[PATCH 1/2] opcodes: LoongArch: make all non-native jumps desugar to canonical b{lt/ge}[u] forms
liuzhensong
liuzhensong@loongson.cn
Fri Jul 29 10:02:00 GMT 2022
在 2022/7/29 下午5:42, WANG Xuerui 写道:
> On 2022/7/29 09:18, liuzhensong wrote:
>>
>>
>> On 2022/7/27 下午7:07, WANG Xuerui wrote:
>>> From: WANG Xuerui<git@xen0n.name>
>>>
>>> Also re-order the jump/branch opcodes while at it, so that insns are
>>> sorted in ascending order according to opcodes, and the label form
>>> preceding the real definition.
>>> ---
>>> opcodes/loongarch-opc.c | 31 ++++++++++++-------------------
>>> 1 file changed, 12 insertions(+), 19 deletions(-)
>>>
>>> diff --git a/opcodes/loongarch-opc.c b/opcodes/loongarch-opc.c
>>> index 08ba101a902..6f5e42d57e5 100644
>>> --- a/opcodes/loongarch-opc.c
>>> +++ b/opcodes/loongarch-opc.c
>>> @@ -810,22 +810,13 @@ static struct loongarch_opcode
>>> loongarch_float_jmp_opcodes[] =
>>> static struct loongarch_opcode loongarch_jmp_opcodes[] =
>>> {
>>> /* match, mask, name, format,
>>> macro, include, exclude, pinfo. */
>>> - { 0x0, 0x0, "bltz", "r,la", "bltz
>>> %1,%%b16(%2)", 0, 0, 0 },
>>> - { 0x60000000, 0xfc00001f, "bltz", "r5:5,sb10:16<<2",
>>> 0, 0, 0, 0 },
>>> - { 0x0, 0x0, "bgtz", "r,la", "bgtz
>>> %1,%%b16(%2)", 0, 0, 0 },
>>> - { 0x60000000, 0xfc0003e0, "bgtz", "r0:5,sb10:16<<2",
>>> 0, 0, 0, 0 },
>>> - { 0x0, 0x0, "bgez", "r,la", "bgez
>>> %1,%%b16(%2)", 0, 0, 0 },
>>> - { 0x64000000, 0xfc00001f, "bgez", "r5:5,sb10:16<<2",
>>> 0, 0, 0, 0 },
>>> - { 0x0, 0x0, "blez", "r,la", "blez
>>> %1,%%b16(%2)", 0, 0, 0 },
>>> - { 0x64000000, 0xfc0003e0, "blez", "r0:5,sb10:16<<2",
>>> 0, 0, 0, 0 },
>>> { 0x0, 0x0, "beqz", "r,la", "beqz
>>> %1,%%b21(%2)", 0, 0, 0 },
>>> { 0x40000000, 0xfc000000, "beqz",
>>> "r5:5,sb0:5|10:16<<2", 0, 0, 0, 0 },
>>> { 0x0, 0x0, "bnez", "r,la", "bnez
>>> %1,%%b21(%2)", 0, 0, 0 },
>>> { 0x44000000, 0xfc000000, "bnez",
>>> "r5:5,sb0:5|10:16<<2", 0, 0, 0, 0 },
>>> - { 0x0, 0x0, "jr", "r", "jirl $r0,%1,0",
>>> 0, 0, 0 },
>>> - { 0x50000000, 0xfc000000, "b", "sb0:10|10:16<<2",
>>> 0, 0, 0, 0 },
>>> - { 0x0, 0x0, "b", "la", "b
>>> %%b26(%1)", 0, 0, 0 },
>>> { 0x4c000000, 0xfc000000, "jirl",
>>> "r0:5,r5:5,s10:16<<2", 0, 0, 0, 0 },
>>> + { 0x0, 0x0, "b", "la", "b
>>> %%b26(%1)", 0, 0, 0 },
>>> + { 0x50000000, 0xfc000000, "b", "sb0:10|10:16<<2",
>>> 0, 0, 0, 0 },
>>> { 0x0, 0x0, "bl", "la", "bl
>>> %%b26(%1)", 0, 0, 0 },
>>> { 0x54000000, 0xfc000000, "bl", "sb0:10|10:16<<2",
>>> 0, 0, 0, 0 },
>>> { 0x0, 0x0, "beq", "r,r,la", "beq
>>> %1,%2,%%b16(%3)", 0, 0, 0 },
>>> @@ -834,20 +825,22 @@ static struct loongarch_opcode
>>> loongarch_jmp_opcodes[] =
>>> { 0x5c000000, 0xfc000000, "bne",
>>> "r5:5,r0:5,sb10:16<<2", 0, 0, 0, 0 },
>>> { 0x0, 0x0, "blt", "r,r,la", "blt
