on 2022/1/13 下午11:15, David Edelsohn wrote:
> On Thu, Jan 13, 2022 at 7:40 AM Kewen.Lin <li...@linux.ibm.com> wrote:
>>
>> Hi David,
>>
>> on 2022/1/13 上午11:12, David Edelsohn wrote:
>>> On Wed, Jan 12, 2022 at 8:56 PM Kewen.Lin <li...@linux.ibm.com> wrote:
>>>>
>>>> Hi,
>>>>
>>>> This patch is to clean up some codes with GET_MODE_UNIT_SIZE or
>>>> GET_MODE_NUNITS, which can use known constant instead.
>>>
>>> I'll let Segher decide, but often the additional code is useful
>>> self-documentation instead of magic constants. Or at least the change
>>> requires comments documenting the derivation of the constants
>>> currently described by the code itself.
>>>
>>
>> Thanks for the comments, I added some comments as suggested, also removed
>> the whole "altivec_vreveti2" since I noticed it's useless, it's not used
>> by any built-in functions and even unused in the commit db042e1603db50573.
>>
>> The updated version has been tested as before.
>
> As we have discussed offline, the comments need to be clarified and expanded.
>
> And the removal of altivec_vreveti2 should be confirmed with Carl
> Love, who added the pattern less than a year ago. There may be another
> patch planning to use it.
>
Thanks for the suggestions David! The comments have been updated, and Carl
also helped to confirm the altivec_vreveti2 pattern is not planned for any
future work and looks reasonable to remove.
Does this updated version look good to you?
BR,
Kewen
-----
gcc/ChangeLog:
* config/rs6000/altivec.md (altivec_vreveti2): Remove.
* config/rs6000/vsx.md (*vsx_extract_si, *vsx_extract_si_<uns>float_df,
*vsx_extract_si_<uns>float_<mode>, *vsx_insert_extract_v4sf_p9): Use
known constant values to simplify code.
---
gcc/config/rs6000/altivec.md | 25 -------------------------
gcc/config/rs6000/vsx.md | 16 ++++++++++++----
2 files changed, 12 insertions(+), 29 deletions(-)
diff --git a/gcc/config/rs6000/altivec.md b/gcc/config/rs6000/altivec.md
index 950b17862c4..4412175a0dc 100644
--- a/gcc/config/rs6000/altivec.md
+++ b/gcc/config/rs6000/altivec.md
@@ -3950,31 +3950,6 @@
DONE;
})
-;; Vector reverse elements
-(define_expand "altivec_vreveti2"
- [(set (match_operand:TI 0 "register_operand" "=v")
- (unspec:TI [(match_operand:TI 1 "register_operand" "v")]
- UNSPEC_VREVEV))]
- "TARGET_ALTIVEC"
-{
- int i, j, size, num_elements;
- rtvec v = rtvec_alloc (16);
- rtx mask = gen_reg_rtx (V16QImode);
-
- size = GET_MODE_UNIT_SIZE (TImode);
- num_elements = GET_MODE_NUNITS (TImode);
-
- for (j = 0; j < num_elements; j++)
- for (i = 0; i < size; i++)
- RTVEC_ELT (v, i + j * size)
- = GEN_INT (i + (num_elements - 1 - j) * size);
-
- emit_insn (gen_vec_initv16qiqi (mask, gen_rtx_PARALLEL (V16QImode, v)));
- emit_insn (gen_altivec_vperm_ti (operands[0], operands[1],
- operands[1], mask));
- DONE;
-})
-
;; Vector reverse elements for V16QI V8HI V4SI V4SF
(define_expand "altivec_vreve<mode>2"
[(set (match_operand:VEC_K 0 "register_operand" "=v")
diff --git a/gcc/config/rs6000/vsx.md b/gcc/config/rs6000/vsx.md
index acd729d1687..ee748ff4ebd 100644
--- a/gcc/config/rs6000/vsx.md
+++ b/gcc/config/rs6000/vsx.md
@@ -3854,8 +3854,10 @@
rtx vec_tmp = operands[3];
int value;
+ /* Adjust index for LE element ordering, the below minuend 3 is computed by
+ GET_MODE_NUNITS (V4SImode) - 1. */
if (!BYTES_BIG_ENDIAN)
- element = GEN_INT (GET_MODE_NUNITS (V4SImode) - 1 - INTVAL (element));
+ element = GEN_INT (3 - INTVAL (element));
/* If the value is in the correct position, we can avoid doing the VSPLT<x>
instruction. */
@@ -4230,8 +4232,10 @@
rtx v4si_tmp = operands[3];
int value;
+ /* Adjust index for LE element ordering, the below minuend 3 is computed by
+ GET_MODE_NUNITS (V4SImode) - 1. */
if (!BYTES_BIG_ENDIAN)
- element = GEN_INT (GET_MODE_NUNITS (V4SImode) - 1 - INTVAL (element));
+ element = GEN_INT (3 - INTVAL (element));
/* If the value is in the correct position, we can avoid doing the VSPLT<x>
instruction. */
@@ -4273,8 +4277,10 @@
rtx df_tmp = operands[4];
int value;
+ /* Adjust index for LE element ordering, the below minuend 3 is computed by
+ GET_MODE_NUNITS (V4SImode) - 1. */
if (!BYTES_BIG_ENDIAN)
- element = GEN_INT (GET_MODE_NUNITS (V4SImode) - 1 - INTVAL (element));
+ element = GEN_INT (3 - INTVAL (element));
/* If the value is in the correct position, we can avoid doing the VSPLT<x>
instruction. */
@@ -4466,8 +4472,10 @@
{
int ele = INTVAL (operands[4]);
+ /* Adjust index for LE element ordering, the below minuend 3 is computed by
+ GET_MODE_NUNITS (V4SFmode) - 1. */
if (!BYTES_BIG_ENDIAN)
- ele = GET_MODE_NUNITS (V4SFmode) - 1 - ele;
+ ele = 3 - ele;
operands[4] = GEN_INT (GET_MODE_SIZE (SFmode) * ele);
return "xxinsertw %x0,%x2,%4";
