From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Richard Biener <richard.guenther@gmail.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>,
Richard Sandiford <richard.sandiford@arm.com>,
Segher Boessenkool <segher@kernel.crashing.org>,
"Joseph S. Myers" <joseph@codesourcery.com>,
Andreas Krebbel <krebbel@linux.ibm.com>,
Robin Dapp <rdapp@linux.ibm.com>
Subject: Re: [PATCH v3 1/9] Allow COND_EXPR and VEC_COND_EXPR condtions to trap
Date: Fri, 06 Sep 2019 15:45:00 -0000 [thread overview]
Message-ID: <6DCAE849-42F6-4538-8AE1-EE091F01FC3B@linux.ibm.com> (raw)
In-Reply-To: <CAFiYyc2k_andqHebmS8KATMZ3AWP=ch+3WzZK6do5DGvM3ifxg@mail.gmail.com>
> Am 06.09.2019 um 13:07 schrieb Richard Biener <richard.guenther@gmail.com>:
>
> On Thu, Sep 5, 2019 at 1:10 PM Ilya Leoshkevich <iii@linux.ibm.com> wrote:
>>
>> Right now gimplifier does not allow VEC_COND_EXPR's condition to trap
>> and introduces a temporary if this could happen, for example, generating
>>
>> _5 = _4 > { 2.0e+0, 2.0e+0, 2.0e+0, 2.0e+0 };
>> _6 = VEC_COND_EXPR <_5, { -1, -1, -1, -1 }, { 0, 0, 0, 0 }>;
>>
>> from GENERIC
>>
>> VEC_COND_EXPR < (*b > { 2.0e+0, 2.0e+0, 2.0e+0, 2.0e+0 }) ,
>> { -1, -1, -1, -1 } ,
>> { 0, 0, 0, 0 } >
>>
>> This is not necessary and makes the resulting GIMPLE harder to analyze.
>> In particular, one of the next patches in series needs to get to
>> VEC_COND_EXPR's comparison code, which is not possible when a temporary
>> is introduced.
>>
>> This patch takes special care to avoid introducing trapping comparisons
>> in GIMPLE_COND. They are not allowed, because they would require 3
>> outgoing edges (then, else and EH), which is awkward to say the least.
>> Therefore, computations of such conditions should live in their own basic
>> blocks.
>
> Comments inline (thanks for the work btw)
>
>> #endif /* GCC_GIMPLE_EXPR_H */
>> diff --git a/gcc/gimple.c b/gcc/gimple.c
>> index 633ef512a19..fd14fbec15e 100644
>> --- a/gcc/gimple.c
>> +++ b/gcc/gimple.c
>> @@ -2144,6 +2144,8 @@ gimple_could_trap_p_1 (gimple *s, bool include_mem, bool include_stores)
>> op = gimple_assign_rhs_code (s);
>> if (get_gimple_rhs_class (op) == GIMPLE_BINARY_RHS)
>> div = gimple_assign_rhs2 (s);
>> + else if (op == COND_EXPR || op == VEC_COND_EXPR)
>> + op = TREE_CODE (gimple_assign_rhs1 (s));
>
> I think this is not correct since we can have
>
> int i = fp > 1. ? intval1 : intval2
>
> and thus FLOAT_TYPE_P (t) is wrong. You need to do
>
> t = TREE_TYPE (op);
>
> as well I think.
Doesn't this mean there is a problem with the existing logic too? If `s`
is
int i = fp > 1.;
then
t = gimple_expr_type (s);
would give us BOOLEAN_TYPE instead of REAL_TYPE.
Also, the new logic will probably be a bit more complicated, since I
will first have to do:
tree cond = gimple_assign_rhs1 (s);
then see if `cond` is not e.g. an SSA_NAME, but rather a tcc_comparison,
and only then
t = TREE_TYPE (TREE_OPERAND (cond, 0))
So I'd rather send a new version before merging this :-)
next prev parent reply other threads:[~2019-09-06 15:45 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-05 11:10 [PATCH v3 0/9] S/390: Use signaling FP comparison instructions Ilya Leoshkevich
2019-09-05 11:10 ` [PATCH v3 1/9] Allow COND_EXPR and VEC_COND_EXPR condtions to trap Ilya Leoshkevich
2019-09-06 11:07 ` Richard Biener
2019-09-06 15:45 ` Ilya Leoshkevich [this message]
2019-09-09 8:43 ` Richard Biener
2019-09-05 11:11 ` [PATCH v3 5/9] S/390: Implement vcond expander for V1TI,V1TF Ilya Leoshkevich
2019-09-30 14:51 ` Andreas Krebbel
2019-09-05 11:11 ` [PATCH v3 6/9] S/390: Remove code duplication in vec_unordered<mode> Ilya Leoshkevich
2019-09-30 14:41 ` Andreas Krebbel
2019-09-05 11:11 ` [PATCH v3 4/9] S/390: Do not use signaling vector comparisons on z13 Ilya Leoshkevich
2019-09-06 10:34 ` Segher Boessenkool
2019-09-30 13:36 ` Ilya Leoshkevich
2019-10-01 0:24 ` Segher Boessenkool
2019-09-05 11:11 ` [PATCH v3 3/9] Introduce can_vector_compare_p function Ilya Leoshkevich
2019-09-06 12:58 ` Richard Sandiford
2019-09-05 11:11 ` [PATCH v3 2/9] Introduce rtx_alloca, alloca_raw_REG and alloca_rtx_fmt_* Ilya Leoshkevich
2019-09-06 11:09 ` Richard Biener
2019-09-06 12:40 ` Richard Sandiford
2019-09-30 15:00 ` Ilya Leoshkevich
2019-09-05 11:12 ` [PATCH v3 8/9] S/390: Use signaling FP comparison instructions Ilya Leoshkevich
2019-09-05 11:12 ` [PATCH v3 7/9] S/390: Remove code duplication in vec_* comparison expanders Ilya Leoshkevich
2019-09-30 14:50 ` Andreas Krebbel
2019-09-05 11:12 ` [PATCH v3 9/9] S/390: Test signaling FP comparison instructions Ilya Leoshkevich
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=6DCAE849-42F6-4538-8AE1-EE091F01FC3B@linux.ibm.com \
--to=iii@linux.ibm.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=joseph@codesourcery.com \
--cc=krebbel@linux.ibm.com \
--cc=rdapp@linux.ibm.com \
--cc=richard.guenther@gmail.com \
--cc=richard.sandiford@arm.com \
--cc=segher@kernel.crashing.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).