* [PATCH] RISC-V: avoid splitting small constant in <or_optab>i<mode>_extrabit pattern
@ 2023-04-10 5:07 Lin Sinan
2023-04-10 15:57 ` Jeff Law
2023-04-11 16:28 ` Jeff Law
0 siblings, 2 replies; 5+ messages in thread
From: Lin Sinan @ 2023-04-10 5:07 UTC (permalink / raw)
To: gcc-patches; +Cc: philipp.tomsich, kito.cheng, palmer, andrew, Sinan Lin
From: Sinan Lin <linsinan.lsn@linux.alibaba.com>
there is no need to split an xori/ori with an small constant. take the test
case `int foo(int idx) { return idx|3; }` as an example,
rv64im_zba generates:
ori a0,a0,3
ret
but, rv64im_zba_zbs generates:
ori a0,a0,1
ori a0,a0,2
ret
with this change, insn `ori r2,r1,3` will not be splitted in zbs.
---
gcc/config/riscv/predicates.md | 2 +-
| 14 ++++++++++++++
2 files changed, 15 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c
diff --git a/gcc/config/riscv/predicates.md b/gcc/config/riscv/predicates.md
index 0d9d7701c7e..8654dbc5943 100644
--- a/gcc/config/riscv/predicates.md
+++ b/gcc/config/riscv/predicates.md
@@ -399,7 +399,7 @@
(define_predicate "uimm_extra_bit_or_twobits"
(and (match_code "const_int")
(ior (match_operand 0 "uimm_extra_bit_operand")
- (match_operand 0 "const_twobits_operand"))))
+ (match_operand 0 "const_twobits_not_arith_operand"))))
;; A CONST_INT operand that fits into the negative half of a
;; signed-immediate after a single cleared top bit has been
--git a/gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c b/gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c
new file mode 100644
index 00000000000..ef7ed60461a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gc_zbs -mabi=lp64" } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-Og" } } */
+
+int or_two_bit(int idx) {
+ return idx|3;
+}
+
+int xor_two_bit(int idx) {
+ return idx^3;
+}
+
+/* { dg-final { scan-assembler-times "\tori\t" 1 } } */
+/* { dg-final { scan-assembler-times "\txori\t" 1 } } */
--
2.19.1.6.gb485710b
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] RISC-V: avoid splitting small constant in <or_optab>i<mode>_extrabit pattern
2023-04-10 5:07 [PATCH] RISC-V: avoid splitting small constant in <or_optab>i<mode>_extrabit pattern Lin Sinan
@ 2023-04-10 15:57 ` Jeff Law
2023-04-10 20:59 ` Philipp Tomsich
2023-04-11 16:28 ` Jeff Law
1 sibling, 1 reply; 5+ messages in thread
From: Jeff Law @ 2023-04-10 15:57 UTC (permalink / raw)
To: Lin Sinan, gcc-patches
Cc: philipp.tomsich, kito.cheng, palmer, andrew, Sinan Lin
On 4/9/23 23:07, Lin Sinan via Gcc-patches wrote:
> From: Sinan Lin <linsinan.lsn@linux.alibaba.com>
>
> there is no need to split an xori/ori with an small constant. take the test
> case `int foo(int idx) { return idx|3; }` as an example,
>
> rv64im_zba generates:
> ori a0,a0,3
> ret
> but, rv64im_zba_zbs generates:
> ori a0,a0,1
> ori a0,a0,2
> ret
>
> with this change, insn `ori r2,r1,3` will not be splitted in zbs.
> ---
> gcc/config/riscv/predicates.md | 2 +-
> .../gcc.target/riscv/zbs-extra-bit-or-twobits.c | 14 ++++++++++++++
> 2 files changed, 15 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c
A minor oversight in the VRULL patches in this space. This is actually
a regression as we were previously generating the single [xo]ri.
The patch looks fine, though it does need to go through a test cycle.
jeff
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] RISC-V: avoid splitting small constant in <or_optab>i<mode>_extrabit pattern
2023-04-10 15:57 ` Jeff Law
@ 2023-04-10 20:59 ` Philipp Tomsich
2023-04-11 16:19 ` Jeff Law
0 siblings, 1 reply; 5+ messages in thread
From: Philipp Tomsich @ 2023-04-10 20:59 UTC (permalink / raw)
To: Jeff Law; +Cc: Lin Sinan, gcc-patches, kito.cheng, palmer, andrew, Sinan Lin
On Mon, 10 Apr 2023 at 17:57, Jeff Law <jeffreyalaw@gmail.com> wrote:
>
>
>
> On 4/9/23 23:07, Lin Sinan via Gcc-patches wrote:
> > From: Sinan Lin <linsinan.lsn@linux.alibaba.com>
> >
> > there is no need to split an xori/ori with an small constant. take the test
> > case `int foo(int idx) { return idx|3; }` as an example,
> >
> > rv64im_zba generates:
> > ori a0,a0,3
> > ret
> > but, rv64im_zba_zbs generates:
> > ori a0,a0,1
> > ori a0,a0,2
> > ret
> >
> > with this change, insn `ori r2,r1,3` will not be splitted in zbs.
