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 vector.md, 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. */
>> + if (GET_MODE_CLASS (dmode) == MODE_VECTOR_FLOAT
>> + || 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_VECT (NE, 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)
BR,
Kewen
