https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88134
--- Comment #21 from Arseny Solokha <asolokha at gmx dot com> --- (In reply to Arseny Solokha from comment #13) > In decl_address_invariant_p() we hit this break: > > 3423 case VAR_DECL: > 3424 if ((TREE_STATIC (op) || DECL_EXTERNAL (op)) > 3425 || DECL_THREAD_LOCAL_P (op) > 3426 || DECL_CONTEXT (op) == current_function_decl > 3427 || decl_function_context (op) == current_function_decl) > 3428 return true; > 3429 break; > > and return false, which in the end becomes what is_gimple_min_invariant() > returns. Indeed, w/ -ftrapping-math we have this at the point of the (failing) assertion: (gdb) p debug_tree (currop->op0) <addr_expr 0x7ffff78a0f60 type <pointer_type 0x7ffff77cf888 type <real_type 0x7ffff77cf498 double DF size <integer_cst 0x7ffff77c8000 constant 64> unit-size <integer_cst 0x7ffff77c8018 constant 8> align:64 warn_if_not_align:0 symtab:0 alias-set 1 canonical-type 0x7ffff77cf498 precision:64 pointer_to_this <pointer_type 0x7ffff77cf888>> public unsigned SI size <integer_cst 0x7ffff77b6f90 constant 32> unit-size <integer_cst 0x7ffff77b6fa8 constant 4> align:32 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type 0x7ffff77cf888> arg:0 <var_decl 0x7ffff7fcf5a0 D.1473 type <real_type 0x7ffff77cf498 double> addressable used ignored read DF gcpt737x.c:9:5 size <integer_cst 0x7ffff77c8000 64> unit-size <integer_cst 0x7ffff77c8018 8> align:64 warn_if_not_align:0 context <function_decl 0x7ffff78a5c00 i6>>> $1 = void while w/ -fno-trapping-math: (gdb) p debug_tree (currop->op0) <addr_expr 0x7ffff78cf0c0 type <pointer_type 0x7ffff77cf888 type <real_type 0x7ffff77cf498 double DF size <integer_cst 0x7ffff77c8000 constant 64> unit-size <integer_cst 0x7ffff77c8018 constant 8> align:64 warn_if_not_align:0 symtab:0 alias-set 1 canonical-type 0x7ffff77cf498 precision:64 pointer_to_this <pointer_type 0x7ffff77cf888>> public unsigned SI size <integer_cst 0x7ffff77b6f90 constant 32> unit-size <integer_cst 0x7ffff77b6fa8 constant 4> align:32 warn_if_not_align:0 symtab:0 alias-set 2 canonical-type 0x7ffff77cf888> arg:0 <var_decl 0x7ffff7fcf6c0 D.1480 type <real_type 0x7ffff77cf498 double> addressable used ignored DF gcpt737x.c:9:5 size <integer_cst 0x7ffff77c8000 64> unit-size <integer_cst 0x7ffff77c8018 8> align:64 warn_if_not_align:0>> $1 = void There's no function context in the latter case, so 3427 || decl_function_context (op) == current_function_decl) evaluates to false, and gcc_assert() eventually fails. In case of -fno-trapping-math this context gets assigned during the second call to gimple_add_tmp_var(): 751 DECL_CONTEXT (tmp) = current_function_decl; 752 DECL_SEEN_IN_BIND_EXPR_P (tmp) = 1; and I fail to see why this doesn't happen w/ -ftrapping-math. The assignment clearly happens on the second invocation of gimple_add_tmp_var() but watchpoint doesn't fire. -fno-trapping-math: Breakpoint 1, gimple_add_tmp_var (tmp=0x7ffff7fcf510) at gcc/tree.h:3270 (gdb) Continuing. Hardware watchpoint 3: -location DECL_CONTEXT (tmp) Old value = (tree_node *) 0x0 New value = (tree_node *) 0x7ffff78a5c00 gimple_add_tmp_var (tmp=0x7ffff7fcf510) at gcc/gimplify.c:752 (gdb) Continuing. Breakpoint 1, gimple_add_tmp_var (tmp=0x7ffff7fcf5a0) at gcc/tree.h:3270 (gdb) Continuing. Hardware watchpoint 4: -location TREE_OPERAND (currop->op0, 0).decl_minimal.context Old value = (tree_node *) 0x0 New value = (tree_node *) 0x7ffff78a5c00 gimple_add_tmp_var (tmp=0x7ffff7fcf5a0) at gcc/gimplify.c:752 (gdb) Continuing. Breakpoint 1, gimple_add_tmp_var (tmp=0x7ffff7fcf630) at gcc/tree.h:3270 (gdb) Continuing. Breakpoint 2, create_component_ref_by_pieces_1 (block=0x7ffff78a3888, ref=0x1e4d090, operand=0x7fffffffc7d0, stmts=0x7fffffffc868) at gcc/tree-ssa-pre.c:2520 (gdb) Continuing. [Inferior 1 (process 4261) exited normally] -ftrapping-math: Breakpoint 1, gimple_add_tmp_var (tmp=0x7ffff7fcf510) at gcc/tree.h:3270 (gdb) Continuing. Hardware watchpoint 3: -location DECL_CONTEXT (tmp) Old value = (tree_node *) 0x0 New value = (tree_node *) 0x7ffff78a5c00 gimple_add_tmp_var (tmp=0x7ffff7fcf510) at gcc/gimplify.c:752 (gdb) Continuing. Breakpoint 1, gimple_add_tmp_var (tmp=0x7ffff7fcf5a0) at gcc/tree.h:3270 (gdb) Continuing. Breakpoint 1, gimple_add_tmp_var (tmp=0x7ffff7fcf630) at gcc/tree.h:3270 (gdb) Continuing. Breakpoint 2, create_component_ref_by_pieces_1 (block=0x7ffff78a3138, ref=0x1e4cb40, operand=0x7fffffffc960, stmts=0x7fffffffc9f8) at gcc/tree-ssa-pre.c:2520 (gdb) Continuing. during GIMPLE pass: pre cptctz2r.c: In function 'i6': cptctz2r.c:4:1: internal compiler error: in create_component_ref_by_pieces_1, at tree-ssa-pre.c:2520 What should I look at next?