On 10/31/2016 01:12 AM, Richard Sandiford wrote:
> Richard Biener <richard.guent...@gmail.com> writes:
>> On Thu, Oct 27, 2016 at 5:06 PM, Martin Liška <mli...@suse.cz> wrote:
>>> On 10/27/2016 03:35 PM, Richard Biener wrote:
>>>> On Thu, Oct 27, 2016 at 9:41 AM, Martin Liška <mli...@suse.cz> wrote:
>>>>> Running simple test-case w/o the proper header file causes ICE:
>>>>> strncmp ("a", "b", -1);
>>>>>
>>>>> 0xe74462 tree_to_uhwi(tree_node const*)
>>>>> ../../gcc/tree.c:7324
>>>>> 0x90a23f host_size_t_cst_p
>>>>> ../../gcc/fold-const-call.c:63
>>>>> 0x90a23f fold_const_call(combined_fn, tree_node*, tree_node*,
>>>>> tree_node*, tree_node*)
>>>>> ../../gcc/fold-const-call.c:1512
>>>>> 0x787b01 fold_builtin_3
>>>>> ../../gcc/builtins.c:8385
>>>>> 0x787b01 fold_builtin_n(unsigned int, tree_node*, tree_node**, int, bool)
>>>>> ../../gcc/builtins.c:8465
>>>>> 0x9052b1 fold(tree_node*)
>>>>> ../../gcc/fold-const.c:11919
>>>>> 0x6de2bb c_fully_fold_internal
>>>>> ../../gcc/c/c-fold.c:185
>>>>> 0x6e1f6b c_fully_fold(tree_node*, bool, bool*)
>>>>> ../../gcc/c/c-fold.c:90
>>>>> 0x67cbbf c_process_expr_stmt(unsigned int, tree_node*)
>>>>> ../../gcc/c/c-typeck.c:10369
>>>>> 0x67cfbd c_finish_expr_stmt(unsigned int, tree_node*)
>>>>> ../../gcc/c/c-typeck.c:10414
>>>>> 0x6cb578 c_parser_statement_after_labels
>>>>> ../../gcc/c/c-parser.c:5430
>>>>> 0x6cd333 c_parser_compound_statement_nostart
>>>>> ../../gcc/c/c-parser.c:4944
>>>>> 0x6cdbde c_parser_compound_statement
>>>>> ../../gcc/c/c-parser.c:4777
>>>>> 0x6c93ac c_parser_declaration_or_fndef
>>>>> ../../gcc/c/c-parser.c:2176
>>>>> 0x6d51ab c_parser_external_declaration
>>>>> ../../gcc/c/c-parser.c:1574
>>>>> 0x6d5c09 c_parser_translation_unit
>>>>> ../../gcc/c/c-parser.c:1454
>>>>> 0x6d5c09 c_parse_file()
>>>>> ../../gcc/c/c-parser.c:18173
>>>>> 0x72ffd2 c_common_parse_file()
>>>>> ../../gcc/c-family/c-opts.c:1087
>>>>>
>>>>> Following patch improves the host_size_t_cst_p predicate.
>>>>>
>>>>> Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
>>>>>
>>>>> Ready to be installed?
>>>>
>>>> I believe the wi::min_precision (t, UNSIGNED) <= sizeof (size_t) *
>>>> CHAR_BIT test is now redundant.
>>>>
>>>> OTOH it was probably desired to allow -1 here? A little looking back
>>>> in time should tell.
>>>
>>> Ok, it started with r229922, where it was changed from:
>>>
>>> if (tree_fits_uhwi_p (len) && p1 && p2)
>>> {
>>> const int i = strncmp (p1, p2, tree_to_uhwi (len));
>>> ...
>>>
>>> to current version:
>>>
>>> case CFN_BUILT_IN_STRNCMP:
>>> {
>>> bool const_size_p = host_size_t_cst_p (arg2, &s2);
>>>
>>> Thus I'm suggesting to change to back to it.
>>>
>>> Ready to be installed?
>>
>> Let's ask Richard.
>
> The idea with the:
>
> wi::min_precision (t, UNSIGNED) <= sizeof (size_t) * CHAR_BIT
>
> test was to stop us attempting 64-bit size_t operations on ILP32 hosts.
> I think we still want that.
OK, so is the consensus to add tree_fits_uhwi_p predicate to the current
wi::min_precision check, right?
Thanks,
Martin
>
> Thanks,
> Richard
>
