Re: [PATCH, AArch64 v2 09/11] aarch64: Force TImode values into even registers

[James Greenhalgh]

On Tue, Oct 02, 2018 at 11:19:13AM -0500, Richard Henderson wrote:
> The LSE CASP instruction requires values to be placed in even
> register pairs.  A solution involving two additional register
> classes was rejected in favor of the much simpler solution of
> simply requiring all TImode values to be aligned.

OK.

Thanks,
James

> 
>   * config/aarch64/aarch64.c (aarch64_hard_regno_mode_ok): Force
>   16-byte modes held in GP registers to use an even regno.
> ---
>  gcc/config/aarch64/aarch64.c | 12 
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
> index 49b47382b5d..ce4d7e51d00 100644
> --- a/gcc/config/aarch64/aarch64.c
> +++ b/gcc/config/aarch64/aarch64.c
> @@ -1451,10 +1451,14 @@ aarch64_hard_regno_mode_ok (unsigned regno, 
> machine_mode mode)
>if (regno == FRAME_POINTER_REGNUM || regno == ARG_POINTER_REGNUM)
>  return mode == Pmode;
>  
> -  if (GP_REGNUM_P (regno) && known_le (GET_MODE_SIZE (mode), 16))
> -return true;
> -
> -  if (FP_REGNUM_P (regno))
> +  if (GP_REGNUM_P (regno))
> +{
> +  if (known_le (GET_MODE_SIZE (mode), 8))
> + return true;
> +  else if (known_le (GET_MODE_SIZE (mode), 16))
> + return (regno & 1) == 0;
> +}
> +  else if (FP_REGNUM_P (regno))
>  {
>if (vec_flags & VEC_STRUCT)
>   return end_hard_regno (mode, regno) - 1 <= V31_REGNUM;
> -- 
> 2.17.1
> 

[PATCH, AArch64 v2 09/11] aarch64: Force TImode values into even registers

[Richard Henderson]

The LSE CASP instruction requires values to be placed in even
register pairs.  A solution involving two additional register
classes was rejected in favor of the much simpler solution of
simply requiring all TImode values to be aligned.

* config/aarch64/aarch64.c (aarch64_hard_regno_mode_ok): Force
16-byte modes held in GP registers to use an even regno.
---
 gcc/config/aarch64/aarch64.c | 12 
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 49b47382b5d..ce4d7e51d00 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -1451,10 +1451,14 @@ aarch64_hard_regno_mode_ok (unsigned regno, 
machine_mode mode)
   if (regno == FRAME_POINTER_REGNUM || regno == ARG_POINTER_REGNUM)
 return mode == Pmode;
 
-  if (GP_REGNUM_P (regno) && known_le (GET_MODE_SIZE (mode), 16))
-return true;
-
-  if (FP_REGNUM_P (regno))
+  if (GP_REGNUM_P (regno))
+{
+  if (known_le (GET_MODE_SIZE (mode), 8))
+   return true;
+  else if (known_le (GET_MODE_SIZE (mode), 16))
+   return (regno & 1) == 0;
+}
+  else if (FP_REGNUM_P (regno))
 {
   if (vec_flags & VEC_STRUCT)
return end_hard_regno (mode, regno) - 1 <= V31_REGNUM;
-- 
2.17.1