Hello, I am encountering an internal compiler error when compiling with -O2 internal compiler error: in get_constraint_for_ptr_offset, at tree-ssa-structalias.c:3155 I see this error when using the MinGW-w64 version of gcc, both version 7.2.0 on Fedora 27 and version 6.4.0 on Fedora 25. I do not see the error with MinGW version 4.9.2 on Fedora 21. I do not see this error when compiling natively for Linux on Centos 6 (4.4.7), Centos 7 (4.8.5), Fedora 21 (4.9.2), Fedora 25 (6.4.1), or Fedora 27 (7.2.1). A backtrace: #0 0x00007ffff649db90 in exit () from /lib64/libc.so.6 #1 0x0000000000f615a7 in diagnostic_action_after_output(diagnostic_context*, diagnostic_t) () #2 0x0000000000f61cdd in diagnostic_report_diagnostic(diagnostic_context*, diagnostic_info*) () #3 0x0000000000f6219f in diagnostic_impl(rich_location*, int, char const*, __va_list_tag (*) [1], diagnostic_t) () #4 0x0000000000f62dc5 in internal_error(char const*, ...) () #5 0x0000000000f614f4 in fancy_abort(char const*, int, char const*) () #6 0x00000000009f0703 in get_constraint_for_ptr_offset(tree_node*, tree_node*, vec<constraint_expr, va_heap, vl_ptr>*) () #7 0x00000000009f2162 in find_func_aliases(function*, gimple*) () #8 0x00000000009f79ef in compute_may_aliases() () #9 0x00000000007c6782 in execute_function_todo(function*, void*) () #10 0x00000000007c7853 in execute_todo(unsigned int) () #11 0x00000000007c95ee in execute_one_pass(opt_pass*) () #12 0x00000000007c9c71 in execute_pass_list_1(opt_pass*) () #13 0x00000000007c9c83 in execute_pass_list_1(opt_pass*) () #14 0x00000000007c9cc5 in execute_pass_list(function*, opt_pass*) () #15 0x000000000054f2c5 in cgraph_node::expand() () #16 0x00000000005505e1 in symbol_table::compile() [clone .part.51] () #17 0x0000000000552257 in symbol_table::finalize_compilation_unit() () #18 0x0000000000880d2a in compile_file() () #19 0x00000000004294d5 in toplev::main(int, char**) () #20 0x000000000042b83b in main () The problem does not occur with -O. I attempted to narrow down the error to a particular optimization flag by adding the additional optimization flags enabled by -O2, as documented in the man page. However, this approach produced slightly different behavior: internal compiler error: Segmentation fault I found two flags, either of which added to -O triggers a segfault: -ftree-pre and -fcode-hoisting. A backtrace from running with "-O -ftree-pre" #0 0x00000000009b2c1f in find_or_generate_expression(basic_block_def*, tree_node*, gimple**) () #1 0x00000000009b234e in create_expression_by_pieces(basic_block_def*, pre_expr_d*, gimple**, tree_node*) () #2 0x00000000009b43d2 in insert_into_preds_of_block(basic_block_def*, unsigned int, vec<pre_expr_d*, va_heap, vl_ptr>) () #3 0x00000000009b666b in insert_aux(basic_block_def*, bool, bool) () #4 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #5 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #6 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #7 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #8 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #9 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #10 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #11 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #12 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #13 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #14 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #15 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #16 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #17 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #18 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #19 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #20 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #21 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #22 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #23 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #24 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #25 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #26 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #27 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #28 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #29 0x00000000009b7c19 in (anonymous namespace)::pass_pre::execute(function*) () #30 0x00000000007c94a9 in execute_one_pass(opt_pass*) () #31 0x00000000007c9c71 in execute_pass_list_1(opt_pass*) () #32 0x00000000007c9c83 in execute_pass_list_1(opt_pass*) () #33 0x00000000007c9cc5 in execute_pass_list(function*, opt_pass*) () #34 0x000000000054f2c5 in cgraph_node::expand() () #35 0x00000000005505e1 in symbol_table::compile() [clone .part.51] () #36 0x0000000000552257 in symbol_table::finalize_compilation_unit() () #37 0x0000000000880d2a in compile_file() () #38 0x00000000004294d5 in toplev::main(int, char**) () #39 0x000000000042b83b in main () And a backtrace with "-O -fcode-hoisting" #0 0x00000000009b2c1f in find_or_generate_expression(basic_block_def*, tree_node*, gimple**) () #1 0x00000000009b234e in create_expression_by_pieces(basic_block_def*, pre_expr_d*, gimple**, tree_node*) () #2 0x00000000009b64f8 in insert_aux(basic_block_def*, bool, bool) () #3 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #4 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #5 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #6 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #7 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #8 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #9 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #10 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #11 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #12 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #13 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #14 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #15 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #16 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #17 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #18 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #19 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #20 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #21 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #22 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #23 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #24 0x00000000009b59a8 in insert_aux(basic_block_def*, bool, bool) () #25 0x00000000009b7c19 in (anonymous namespace)::pass_pre::execute(function*) () #26 0x00000000007c94a9 in execute_one_pass(opt_pass*) () #27 0x00000000007c9c71 in execute_pass_list_1(opt_pass*) () #28 0x00000000007c9c83 in execute_pass_list_1(opt_pass*) () #29 0x00000000007c9cc5 in execute_pass_list(function*, opt_pass*) () #30 0x000000000054f2c5 in cgraph_node::expand() () #31 0x00000000005505e1 in symbol_table::compile() [clone .part.51] () #32 0x0000000000552257 in symbol_table::finalize_compilation_unit() () #33 0x0000000000880d2a in compile_file() () #34 0x00000000004294d5 in toplev::main(int, char**) () #35 0x000000000042b83b in main () Passing "-O2 -fno-tree-pre -fno-code-hoisting" to gcc still triggers the segfault. At this point, I do not have a small piece of code that I can share that triggers the problem, though I will try to do so. Can someone offer some suggestions on how to avoid the problem without turning off all of -O2? Or how I can provide more information to track down the underlying problem? Thank you, Matt