> > ---
> > gcc/config/riscv/predicates.md | 2 +-
> > .../gcc.target/riscv/zbs-extra-bit-or-twobits.c | 14 ++++++++++++++
> > 2 files changed, 15 insertions(+), 1 deletion(-)
> > create mode 100644 gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c
> A minor oversight in the VRULL patches in this space. This is actually
> a regression as we were previously generating the single [xo]ri.
Thanks for catching this one!
I looked this change over and it looks fine. I hope this is the last
fallout from this set of changes.
>
> The patch looks fine, though it does need to go through a test cycle.
>
> jeff
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] RISC-V: avoid splitting small constant in <or_optab>i<mode>_extrabit pattern
2023-04-10 20:59 ` Philipp Tomsich
@ 2023-04-11 16:19 ` Jeff Law
0 siblings, 0 replies; 5+ messages in thread
From: Jeff Law @ 2023-04-11 16:19 UTC (permalink / raw)
To: Philipp Tomsich
Cc: Lin Sinan, gcc-patches, kito.cheng, palmer, andrew, Sinan Lin
On 4/10/23 14:59, Philipp Tomsich wrote:
> On Mon, 10 Apr 2023 at 17:57, Jeff Law <jeffreyalaw@gmail.com> wrote:
>>
>>
>>
>> On 4/9/23 23:07, Lin Sinan via Gcc-patches wrote:
>>> From: Sinan Lin <linsinan.lsn@linux.alibaba.com>
>>>
>>> there is no need to split an xori/ori with an small constant. take the test
>>> case `int foo(int idx) { return idx|3; }` as an example,
>>>
>>> rv64im_zba generates:
>>> ori a0,a0,3
>>> ret
>>> but, rv64im_zba_zbs generates:
>>> ori a0,a0,1
>>> ori a0,a0,2
>>> ret
>>>
>>> with this change, insn `ori r2,r1,3` will not be splitted in zbs.
>>> ---
>>> gcc/config/riscv/predicates.md | 2 +-
>>> .../gcc.target/riscv/zbs-extra-bit-or-twobits.c | 14 ++++++++++++++
>>> 2 files changed, 15 insertions(+), 1 deletion(-)
>>> create mode 100644 gcc/testsuite/gcc.target/riscv/zbs-extra-bit-or-twobits.c
>> A minor oversight in the VRULL patches in this space. This is actually
>> a regression as we were previously generating the single [xo]ri.
>
> Thanks for catching this one!
>
> I looked this change over and it looks fine. I hope this is the last
> fallout from this set of changes.
Just for completeness, I bootstrapped and regression tested Sinan's
change on rv64. Given it's a regression, I'm going to go ahead and
commit it to the trunk momentarily.
jeff
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] RISC-V: avoid splitting small constant in <or_optab>i<mode>_extrabit pattern
2023-04-10 5:07 [PATCH] RISC-V: avoid splitting small constant in <or_optab>i<mode>_extrabit pattern Lin Sinan
2023-04-10 15:57 ` Jeff Law
@ 2023-04-11 16:28 ` Jeff Law
1 sibling, 0 replies; 5+ messages in thread
From: Jeff Law @ 2023-04-11 16:28 UTC (permalink / raw)
To: Lin Sinan, gcc-patches
Cc: philipp.tomsich, kito.cheng, palmer, andrew, Sinan Lin
On 4/9/23 23:07, Lin Sinan via Gcc-patches wrote:
> From: Sinan Lin <linsinan.lsn@linux.alibaba.com>
>
> there is no need to split an xori/ori with an small constant. take the test
> case `int foo(int idx) { return idx|3; }` as an example,
>
> rv64im_zba generates:
> ori a0,a0,3
> ret
> but, rv64im_zba_zbs generates:
> ori a0,a0,1
> ori a0,a0,2
> ret
>
> with this change, insn `ori r2,r1,3` will not be splitted in zbs.
As noted, this was actually a regression. I've bootstrapped this change
on rv64 with no regressions and pushed it to the trunk.
Thanks!
jeff
^ permalink raw reply [flat|nested] 5+ messages in thread
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2023-04-10 5:07 [PATCH] RISC-V: avoid splitting small constant in <or_optab>i<mode>_extrabit pattern Lin Sinan
2023-04-10 15:57 ` Jeff Law
2023-04-10 20:59 ` Philipp Tomsich
2023-04-11 16:19 ` Jeff Law
2023-04-11 16:28 ` Jeff Law
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