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RISC-V: In pipeline scheduling, insns should not be fusion in different BB blocks.

Message ID 20230525083231.234-1-jinma@linux.alibaba.com
State Accepted
Headers
Series RISC-V: In pipeline scheduling, insns should not be fusion in different BB blocks. |

Checks

Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

Jin Ma May 25, 2023, 8:32 a.m. UTC 
  When the last insn1 of BB1 and the first insn2 of BB2 are fusion, insn2 will
clear all dependencies in the function chain_to_prev_insn, resulting in insn2
may mov to any BB, and the program calculation result is wrong.

gcc/ChangeLog:

	* sched-deps.cc (sched_macro_fuse_insns): Insns should not be fusion
	in different BB blocks
---
 gcc/sched-deps.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Richard Sandiford May 25, 2023, 9:22 a.m. UTC | #1 
Jin Ma <jinma@linux.alibaba.com> writes:
> When the last insn1 of BB1 and the first insn2 of BB2 are fusion, insn2 will
> clear all dependencies in the function chain_to_prev_insn, resulting in insn2
> may mov to any BB, and the program calculation result is wrong.
>
> gcc/ChangeLog:
>
> 	* sched-deps.cc (sched_macro_fuse_insns): Insns should not be fusion
> 	in different BB blocks
> ---
>  gcc/sched-deps.cc | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/gcc/sched-deps.cc b/gcc/sched-deps.cc
> index 2aa6623ad2e..998fe930804 100644
> --- a/gcc/sched-deps.cc
> +++ b/gcc/sched-deps.cc
> @@ -2833,7 +2833,7 @@ sched_macro_fuse_insns (rtx_insn *insn)
>       compile time complexity.  */
>    if (DEBUG_INSN_P (insn))
>      return;
> -  prev = prev_nonnote_nondebug_insn (insn);
> +  prev = prev_nonnote_nondebug_insn_bb (insn);
>    if (!prev)
>      return;

Huh, kind-of impressed we managed to go so long without hitting this.

The patch is OK, thanks (and for branches too if necessary).

Richard
Jeff Law May 25, 2023, 1:46 p.m. UTC | #2 
On 5/25/23 03:22, Richard Sandiford wrote:
> Jin Ma <jinma@linux.alibaba.com> writes:
>> When the last insn1 of BB1 and the first insn2 of BB2 are fusion, insn2 will
>> clear all dependencies in the function chain_to_prev_insn, resulting in insn2
>> may mov to any BB, and the program calculation result is wrong.
>>
>> gcc/ChangeLog:
>>
>> 	* sched-deps.cc (sched_macro_fuse_insns): Insns should not be fusion
>> 	in different BB blocks
>> ---
>>   gcc/sched-deps.cc | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/gcc/sched-deps.cc b/gcc/sched-deps.cc
>> index 2aa6623ad2e..998fe930804 100644
>> --- a/gcc/sched-deps.cc
>> +++ b/gcc/sched-deps.cc
>> @@ -2833,7 +2833,7 @@ sched_macro_fuse_insns (rtx_insn *insn)
>>        compile time complexity.  */
>>     if (DEBUG_INSN_P (insn))
>>       return;
>> -  prev = prev_nonnote_nondebug_insn (insn);
>> +  prev = prev_nonnote_nondebug_insn_bb (insn);
>>     if (!prev)
>>       return;
> 
> Huh, kind-of impressed we managed to go so long without hitting this.
Yea.  I suspect a lot of the fusion cases we've handled until now have 
been more focused on things like compare+branch on x86 which are going 
to be in the same block.

> 
> The patch is OK, thanks (and for branches too if necessary).
I don't think Jin has commit privs, so I'll push it to the trunk and 
active release branches.

jeff
Jeff Law May 25, 2023, 5:57 p.m. UTC | #3 
On 5/25/23 02:32, Jin Ma wrote:
> When the last insn1 of BB1 and the first insn2 of BB2 are fusion, insn2 will
> clear all dependencies in the function chain_to_prev_insn, resulting in insn2
> may mov to any BB, and the program calculation result is wrong.
> 
> gcc/ChangeLog:
> 
> 	* sched-deps.cc (sched_macro_fuse_insns): Insns should not be fusion
> 	in different BB blocks
I've pushed this to the trunk.  After a week or so I'll push it to the 
active release branches.

jeff
diff mbox series

Patch

diff --git a/gcc/sched-deps.cc b/gcc/sched-deps.cc
index 2aa6623ad2e..998fe930804 100644
--- a/gcc/sched-deps.cc
+++ b/gcc/sched-deps.cc
@@ -2833,7 +2833,7 @@  sched_macro_fuse_insns (rtx_insn *insn)
      compile time complexity.  */
   if (DEBUG_INSN_P (insn))
     return;
-  prev = prev_nonnote_nondebug_insn (insn);
+  prev = prev_nonnote_nondebug_insn_bb (insn);
   if (!prev)
     return;