From: Richard Biener <richard.guenther@gmail.com>
To: "Martin Liška" <mliska@suse.cz>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] Fold __builtin_memchr (version 3)
Date: Wed, 12 Oct 2016 08:34:00 -0000 [thread overview]
Message-ID: <CAFiYyc1f6Fk+0iyLDj1vZ+ptSS6C9ib0rSte+d0MnJYRupgoEA@mail.gmail.com> (raw)
In-Reply-To: <a14615f2-3363-2cf4-46a8-6fa3d9bec99f@suse.cz>
On Tue, Oct 11, 2016 at 11:38 AM, Martin Liška <mliska@suse.cz> wrote:
> On 10/07/2016 01:01 PM, Richard Biener wrote:
>> On Fri, Oct 7, 2016 at 10:41 AM, Martin Liška <mliska@suse.cz> wrote:
>>> Resending the patch, where I implemented folding in gimple-fold.c
>>>
>>> Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
>>
>> +/* Fold a call to the str{n}{case}cmp builtin pointed by GSI iterator.
>> + FCODE is the name of the builtin. */
>>
>> wrong comment
>
> Fixed.
>
>>
>> +static bool
>> +gimple_fold_builtin_memchr (gimple_stmt_iterator *gsi)
>>
>> + {
>> + replace_call_with_value (gsi, build_int_cst (type, 0));
>>
>> use ptr_type_node (void *) instead of type here and below.
>
> Done.
>
>>
>> + HOST_WIDE_INT offset = r - p1;
>> + if (compare_tree_int (len, offset) <= 0)
>> + {
>>
>> == 0 can occur in which case we have to return a pointer to the
>> first char. I think len < offset can't happen with memchr?
>
> Here I reworked the patch as it's not desired to trigger an undefined behavior
> in a host compiler for cases like: memchr ("", 'x', 5). Thus I switched to strchr
> and aforementioned hunk would make sense.
>
>>
>> + replace_call_with_value (gsi, build_int_cst (type, 0));
>> + return true;
>> + }
>> + else
>> + {
>> + tree temp = fold_build_pointer_plus_hwi_loc (loc, arg1, offset);
>> + replace_call_with_value (gsi, temp);
>>
>> That yields valid GIMPLE by chance, I'd prefer if you'd built that to a
>> stmt and use the replace-with-vops.
>
> Done.
>
> Apart from that I added handling of lhs and the patch supports folding
> of CFN_BUILT_IN_MEMCHR.
>
> One question that comes to my mind is whether there's a possibility
> to fully test gimple folding of all cases if some of them are already
> eaten by generic folding?
>
> Tests of the series have been running.
Ok.
Thanks,
Richard.
> Martin
>
>>
>> + return true;
>> + }
>>
>>
>>> Ready to be installed?
>>> Martin
>
next prev parent reply other threads:[~2016-10-12 8:34 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-17 6:55 [PATCH 0/3] Better folding of 2 string builtin-ins marxin
2016-08-17 6:55 ` [PATCH 1/3] Fold BUILT_IN_STRNCASECMP marxin
2016-08-17 7:10 ` Jakub Jelinek
2016-08-17 7:52 ` Martin Liška
2016-10-07 8:39 ` [PATCH 1/3] Fold __builtin_str{n}{case}cmp functions (version 2) Martin Liška
2016-10-07 10:50 ` Richard Biener
2016-10-11 9:26 ` Martin Liška
2016-10-11 10:27 ` Richard Biener
2016-10-11 9:28 ` [PATCH] Check \0-termination of string in c_getstr Martin Liška
2016-10-11 10:28 ` Richard Biener
2016-10-12 13:14 ` Martin Liška
2016-10-13 15:24 ` [PATCH] Check \0-termination of string in c_getstr (simplified version) Martin Liška
2016-10-14 9:38 ` Richard Biener
2016-10-14 11:10 ` Martin Liška
2016-10-11 9:28 ` [PATCH] Add a helper function: create_tmp Martin Liška
2016-10-11 10:30 ` Richard Biener
2016-10-11 10:31 ` Richard Biener
2016-10-12 10:50 ` Martin Liška
2016-10-11 9:34 ` [PATCH] Fold __builtin_str{n}{case}cmp functions (version 3) Martin Liška
2016-10-12 8:30 ` Richard Biener
2016-10-12 13:17 ` Martin Liška
2016-10-13 15:25 ` [PATCH] Fold __builtin_str{n}{case}cmp functions (simplified version 4) Martin Liška
2016-10-14 11:55 ` Richard Biener
2016-08-17 6:55 ` [PATCH 3/3] Test folding of strn{case}cmp and memchr marxin
2016-08-17 7:52 ` Martin Liška
2016-10-07 8:42 ` [PATCH 3/3] Test folding of str{n}{case}cmp and memchr (version 2) Martin Liška
2016-10-11 9:39 ` [PATCH] Test folding of str{n}{case}cmp and memchr (version 3) Martin Liška
2016-10-12 8:35 ` Richard Biener
2016-10-12 13:20 ` Martin Liška
2016-10-13 15:27 ` [PATCH] Test folding of str{n}{case}cmp and memchr (simplified version 4) Martin Liška
2016-10-14 11:58 ` Richard Biener
2016-08-17 6:55 ` [PATCH 2/3] Smarter folding of __builtin_memchr marxin
2016-08-17 8:41 ` Richard Biener
2016-10-07 8:41 ` [PATCH 2/3] Fold __builtin_memchr (version 2) Martin Liška
2016-10-07 11:01 ` Richard Biener
2016-10-11 9:38 ` [PATCH] Fold __builtin_memchr (version 3) Martin Liška
2016-10-12 8:34 ` Richard Biener [this message]
2016-10-12 8:36 ` Richard Biener
2016-10-12 13:19 ` Martin Liška
2016-10-13 15:26 ` [PATCH] Fold __builtin_memchr (simplified version 4) Martin Liška
2016-10-14 11:57 ` Richard Biener
2016-10-12 13:48 ` [RFC] Possible folding opportunities for string built-ins Martin Liška
2016-10-12 15:55 ` Joseph Myers
2016-10-12 19:45 ` Jim Wilson
2016-10-13 8:38 ` Richard Biener
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