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?
