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Re: extract_range_from_binary* cleanups for VRP
- From: Martin Liška <mliska at suse dot cz>
- To: Aldy Hernandez <aldyh at redhat dot com>, gcc-patches <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 3 Jul 2018 14:16:42 +0200
- Subject: Re: extract_range_from_binary* cleanups for VRP
- References: <47b890d4-33e2-bd24-8054-5f220b7bfc26@redhat.com>
Hi.
It caused UBSAN errors:
$ cat ubsan.i
int a;
void d() { int c, b = 8 - a; }
$ /home/marxin/Programming/gcc2/objdir/./gcc/xgcc -B/home/marxin/Programming/gcc2/objdir/./gcc/ ubsan.i -c -O2
../../gcc/tree-vrp.c:1715:26: runtime error: load of value 255, which is not a valid value for type 'bool'
#0 0x3246ca2 in extract_range_from_binary_expr_1(value_range*, tree_code, tree_node*, value_range*, value_range*) ../../gcc/tree-vrp.c:1715
#1 0x34aa8b6 in vr_values::extract_range_from_binary_expr(value_range*, tree_code, tree_node*, tree_node*, tree_node*) ../../gcc/vr-values.c:794
#2 0x34b45fa in vr_values::extract_range_from_assignment(value_range*, gassign*) ../../gcc/vr-values.c:1455
#3 0x494cfd5 in evrp_range_analyzer::record_ranges_from_stmt(gimple*, bool) ../../gcc/gimple-ssa-evrp-analyze.c:293
#4 0x4942548 in evrp_dom_walker::before_dom_children(basic_block_def*) ../../gcc/gimple-ssa-evrp.c:139
#5 0x487652b in dom_walker::walk(basic_block_def*) ../../gcc/domwalk.c:353
#6 0x49470f9 in execute_early_vrp ../../gcc/gimple-ssa-evrp.c:310
#7 0x49470f9 in execute ../../gcc/gimple-ssa-evrp.c:347
#8 0x1fc4a0e in execute_one_pass(opt_pass*) ../../gcc/passes.c:2446
#9 0x1fc8b47 in execute_pass_list_1 ../../gcc/passes.c:2535
#10 0x1fc8b8e in execute_pass_list_1 ../../gcc/passes.c:2536
#11 0x1fc8c68 in execute_pass_list(function*, opt_pass*) ../../gcc/passes.c:2546
#12 0x2004c85 in do_per_function_toporder(void (*)(function*, void*), void*) ../../gcc/passes.c:1688
#13 0x2005e9a in execute_ipa_pass_list(opt_pass*) ../../gcc/passes.c:2894
#14 0xfcfa79 in ipa_passes ../../gcc/cgraphunit.c:2400
#15 0xfcfa79 in symbol_table::compile() ../../gcc/cgraphunit.c:2536
#16 0xfdc52a in symbol_table::finalize_compilation_unit() ../../gcc/cgraphunit.c:2696
#17 0x25115e4 in compile_file ../../gcc/toplev.c:479
#18 0x9278af in do_compile ../../gcc/toplev.c:2086
#19 0x9278af in toplev::main(int, char**) ../../gcc/toplev.c:2221
#20 0x92a79a in main ../../gcc/main.c:39
#21 0x7ffff659c11a in __libc_start_main ../csu/libc-start.c:308
#22 0x92a8c9 in _start (/home/marxin/Programming/gcc2/objdir/gcc/cc1+0x92a8c9)
It's because neg_min_op0, or any other from:
bool neg_min_op0, neg_min_op1, neg_max_op0, neg_max_op1;
Martin