arm: Support gcc older than 10 for find_zero_all

Message ID 20230220164809.2581181-1-adhemerval.zanella@linaro.org
State Committed
Commit 97830304bb477f18b67b7bc11989fb3357da443e
Headers
Series arm: Support gcc older than 10 for find_zero_all |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent
dj/TryBot-32bit success Build for i686

Commit Message

Adhemerval Zanella Netto Feb. 20, 2023, 4:48 p.m. UTC
  __builtin_arm_uqsub8 is only available on gcc newer or equal than 10.

Checked on arm-linux-gnueabihf built with gcc 9.
---
 sysdeps/arm/armv6t2/string-fza.h | 6 ++++++
 1 file changed, 6 insertions(+)
  

Comments

Richard Henderson Feb. 20, 2023, 7:26 p.m. UTC | #1
On 2/20/23 06:48, Adhemerval Zanella via Libc-alpha wrote:
> __builtin_arm_uqsub8 is only available on gcc newer or equal than 10.
> 
> Checked on arm-linux-gnueabihf built with gcc 9.
> ---
>   sysdeps/arm/armv6t2/string-fza.h | 6 ++++++
>   1 file changed, 6 insertions(+)

Whoops, thanks.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

> 
> diff --git a/sysdeps/arm/armv6t2/string-fza.h b/sysdeps/arm/armv6t2/string-fza.h
> index 76274ccca7..d85ce86434 100644
> --- a/sysdeps/arm/armv6t2/string-fza.h
> +++ b/sysdeps/arm/armv6t2/string-fza.h
> @@ -33,7 +33,13 @@ find_zero_all (op_t x)
>     /* Use unsigned saturated subtraction from 1 in each byte.
>        That leaves 1 for every byte that was zero.  */
>     op_t ones = repeat_bytes (0x01);
> +#if __GNUC_PREREQ (10, 0)
>     return __builtin_arm_uqsub8 (ones, x);
> +#else
> +  op_t ret;
> +  asm ("uqsub8 %0,%1,%2" : "=r"(ret) : "r"(ones), "r"(x));
> +  return ret;
> +#endif
>   }
>   
>   /* Identify bytes that are equal between X1 and X2.  */
  

Patch

diff --git a/sysdeps/arm/armv6t2/string-fza.h b/sysdeps/arm/armv6t2/string-fza.h
index 76274ccca7..d85ce86434 100644
--- a/sysdeps/arm/armv6t2/string-fza.h
+++ b/sysdeps/arm/armv6t2/string-fza.h
@@ -33,7 +33,13 @@  find_zero_all (op_t x)
   /* Use unsigned saturated subtraction from 1 in each byte.
      That leaves 1 for every byte that was zero.  */
   op_t ones = repeat_bytes (0x01);
+#if __GNUC_PREREQ (10, 0)
   return __builtin_arm_uqsub8 (ones, x);
+#else
+  op_t ret;
+  asm ("uqsub8 %0,%1,%2" : "=r"(ret) : "r"(ones), "r"(x));
+  return ret;
+#endif
 }
 
 /* Identify bytes that are equal between X1 and X2.  */