>>> %1,%2,%%b16(%3)", 0, 0, 0 },
>>> { 0x60000000, 0xfc000000, "blt",
>>> "r5:5,r0:5,sb10:16<<2", 0, 0, 0, 0 },
>>> - { 0x0, 0x0, "bgt", "r,r,la", "bgt
>>> %1,%2,%%b16(%3)", 0, 0, 0 },
>>> - { 0x60000000, 0xfc000000, "bgt",
>>> "r0:5,r5:5,sb10:16<<2", 0, 0, 0, 0 },
>>> { 0x0, 0x0, "bge", "r,r,la", "bge
>>> %1,%2,%%b16(%3)", 0, 0, 0 },
>>> { 0x64000000, 0xfc000000, "bge",
>>> "r5:5,r0:5,sb10:16<<2", 0, 0, 0, 0 },
>>> - { 0x0, 0x0, "ble", "r,r,la", "ble
>>> %1,%2,%%b16(%3)", 0, 0, 0 },
>>> - { 0x64000000, 0xfc000000, "ble",
>>> "r0:5,r5:5,sb10:16<<2", 0, 0, 0, 0 },
>>> { 0x0, 0x0, "bltu", "r,r,la", "bltu
>>> %1,%2,%%b16(%3)", 0, 0, 0 },
>>> { 0x68000000, 0xfc000000, "bltu",
>>> "r5:5,r0:5,sb10:16<<2", 0, 0, 0, 0 },
>>> - { 0x0, 0x0, "bgtu", "r,r,la", "bgtu
>>> %1,%2,%%b16(%3)", 0, 0, 0 },
>>> - { 0x68000000, 0xfc000000, "bgtu",
>>> "r0:5,r5:5,sb10:16<<2", 0, 0, 0, 0 },
>>> { 0x0, 0x0, "bgeu", "r,r,la", "bgeu
>>> %1,%2,%%b16(%3)", 0, 0, 0 },
>>> { 0x6c000000, 0xfc000000, "bgeu",
>>> "r5:5,r0:5,sb10:16<<2", 0, 0, 0, 0 },
>>> - { 0x0, 0x0, "bleu", "r,r,la", "bleu
>>> %1,%2,%%b16(%3)", 0, 0, 0 },
>>> - { 0x6c000000, 0xfc000000, "bleu",
>>> "r0:5,r5:5,sb10:16<<2", 0, 0, 0, 0 },
>>> + /* Jumps implemented with macros. */
>>> + { 0x0, 0x0, "bgt", "r,r,la", "blt
>>> %2,%1,%%b16(%3)", 0, 0, 0 },
>>> + { 0x0, 0x0, "ble", "r,r,la", "bge
>>> %2,%1,%%b16(%3)", 0, 0, 0 },
>>> + { 0x0, 0x0, "bltz", "r,la", "blt
>>> %1,$r0,%%b16(%2)", 0, 0, 0 },
>>> + { 0x0, 0x0, "bgtz", "r,la", "blt
>>> $r0,%1,%%b16(%2)", 0, 0, 0 },
>>> + { 0x0, 0x0, "bgez", "r,la", "bge
>>> %1,$r0,%%b16(%2)", 0, 0, 0 },
>>> + { 0x0, 0x0, "blez", "r,la", "bge
>>> $r0,%1,%%b16(%2)", 0, 0, 0 },
>>> + { 0x0, 0x0, "bgtu", "r,r,la", "bltu
>>> %2,%1,%%b16(%3)", 0, 0, 0 },
>>> + { 0x0, 0x0, "bleu", "r,r,la", "bgeu
>>> %2,%1,%%b16(%3)", 0, 0, 0 },
>>> + { 0x0, 0x0, "jr", "r", "jirl $r0,%1,0",
>>> 0, 0, 0 },
>>> { 0 } /* Terminate the list. */
>>> };
>> Looks good to me. And I don't think the instruction "ret" is
>> necessary in [PATCH 2/2].
>
> Please don't be so subjective. You and Chenghua never gave objective
> reasons against "ret", your rejections seem to be just based on some
> kind of personal preference. All while ignoring the objective
> readability improvement and ease of learning gained by adding such
> support, and I believe there must be community members in favor of the
> addition.
>
> And it's not like everyone must immediately migrate to it, people may
> well continue to write "jr ra" or even "jirl zero, ra, 0", only those
> of us preferring brevity would have one more palatable choice...
If gcc is not required to be generated instruction "ret" by default, I
think it can be added.
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