http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58247
Bug ID: 58247 Summary: ICE in tree_unroll_loops_completely at -O3 (both 32-bit and 64-bit modes) Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: su at cs dot ucdavis.edu The following code causes an ICE when compiled with the current gcc trunk at -O3 on x86_64-linux in both 32-bit and 64-bit modes. This is a regression from 4.8.x. It is likely a duplicate of 57592, although the stack traces are somewhat different. $ gcc-trunk -v gcc version 4.9.0 20130826 (experimental) [trunk revision 201986] (GCC) $ gcc-trunk -O2 -c reduced.c $ gcc-4.8 -O3 -c reduced.c $ gcc-trunk -O3 -c reduced.c reduced.c: In function ‘foo’: reduced.c:14:6: internal compiler error: Segmentation fault void foo () ^ 0x7e6a0f crash_signal ../../gcc-trunk/gcc/toplev.c:335 0x80f55b ssa_default_def(function*, tree_node*) ../../gcc-trunk/gcc/tree-dfa.c:314 0x80f820 get_or_create_ssa_default_def(function*, tree_node*) ../../gcc-trunk/gcc/tree-dfa.c:362 0x82924a get_reaching_def ../../gcc-trunk/gcc/tree-into-ssa.c:1184 0x82f1fa maybe_replace_use ../../gcc-trunk/gcc/tree-into-ssa.c:1784 0x82f1fa rewrite_update_stmt ../../gcc-trunk/gcc/tree-into-ssa.c:1967 0x82f1fa rewrite_update_enter_block ../../gcc-trunk/gcc/tree-into-ssa.c:2136 0xb4d77a walk_dominator_tree(dom_walk_data*, basic_block_def*) ../../gcc-trunk/gcc/domwalk.c:210 0x827f13 rewrite_blocks ../../gcc-trunk/gcc/tree-into-ssa.c:2216 0x82e4ae update_ssa(unsigned int) ../../gcc-trunk/gcc/tree-into-ssa.c:3319 0x8963fc rewrite_into_loop_closed_ssa(bitmap_head_def*, unsigned int) ../../gcc-trunk/gcc/tree-ssa-loop-manip.c:501 0xbb23fa tree_unroll_loops_completely(bool, bool) ../../gcc-trunk/gcc/tree-ssa-loop-ivcanon.c:1205 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <http://gcc.gnu.org/bugs.html> for instructions. $ ---------------------------------------------- int a, b, c; unsigned int d; void baz(); void bar () { int e; for (d = 1; d < 2; d = d - 1) for (e = 24; e; e = e - 3) a &= b >= e; } void foo () { for (;; b++) for (c = 0; c < 1; c++) { bar (); baz (); } }