[PATCH] LoongArch: Slightly simplify loongarch_block_move_straight

[PATCH] LoongArch: Slightly simplify loongarch_block_move_straight

[Xi Ruoyao]

gcc/ChangeLog:

	* config/loongarch/loongarch.cc (loongarch_block_move_straight):
	Check precondition (delta must be a power of 2) and use
	popcount_hwi instead of a homebrew loop.
---

I've not run a full bootstrap with this, but it should be obvious.
Ok for trunk?

 gcc/config/loongarch/loongarch.cc | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index 509ef2b97f1..845fad5a8e8 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -5225,9 +5225,8 @@ loongarch_block_move_straight (rtx dest, rtx src, HOST_WIDE_INT length,
      emit two ld.d/st.d pairs, one ld.w/st.w pair, and one ld.b/st.b
      pair.  For each load/store pair we use a dedicated register to keep
      the pipeline as populated as possible.  */
-  HOST_WIDE_INT num_reg = length / delta;
-  for (delta_cur = delta / 2; delta_cur != 0; delta_cur /= 2)
-    num_reg += !!(length & delta_cur);
+  gcc_assert (pow2p_hwi (delta));
+  HOST_WIDE_INT num_reg = length / delta + popcount_hwi (length % delta);
 
   /* Allocate a buffer for the temporary registers.  */
   regs = XALLOCAVEC (rtx, num_reg);
-- 
2.42.0

Re: [PATCH] LoongArch: Slightly simplify loongarch_block_move_straight

[chenglulu]

在 2023/9/8 上午12:33, Xi Ruoyao 写道:
> gcc/ChangeLog:
>
> 	* config/loongarch/loongarch.cc (loongarch_block_move_straight):
> 	Check precondition (delta must be a power of 2) and use
> 	popcount_hwi instead of a homebrew loop.
> ---
>
> I've not run a full bootstrap with this, but it should be obvious.
> Ok for trunk?

LGTM!

Thanks!

>
>   gcc/config/loongarch/loongarch.cc | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
> index 509ef2b97f1..845fad5a8e8 100644
> --- a/gcc/config/loongarch/loongarch.cc
> +++ b/gcc/config/loongarch/loongarch.cc
> @@ -5225,9 +5225,8 @@ loongarch_block_move_straight (rtx dest, rtx src, HOST_WIDE_INT length,
>        emit two ld.d/st.d pairs, one ld.w/st.w pair, and one ld.b/st.b
>        pair.  For each load/store pair we use a dedicated register to keep
>        the pipeline as populated as possible.  */
> -  HOST_WIDE_INT num_reg = length / delta;
> -  for (delta_cur = delta / 2; delta_cur != 0; delta_cur /= 2)
> -    num_reg += !!(length & delta_cur);
> +  gcc_assert (pow2p_hwi (delta));
> +  HOST_WIDE_INT num_reg = length / delta + popcount_hwi (length % delta);
>   
>     /* Allocate a buffer for the temporary registers.  */
>     regs = XALLOCAVEC (rtx, num_reg);

Pushed: [PATCH] LoongArch: Slightly simplify loongarch_block_move_straight

[Xi Ruoyao]

Pushed r14-3819.

On Sat, 2023-09-09 at 14:16 +0800, chenglulu wrote:
> 
> 在 2023/9/8 上午12:33, Xi Ruoyao 写道:
> > gcc/ChangeLog:
> > 
> >         * config/loongarch/loongarch.cc
> > (loongarch_block_move_straight):
> >         Check precondition (delta must be a power of 2) and use
> >         popcount_hwi instead of a homebrew loop.
> > ---
> > 
> > I've not run a full bootstrap with this, but it should be obvious.
> > Ok for trunk?
> 
> LGTM!
> 
> Thanks!
> 
> > 
> >   gcc/config/loongarch/loongarch.cc | 5 ++---
> >   1 file changed, 2 insertions(+), 3 deletions(-)
> > 
> > diff --git a/gcc/config/loongarch/loongarch.cc
> > b/gcc/config/loongarch/loongarch.cc
> > index 509ef2b97f1..845fad5a8e8 100644
> > --- a/gcc/config/loongarch/loongarch.cc
> > +++ b/gcc/config/loongarch/loongarch.cc
> > @@ -5225,9 +5225,8 @@ loongarch_block_move_straight (rtx dest, rtx
> > src, HOST_WIDE_INT length,
> >        emit two ld.d/st.d pairs, one ld.w/st.w pair, and one
> > ld.b/st.b
> >        pair.  For each load/store pair we use a dedicated register
> > to keep
> >        the pipeline as populated as possible.  */
> > -  HOST_WIDE_INT num_reg = length / delta;
> > -  for (delta_cur = delta / 2; delta_cur != 0; delta_cur /= 2)
> > -    num_reg += !!(length & delta_cur);
> > +  gcc_assert (pow2p_hwi (delta));
> > +  HOST_WIDE_INT num_reg = length / delta + popcount_hwi (length %
> > delta);
> >   
> >     /* Allocate a buffer for the temporary registers.  */
> >     regs = XALLOCAVEC (rtx, num_reg);
> 

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University