[PATCH] Fix host_size_t_cst_p predicate

Richard Biener richard.guenther@gmail.com
Fri Oct 28 08:37:00 GMT 2016


On Thu, Oct 27, 2016 at 5:06 PM, Martin Liška <mliska@suse.cz> wrote:
> On 10/27/2016 03:35 PM, Richard Biener wrote:
>> On Thu, Oct 27, 2016 at 9:41 AM, Martin Liška <mliska@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.

Richard.

> Thanks,
> Martin
>
>>
>> Richard.
>>
>>> Martin
>



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