Following test-case: $ cat error.i a () { a (); } $ UBSAN_OPTIONS="print_stacktrace=1" /dev/shm/objdir/gcc/xgcc -B /dev/shm/objdir/gcc/ -O1 -funroll-loops -c error.i -fmax-errors=1 error.i:1:1: warning: return type defaults to ‘int’ [-Wimplicit-int] a () { a (); } ^ /home/marxin/Programming/gcc2/gcc/regrename.c:1706:64: runtime error: index -1 out of bounds for type 'machine_mode [30]' #0 0x169bea1 in build_def_use /home/marxin/Programming/gcc2/gcc/regrename.c:1706 #1 0x1694d2f in regrename_analyze(bitmap_head*) /home/marxin/Programming/gcc2/gcc/regrename.c:742 #2 0x169dace in regrename_optimize /home/marxin/Programming/gcc2/gcc/regrename.c:1934 #3 0x169dbc6 in execute /home/marxin/Programming/gcc2/gcc/regrename.c:1971 #4 0x1598c61 in execute_one_pass(opt_pass*) /home/marxin/Programming/gcc2/gcc/passes.c:2497 #5 0x159942b in execute_pass_list_1 /home/marxin/Programming/gcc2/gcc/passes.c:2586 #6 0x15994a2 in execute_pass_list_1 /home/marxin/Programming/gcc2/gcc/passes.c:2587 #7 0x15994a2 in execute_pass_list_1 /home/marxin/Programming/gcc2/gcc/passes.c:2587 #8 0x1599522 in execute_pass_list(function*, opt_pass*) /home/marxin/Programming/gcc2/gcc/passes.c:2597 #9 0xc40833 in cgraph_node::expand() /home/marxin/Programming/gcc2/gcc/cgraphunit.c:2139 #10 0xc41740 in expand_all_functions /home/marxin/Programming/gcc2/gcc/cgraphunit.c:2275 #11 0xc430b8 in symbol_table::compile() /home/marxin/Programming/gcc2/gcc/cgraphunit.c:2624 #12 0xc43639 in symbol_table::finalize_compilation_unit() /home/marxin/Programming/gcc2/gcc/cgraphunit.c:2717 #13 0x18a7f43 in compile_file /home/marxin/Programming/gcc2/gcc/toplev.c:480 #14 0x18abd24 in do_compile /home/marxin/Programming/gcc2/gcc/toplev.c:2132 #15 0x18ac208 in toplev::main(int, char**) /home/marxin/Programming/gcc2/gcc/toplev.c:2267 #16 0x31e0f41 in main /home/marxin/Programming/gcc2/gcc/main.c:39 #17 0x7ffff5cfbf49 in __libc_start_main (/lib64/libc.so.6+0x20f49) #18 0x81e9d9 in _start (/dev/shm/objdir/gcc/cc1+0x81e9d9)
So let me take a look.
Author: marxin Date: Sun Mar 18 20:17:10 2018 New Revision: 258634 URL: https://gcc.gnu.org/viewcvs?rev=258634&root=gcc&view=rev Log: Fix UBSAN in regrename.c (PR rtl-optimization/84635). 2018-03-18 Martin Liska <mliska@suse.cz> PR rtl-optimization/84635 * regrename.c (build_def_use): Use matches_mode only when matches >= 0. Modified: trunk/gcc/ChangeLog trunk/gcc/regrename.c
Fixed.