[PATCH] Aarch64 Neon ACLE scalar instrinsic name mangling with BHSD suffix

Kevin Qin kevinqindev at gmail.com
Mon Aug 19 02:43:00 PDT 2013


Hi Joey,

   Thanks a lot for your suggestions. I improved my patch as your good
advice. I wish to implement some of ACLE intrinsic based on my patch as
test, but the full implementation of one ACLE intrinsic need to commit on
both llvm and clang. More important thing is,  all scalar ACLE intrinsic
are classified to different tables, and these tables are implemented in
parallel but none of them is accomplished.  There are complex dependence
among intrinsic and may be rewrite frequently.  The main purpose posting
this patch at moment is to decrease overlap on such base module and make
our parallel development more efficient.

Best Regards,
Kevin Qin


2013/8/16 Joey Gouly <joey.gouly at arm.com>

> Hi Kevin,
>
> Clang patches should be sent to cfe-commits. I cc’d them in for you.
>
> You could test this patch by including an ACLE function that you have
> implemented, that way we can see it works. Or if you are going to submit
> those soon, maybe it can go in without a test for now. Let’s see what
> others
> think about that.
>
> Just two minor points.
>
> > +static std::string Insert_BHSD_Suffix(StringRef typestr){
>
> This should just return a 'char'.
>
> > +/// Insert proper 'b' 'h' 's' 'd' behind function name if prefix 'S' is
> used.
> Can you change that to something like
>   Insert proper 'b', 'h', 's', 'd' suffix if 'S' prefix is used.
>
> Thanks
>
> From: llvm-commits-bounces at cs.uiuc.edu
> [mailto:llvm-commits-bounces at cs.uiuc.edu] On Behalf Of Kevin Qin
> Sent: 16 August 2013 10:46
> To: llvm-commits at cs.uiuc.edu
> Subject: [PATCH] Aarch64 Neon ACLE scalar instrinsic name mangling with
> BHSD
> suffix
>
> This patch is used to add ‘bhsd’ suffix in Neon ACLE scalar function name.
> 1. A new type prefix ‘S’ is defined in
> tools/clang/include/clang/Basic/arm_neon.td, which is used to mark whether
> enable ‘bhsd’ suffix mangle.
> 2. If prefix ‘S’ is found before data type, proper suffix will be added
> according below rule:
> Data Type  Suffix
>   i8 -> b
>   i16 -> h
>   i32 f32 -> s
>   i64 f64 -> d
>
> For example,
> If we define a new ACLE function in arm_neon.td like:
>
> def FABD : SInst<”vabd”, “sss”,  “ScSsSiSlSfSd”>
>
> Then, rebuild llvm. We would see below in
> INSTALL_PATH/lib/clang/3.4/include/arm_neon.h
>
> __ai int8_t vabdb_s8(int8_t __a, int8_t __b) {
>   return (int8_t)__builtin_neon_vabdb_s8(__a, __b); }
> __ai int16_t vabdh_s16(int16_t __a, int16_t __b) {
>   return (int16_t)__builtin_neon_vabdh_s8(__a, __b); }
>>
> Proper suffix is inserted in both ACLE intrinsics and builtin functions.
>
> Because this patch only works on llvm building time, so I have no idea on
> writing test case for this patch. Fortunately, this patch won’t effect on
> any already defined ACLE functions, for its function depending on the new
> defined prefix ‘S’. So It is safe for current system and is developed to
> help implement new scalar ACLE intrinsics in parallel.
>
> You can see each scalar ACLE function corresponds to an unique builtin
> function. At beginning, I planned to let series of ACLE functions with the
> same semantics reuse one builtin function. But this would introduce extra
> unnecessary convert expression in IR, for different data types have
> different data width. If I promote all data types to i64 and use single
> builtin function, then there will be only an i64 version builtin function
> existing in IR. Though I can add extra arg in builtin function to record
> the
> original data type, but extra data convert IR(sign extension before call
> and
> truncation after call) still exists. This will increase the difficulty in
> coding lower patterns in backend.
>
>
>
>
>


-- 
Best Regards,

Kevin Qin
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