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From: "Kewen.Lin" <>
To: Segher Boessenkool <>
Cc: GCC Patches <>,
	David Edelsohn <>,
	Peter Bergner <>,
	Michael Meissner <>
Subject: Re: [PATCH 2/2] rs6000: Refine integer comparison handlings in rs6000_emit_vector_compare
Date: Thu, 17 Nov 2022 15:52:26 +0800	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Hi Segher,

Thanks for the comments!

on 2022/11/17 02:58, Segher Boessenkool wrote:
> Hi!
> On Wed, Nov 16, 2022 at 02:51:04PM +0800, Kewen.Lin wrote:
>> The current handlings in rs6000_emit_vector_compare is a bit
>> complicated to me, especially after we emit vector float
>> comparison insn with the given code directly.  This patch is
>> to refine the handlings for vector integer comparison operators,
>> it becomes not recursive, and we don't need the helper function
>> rs6000_emit_vector_compare_inner any more.
> That sounds nice.
>>    /* In, we support all kinds of vector float point
>>       comparison operators in a comparison rtl pattern, we can
>>       just emit the comparison rtx insn directly here.  Besides,
>>       we should have a centralized place to handle the possibility
>> -     of raising invalid exception.  */
>> -  if (GET_MODE_CLASS (dmode) == MODE_VECTOR_FLOAT)
>> +     of raising invalid exception.  Also emit directly for vector
>> +     integer comparison operators EQ/GT/GTU.  */
>> +      || rcode == EQ
>> +      || rcode == GT
>> +      || rcode == GTU)
> The comment still says it handles FP only.  That would be best to keep
> imo: add a separate block of code to handle the integer stuff you want
> to add.  You get the same or better generated code, the compiler is
> smart enough.  Code is for the user to read, and C is not a portable
> assembler language.

OK, I'll make two blocks for FP and integer respectively.  I struggled
a bit updating this hunk with comments for integer comparison
consideration, someone could argue that both can share the same handling
if updating the condition.

> This whole series needs to be factored better, it does way too many
> things, and only marginally related things, at every step.  Or I don't
> see it anyway :-)

OK, I was thinking patch 1/2 is to unify the current vector float
comparison handlings, patch 2/2 is to refine the remaining handlings
for vector integer comparison.  I'm pleased to factor it better, any
suggestions on concrete code is highly appreciated.  :)

btw, I constructed one test case as below, there is no assembly change
before and after this patch.

#define GT(a, b) (((a) > (b)))
#define GE(a, b) (((a) >= (b)))
#define LT(a, b) (((a) < (b)))
#define LE(a, b) (((a) <= (b)))
#define EQ(a, b) (((a) == (b)))
#define NE(a, b) (((a) != (b)))

#define TEST_VECT(NAME, TYPE)                                                  \
  __attribute__ ((noipa)) void test_##NAME##_##TYPE (TYPE *x, TYPE *y,         \
                                                     int *res, int n)          \
  {                                                                            \
    for (int i = 0; i < n; i++)                                                \
      res[i] = NAME (x[i], y[i]);                                              \

#include "stdint.h"

#define TEST(TYPE)                                                             \
  TEST_VECT (GT, TYPE)                                                         \
  TEST_VECT (GE, TYPE)                                                         \
  TEST_VECT (LT, TYPE)                                                         \
  TEST_VECT (LE, TYPE)                                                         \
  TEST_VECT (EQ, TYPE)                                                         \

TEST (int64_t)
TEST (uint64_t)
TEST (int32_t)
TEST (uint32_t)
TEST (int16_t)
TEST (uint16_t)
TEST (int8_t)
TEST (uint8_t)


  reply	other threads:[~2022-11-17  7:52 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-16  6:48 [PATCH 1/2] rs6000: Emit vector fp comparison directly " Kewen.Lin
2022-11-16  6:51 ` [PATCH 2/2] rs6000: Refine integer comparison handlings " Kewen.Lin
2022-11-16 18:58   ` Segher Boessenkool
2022-11-17  7:52     ` Kewen.Lin [this message]
2022-11-18 15:18       ` Segher Boessenkool
2022-11-16 18:44 ` [PATCH 1/2] rs6000: Emit vector fp comparison directly " Segher Boessenkool
2022-11-17  6:59   ` Kewen.Lin
2022-11-18 15:10     ` Segher Boessenkool
2022-11-21  2:01       ` Kewen.Lin
2022-11-27 18:16         ` Segher Boessenkool

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