dot gnu.org Target Milestone|--- |8.0 Ever confirmed|0 |1 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- Confirmed. Program received signal SIGSEGV, Segmentation fault. 0x00000000011c1ebe in create_new_iv (data=0x7fffffffd870, cand=0x2cd98f0) at /space/rguenther/src/svn/early-lto-debug/gcc/tree-ssa-loop-ivopts.c:6793 6793 group = data->vgroups[use->group_id]; Missing separate debuginfos, use: zypper install libgmp10-debuginfo-5.1.3-5.46.x86_64 libisl15-debuginfo-0.18-31.1.x86_64 libmpc3-debuginfo-1.0.2-4.55.x86_64 libmpfr4-debuginfo-3.1.2-11.53.x86_64 (gdb) p use $1 = (iv_use *) 0x0 The reason is _possibly_ IL that isn't fully constant propagated, but that can of course happen and we shouldn't rely on that. Bin, can you have a quick look? <bb 2> [local count: 14598063]: _4 = 1; _5 = (unsigned int) _4; _15 = 1 - _5; <bb 3> [local count: 118111601]: # eu_19 = PHI <0(2), eu_13(7)> eu_13 = _15 + eu_19; if (eu_13 <= 1) goto <bb 7>; [87.64%] else goto <bb 6>; [12.36%] <bb 7> [local count: 103513538]: goto <bb 3>; [100.00%]