* Re: [PATCH] arm: Support gcc older than 10 for find_zero_all
@ 2023-02-22 16:37 Wilco Dijkstra
0 siblings, 0 replies; 3+ messages in thread
From: Wilco Dijkstra @ 2023-02-22 16:37 UTC (permalink / raw)
To: Adhemerval Zanella; +Cc: 'GNU C Library'
Hi Adhemerval,
> __builtin_arm_uqsub8 is only available on gcc newer or equal than 10.
> +#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
__builtin_arm_uqsub8 is an internal builtin function which might change -
the correct way is to include "arm_acle.h" and use __uqsub8 (). Since LLVM
doesn't seem to support this, it may be easier to only keep the inline assembler
for now.
Cheers,
Wilco
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] arm: Support gcc older than 10 for find_zero_all
2023-02-20 16:48 Adhemerval Zanella
@ 2023-02-20 19:26 ` Richard Henderson
0 siblings, 0 replies; 3+ messages in thread
From: Richard Henderson @ 2023-02-20 19:26 UTC (permalink / raw)
To: Adhemerval Zanella, libc-alpha, Szabolcs Nagy
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. */
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] arm: Support gcc older than 10 for find_zero_all
@ 2023-02-20 16:48 Adhemerval Zanella
2023-02-20 19:26 ` Richard Henderson
0 siblings, 1 reply; 3+ messages in thread
From: Adhemerval Zanella @ 2023-02-20 16:48 UTC (permalink / raw)
To: libc-alpha, Szabolcs Nagy
__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(+)
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. */
--
2.34.1
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-02-22 16:37 [PATCH] arm: Support gcc older than 10 for find_zero_all Wilco Dijkstra
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2023-02-20 16:48 Adhemerval Zanella
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